src/com/android/launcher2/AppsCustomizePagedView.java

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.launcher2;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.animation.PropertyValuesHolder;
import android.app.WallpaperManager;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProviderInfo;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.util.LruCache;
import android.util.Slog;
import android.util.TypedValue;
import android.util.Xml;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.LinearInterpolator;
import android.widget.ImageView;
import android.widget.TextView;

import com.android.launcher.R;

public class AppsCustomizePagedView extends PagedViewWithDraggableItems implements
        AllAppsView, View.OnClickListener, DragSource {
    static final String LOG_TAG = "AppsCustomizePagedView";

    /**
     * The different content types that this paged view can show.
     */
    public enum ContentType {
        Applications,
        Widgets,
        Wallpapers
    }

    // Refs
    private Launcher mLauncher;
    private DragController mDragController;
    private final LayoutInflater mLayoutInflater;
    private final PackageManager mPackageManager;

    // Content
    private ContentType mContentType;
    private ArrayList<ApplicationInfo> mApps;
    private List<Object> mWidgets;
    private List<ResolveInfo> mWallpapers;

    // Caching
    private Drawable mDefaultWidgetBackground;
    private final int sWidgetPreviewCacheSize = 1 * 1024 * 1024; // 1 MiB
    private LruCache<Object, Bitmap> mWidgetPreviewCache;
    private IconCache mIconCache;

    // Dimens
    private int mContentWidth;
    private int mMaxWidgetSpan, mMinWidgetSpan;
    private int mCellWidthGap, mCellHeightGap;
    private int mWidgetCountX, mWidgetCountY;
    private int mWallpaperCountX, mWallpaperCountY;
    private final int mWidgetPreviewIconPaddedDimension;
    private final float sWidgetPreviewIconPaddingPercentage = 0.25f;
    private PagedViewCellLayout mWidgetSpacingLayout;

    // Animations
    private final float ANIMATION_SCALE = 0.5f;
    private final int TRANSLATE_ANIM_DURATION = 400;
    private final int DROP_ANIM_DURATION = 200;

    public AppsCustomizePagedView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mLayoutInflater = LayoutInflater.from(context);
        mPackageManager = context.getPackageManager();
        mContentType = ContentType.Applications;
        mApps = new ArrayList<ApplicationInfo>();
        mWidgets = new ArrayList<Object>();
        mWallpapers = new ArrayList<ResolveInfo>();
        mIconCache = ((LauncherApplication) context.getApplicationContext()).getIconCache();
        mWidgetPreviewCache = new LruCache<Object, Bitmap>(sWidgetPreviewCacheSize) {
            protected int sizeOf(Object key, Bitmap value) {
                return value.getByteCount();
            }
        };

        // Save the default widget preview background
        Resources resources = context.getResources();
        mDefaultWidgetBackground = resources.getDrawable(R.drawable.default_widget_preview);

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PagedView, 0, 0);
        mCellCountX = a.getInt(R.styleable.PagedView_cellCountX, 6);
        mCellCountY = a.getInt(R.styleable.PagedView_cellCountY, 4);
        a.recycle();
        a = context.obtainStyledAttributes(attrs, R.styleable.AppsCustomizePagedView, 0, 0);
        mCellWidthGap =
            a.getDimensionPixelSize(R.styleable.AppsCustomizePagedView_widgetCellWidthGap, 10);
        mCellHeightGap =
            a.getDimensionPixelSize(R.styleable.AppsCustomizePagedView_widgetCellHeightGap, 10);
        mWidgetCountX = a.getInt(R.styleable.AppsCustomizePagedView_widgetCountX, 2);
        mWidgetCountY = a.getInt(R.styleable.AppsCustomizePagedView_widgetCountY, 2);
        mWallpaperCountX = a.getInt(R.styleable.AppsCustomizePagedView_wallpaperCountX, 2);
        mWallpaperCountY = a.getInt(R.styleable.AppsCustomizePagedView_wallpaperCountY, 2);
        a.recycle();

        // Create a dummy page that we can use to approximate the cell dimensions of widgets and
        // the content width (to be used by our parent)
        mWidgetSpacingLayout = new PagedViewCellLayout(context);
        setupPage(mWidgetSpacingLayout);
        mContentWidth = mWidgetSpacingLayout.getContentWidth();

        // The max widget span is the length N, such that NxN is the largest bounds that the widget
        // preview can be before applying the widget scaling
        mMinWidgetSpan = 1;
        mMaxWidgetSpan = 3;

        // The padding on the non-matched dimension for the default widget preview icons
        // (top + bottom)
        int iconSize = resources.getDimensionPixelSize(R.dimen.app_icon_size);
        mWidgetPreviewIconPaddedDimension =
            (int) (iconSize * (1 + (2 * sWidgetPreviewIconPaddingPercentage)));
    }

    @Override
    protected void init() {
        super.init();
        mCenterPagesVertically = false;

        Context context = getContext();
        Resources r = context.getResources();
        setDragSlopeThreshold(r.getInteger(R.integer.config_appsCustomizeDragSlopeThreshold)/100f);
    }

    /** Removes and returns the ResolveInfo with the specified ComponentName */
    private ResolveInfo removeResolveInfoWithComponentName(List<ResolveInfo> list,
            ComponentName cn) {
        Iterator<ResolveInfo> iter = list.iterator();
        while (iter.hasNext()) {
            ResolveInfo rinfo = iter.next();
            ActivityInfo info = rinfo.activityInfo;
            ComponentName c = new ComponentName(info.packageName, info.name);
            if (c.equals(cn)) {
                iter.remove();
                return rinfo;
            }
        }
        return null;
    }

    public void onPackagesUpdated() {
        // Get the list of widgets and shortcuts
        mWidgets.clear();
        mWidgets.addAll(AppWidgetManager.getInstance(mLauncher).getInstalledProviders());
        Intent shortcutsIntent = new Intent(Intent.ACTION_CREATE_SHORTCUT);
        mWidgets.addAll(mPackageManager.queryIntentActivities(shortcutsIntent, 0));
        Collections.sort(mWidgets,
                new LauncherModel.WidgetAndShortcutNameComparator(mPackageManager));

        // Get the list of wallpapers
        Intent wallpapersIntent = new Intent(Intent.ACTION_SET_WALLPAPER);
        mWallpapers = mPackageManager.queryIntentActivities(wallpapersIntent,
                PackageManager.GET_META_DATA);
        Collections.sort(mWallpapers,
                new LauncherModel.ShortcutNameComparator(mPackageManager));
        // Move Live Wallpapers to the front of the list
        Context c = getContext();
        ResolveInfo liveWallpapers = removeResolveInfoWithComponentName(mWallpapers,
            new ComponentName(c.getString(R.string.live_wallpaper_picker_package_name),
                c.getString(R.string.live_wallpaper_picker_class_name)));
        if (liveWallpapers != null) {
            mWallpapers.add(0, liveWallpapers);
        }
        // Move Wallpapers to the front of the list
        ResolveInfo wallpapers = removeResolveInfoWithComponentName(mWallpapers,
            new ComponentName(c.getPackageName(), WallpaperChooser.class.getName()));
        if (wallpapers != null) {
            mWallpapers.add(0, wallpapers);
        }
    }

    /**
     * Animates the given item onto the center of a home screen, and then scales the item to
     * look as though it's disappearing onto that screen.
     */
    private void animateItemOntoScreen(View dragView,
            final CellLayout layout, final ItemInfo info) {
        // On the phone, we only want to fade the widget preview out
        float[] position = new float[2];
        position[0] = layout.getWidth() / 2;
        position[1] = layout.getHeight() / 2;

        mLauncher.getWorkspace().mapPointFromChildToSelf(layout, position);

        int dragViewWidth = dragView.getMeasuredWidth();
        int dragViewHeight = dragView.getMeasuredHeight();
        float heightOffset = 0;
        float widthOffset = 0;

        if (dragView instanceof ImageView) {
            Drawable d = ((ImageView) dragView).getDrawable();
            int width = d.getIntrinsicWidth();
            int height = d.getIntrinsicHeight();

            if ((1.0 * width / height) >= (1.0f * dragViewWidth) / dragViewHeight) {
                float f = (dragViewWidth / (width * 1.0f));
                heightOffset = ANIMATION_SCALE * (dragViewHeight - f * height) / 2;
            } else {
                float f = (dragViewHeight / (height * 1.0f));
                widthOffset = ANIMATION_SCALE * (dragViewWidth - f * width) / 2;
            }
        }
        final float toX = position[0] - dragView.getMeasuredWidth() / 2 + widthOffset;
        final float toY = position[1] - dragView.getMeasuredHeight() / 2 + heightOffset;

        final DragLayer dragLayer = (DragLayer) mLauncher.findViewById(R.id.drag_layer);
        final View dragCopy = dragLayer.createDragView(dragView);
        dragCopy.setAlpha(1.0f);

        // Translate the item to the center of the appropriate home screen
        animateIntoPosition(dragCopy, toX, toY, null);

        // The drop-onto-screen animation begins a bit later, but ends at the same time.
        final int startDelay = TRANSLATE_ANIM_DURATION - DROP_ANIM_DURATION;

        // Scale down the icon and fade out the alpha
        animateDropOntoScreen(dragCopy, info, DROP_ANIM_DURATION, startDelay);
    }

    /**
     * Animation which scales the view down and animates its alpha, making it appear to disappear
     * onto a home screen.
     */
    private void animateDropOntoScreen(
            final View view, final ItemInfo info, int duration, int delay) {
        final DragLayer dragLayer = (DragLayer) mLauncher.findViewById(R.id.drag_layer);
        final CellLayout layout = mLauncher.getWorkspace().getCurrentDropLayout();

        ObjectAnimator anim = ObjectAnimator.ofPropertyValuesHolder(view,
                PropertyValuesHolder.ofFloat("alpha", 1.0f, 0.0f),
                PropertyValuesHolder.ofFloat("scaleX", ANIMATION_SCALE),
                PropertyValuesHolder.ofFloat("scaleY", ANIMATION_SCALE));
        anim.setInterpolator(new LinearInterpolator());
        if (delay > 0) {
            anim.setStartDelay(delay);
        }
        anim.setDuration(duration);
        anim.addListener(new AnimatorListenerAdapter() {
            public void onAnimationEnd(Animator animation) {
                dragLayer.removeView(view);
                mLauncher.addExternalItemToScreen(info, layout);
                info.dropPos = null;
            }
        });
        anim.start();
    }

    /**
     * Animates the x,y position of the view, and optionally execute a Runnable on animation end.
     */
    private void animateIntoPosition(
            View view, float toX, float toY, final Runnable endRunnable) {
        ObjectAnimator anim = ObjectAnimator.ofPropertyValuesHolder(view,
                PropertyValuesHolder.ofFloat("x", toX),
                PropertyValuesHolder.ofFloat("y", toY));
        anim.setInterpolator(new DecelerateInterpolator(2.5f));
        anim.setDuration(TRANSLATE_ANIM_DURATION);
        if (endRunnable != null) {
            anim.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    endRunnable.run();
                }
            });
        }
        anim.start();
    }

    @Override
    public void onClick(View v) {
        if (v instanceof PagedViewIcon) {
            // Animate some feedback to the click
            final ApplicationInfo appInfo = (ApplicationInfo) v.getTag();
            animateClickFeedback(v, new Runnable() {
                @Override
                public void run() {
                    mLauncher.startActivitySafely(appInfo.intent, appInfo);
                }
            });
        } else if (v instanceof PagedViewWidget) {
            if (v.getTag() instanceof ResolveInfo) {
                final ResolveInfo info = (ResolveInfo) v.getTag();
                if (mWallpapers.contains(info)) {
                    // Start the wallpaper picker
                    animateClickFeedback(v, new Runnable() {
                        @Override
                        public void run() {
                            // add the shortcut
                            Intent createWallpapersIntent = new Intent(Intent.ACTION_SET_WALLPAPER);
                            ComponentName name = new ComponentName(info.activityInfo.packageName,
                                    info.activityInfo.name);
                            createWallpapersIntent.setComponent(name);
                            mLauncher.processWallpaper(createWallpapersIntent);
                        }
                    });
                }
            } else {
                // Add the widget to the current workspace screen
                Workspace w = mLauncher.getWorkspace();
                int currentWorkspaceScreen = mLauncher.getCurrentWorkspaceScreen();
                final CellLayout cl = (CellLayout) w.getChildAt(currentWorkspaceScreen);
                final View dragView = v.findViewById(R.id.widget_preview);
                final ItemInfo itemInfo = (ItemInfo) v.getTag();
                animateClickFeedback(v, new Runnable() {
                    @Override
                    public void run() {
                        cl.calculateSpans(itemInfo);
                        if (cl.findCellForSpan(null, itemInfo.spanX, itemInfo.spanY)) {
                            if (LauncherApplication.isScreenLarge()) {
                                animateItemOntoScreen(dragView, cl, itemInfo);
                            } else {
                                mLauncher.addExternalItemToScreen(itemInfo, cl);
                                itemInfo.dropPos = null;
                            }

                            // Hide the pane so we can see the workspace we dropped on
                            mLauncher.showWorkspace(true);
                        } else {
                            mLauncher.showOutOfSpaceMessage();
                        }
                    }
                });
            }
        }
    }

    /*
     * PagedViewWithDraggableItems implementation
     */
    @Override
    protected void determineDraggingStart(android.view.MotionEvent ev) {
        // Disable dragging by pulling an app down for now.
    }
    private void beginDraggingApplication(View v) {
        // Make a copy of the ApplicationInfo
        ApplicationInfo appInfo = new ApplicationInfo((ApplicationInfo) v.getTag());

        // Show the uninstall button if the app is uninstallable.
        if ((appInfo.flags & ApplicationInfo.DOWNLOADED_FLAG) != 0) {
            DeleteZone allAppsDeleteZone = (DeleteZone)
                    mLauncher.findViewById(R.id.all_apps_delete_zone);
            allAppsDeleteZone.setDragAndDropEnabled(true);

            if ((appInfo.flags & ApplicationInfo.UPDATED_SYSTEM_APP_FLAG) != 0) {
                allAppsDeleteZone.setText(R.string.delete_zone_label_all_apps_system_app);
            } else {
                allAppsDeleteZone.setText(R.string.delete_zone_label_all_apps);
            }
        }

        // Show the info button
        ApplicationInfoDropTarget allAppsInfoButton =
            (ApplicationInfoDropTarget) mLauncher.findViewById(R.id.all_apps_info_target);
        allAppsInfoButton.setDragAndDropEnabled(true);

        // Compose the drag image (top compound drawable, index is 1)
        final TextView tv = (TextView) v;
        final Drawable icon = tv.getCompoundDrawables()[1];
        Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(),
                Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(b);
        c.translate((v.getWidth() - icon.getIntrinsicWidth()) / 2, v.getPaddingTop());
        icon.draw(c);

        // Compose the visible rect of the drag image
        Rect dragRect = null;
        if (v instanceof TextView) {
            int iconSize = getResources().getDimensionPixelSize(R.dimen.app_icon_size);
            int top = v.getPaddingTop();
            int left = (b.getWidth() - iconSize) / 2;
            int right = left + iconSize;
            int bottom = top + iconSize;
            dragRect = new Rect(left, top, right, bottom);
        }

        // Start the drag
        mLauncher.lockScreenOrientation();
        mLauncher.getWorkspace().onDragStartedWithItemSpans(1, 1, b);
        mDragController.startDrag(v, b, this, appInfo, DragController.DRAG_ACTION_COPY, dragRect);
        b.recycle();
    }
    private void beginDraggingWidget(View v) {
        // Get the widget preview as the drag representation
        ImageView image = (ImageView) v.findViewById(R.id.widget_preview);
        PendingAddItemInfo createItemInfo = (PendingAddItemInfo) v.getTag();

        // Compose the drag image
        Bitmap b;
        Drawable preview = image.getDrawable();
        int w = preview.getIntrinsicWidth();
        int h = preview.getIntrinsicHeight();
        if (createItemInfo instanceof PendingAddWidgetInfo) {
            PendingAddWidgetInfo createWidgetInfo = (PendingAddWidgetInfo) createItemInfo;
            int[] spanXY = CellLayout.rectToCell(getResources(),
                    createWidgetInfo.minWidth, createWidgetInfo.minHeight, null);
            createItemInfo.spanX = spanXY[0];
            createItemInfo.spanY = spanXY[1];

            b = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
            renderDrawableToBitmap(preview, b, 0, 0, w, h, 1, 1);
        } else {
            // Workaround for the fact that we don't keep the original ResolveInfo associated with
            // the shortcut around.  To get the icon, we just render the preview image (which has
            // the shortcut icon) to a new drag bitmap that clips the non-icon space.
            b = Bitmap.createBitmap(mWidgetPreviewIconPaddedDimension,
                    mWidgetPreviewIconPaddedDimension, Bitmap.Config.ARGB_8888);
            Canvas c = new Canvas(b);
            preview.draw(c);
            createItemInfo.spanX = createItemInfo.spanY = 1;
        }

        // Start the drag
        mLauncher.lockScreenOrientation();
        mLauncher.getWorkspace().onDragStartedWithItemSpans(createItemInfo.spanX,
                createItemInfo.spanY, b);
        mDragController.startDrag(image, b, this, createItemInfo,
                DragController.DRAG_ACTION_COPY, null);
        b.recycle();
    }
    @Override
    protected boolean beginDragging(View v) {
        if (!super.beginDragging(v)) return false;

        // Hide the pane so that the user can drop onto the workspace, we must do this first,
        // due to how the drop target layout is computed when we start dragging to the workspace.
        mLauncher.showWorkspace(true);

        if (v instanceof PagedViewIcon) {
            beginDraggingApplication(v);
        } else if (v instanceof PagedViewWidget) {
            beginDraggingWidget(v);
        }

        return true;
    }
    private void endDragging(boolean success) {
        post(new Runnable() {
            // Once the drag operation has fully completed, hence the post, we want to disable the
            // deleteZone and the appInfoButton in all apps, and re-enable the instance which
            // live in the workspace
            public void run() {
                // if onDestroy was called on Launcher, we might have already deleted the
                // all apps delete zone / info button, so check if they are null
                DeleteZone allAppsDeleteZone =
                        (DeleteZone) mLauncher.findViewById(R.id.all_apps_delete_zone);
                ApplicationInfoDropTarget allAppsInfoButton =
                    (ApplicationInfoDropTarget) mLauncher.findViewById(R.id.all_apps_info_target);

                if (allAppsDeleteZone != null) allAppsDeleteZone.setDragAndDropEnabled(false);
                if (allAppsInfoButton != null) allAppsInfoButton.setDragAndDropEnabled(false);
            }
        });
        mLauncher.getWorkspace().onDragStopped(success);
        mLauncher.unlockScreenOrientation();
    }

    /*
     * DragSource implementation
     */
    @Override
    public void onDragViewVisible() {}
    @Override
    public void onDropCompleted(View target, Object dragInfo, boolean success) {
        endDragging(success);

        // Display an error message if the drag failed due to there not being enough space on the
        // target layout we were dropping on.
        if (!success) {
            boolean showOutOfSpaceMessage = false;
            if (target instanceof Workspace) {
                int currentScreen = mLauncher.getCurrentWorkspaceScreen();
                Workspace workspace = (Workspace) target;
                CellLayout layout = (CellLayout) workspace.getChildAt(currentScreen);
                ItemInfo itemInfo = (ItemInfo) dragInfo;
                if (layout != null) {
                    layout.calculateSpans(itemInfo);
                    showOutOfSpaceMessage =
                            !layout.findCellForSpan(null, itemInfo.spanX, itemInfo.spanY);
                }
            }
            // TODO-APPS_CUSTOMIZE: We need to handle this for folders as well later.
            if (showOutOfSpaceMessage) {
                mLauncher.showOutOfSpaceMessage();
            }
        }
    }

    public void setContentType(ContentType type) {
        mContentType = type;
        setCurrentPage(0);
        invalidatePageData();
    }

    /*
     * Apps PagedView implementation
     */
    private void setVisibilityOnChildren(ViewGroup layout, int visibility) {
        int childCount = layout.getChildCount();
        for (int i = 0; i < childCount; ++i) {
            layout.getChildAt(i).setVisibility(visibility);
        }
    }
    private void setupPage(PagedViewCellLayout layout) {
        layout.setCellCount(mCellCountX, mCellCountY);
        layout.setGap(mPageLayoutWidthGap, mPageLayoutHeightGap);
        layout.setPadding(mPageLayoutPaddingLeft, mPageLayoutPaddingTop,
                mPageLayoutPaddingRight, mPageLayoutPaddingBottom);

        // Note: We force a measure here to get around the fact that when we do layout calculations
        // immediately after syncing, we don't have a proper width.  That said, we already know the
        // expected page width, so we can actually optimize by hiding all the TextView-based
        // children that are expensive to measure, and let that happen naturally later.
        setVisibilityOnChildren(layout, View.GONE);
        int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.AT_MOST);
        int heightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.AT_MOST);
        layout.setMinimumWidth(getPageContentWidth());
        layout.measure(widthSpec, heightSpec);
        setVisibilityOnChildren(layout, View.VISIBLE);
    }
    public void syncAppsPages() {
        // Ensure that we have the right number of pages
        Context context = getContext();
        int numPages = (int) Math.ceil((float) mApps.size() / (mCellCountX * mCellCountY));
        for (int i = 0; i < numPages; ++i) {
            PagedViewCellLayout layout = new PagedViewCellLayout(context);
            setupPage(layout);
            addView(layout);
        }
    }
    public void syncAppsPageItems(int page) {
        // ensure that we have the right number of items on the pages
        int numPages = getPageCount();
        int numCells = mCellCountX * mCellCountY;
        int startIndex = page * numCells;
        int endIndex = Math.min(startIndex + numCells, mApps.size());
        PagedViewCellLayout layout = (PagedViewCellLayout) getChildAt(page);
        layout.removeAllViewsOnPage();
        for (int i = startIndex; i < endIndex; ++i) {
            ApplicationInfo info = mApps.get(i);
            PagedViewIcon icon = (PagedViewIcon) mLayoutInflater.inflate(
                    R.layout.apps_customize_application, layout, false);
            icon.applyFromApplicationInfo(
                    info, mPageViewIconCache, true, isHardwareAccelerated() && (numPages > 1));
            icon.setOnClickListener(this);
            icon.setOnLongClickListener(this);
            icon.setOnTouchListener(this);

            int index = i - startIndex;
            int x = index % mCellCountX;
            int y = index / mCellCountX;
            layout.addViewToCellLayout(icon, -1, i, new PagedViewCellLayout.LayoutParams(x,y, 1,1));
        }
    }
    /*
     * Widgets PagedView implementation
     */
    private void setupPage(PagedViewGridLayout layout) {
        layout.setPadding(mPageLayoutPaddingLeft, mPageLayoutPaddingTop,
                mPageLayoutPaddingRight, mPageLayoutPaddingBottom);

        // Note: We force a measure here to get around the fact that when we do layout calculations
        // immediately after syncing, we don't have a proper width.  That said, we already know the
        // expected page width, so we can actually optimize by hiding all the TextView-based
        // children that are expensive to measure, and let that happen naturally later.
        setVisibilityOnChildren(layout, View.GONE);
        int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.AT_MOST);
        int heightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.AT_MOST);
        layout.setMinimumWidth(getPageContentWidth());
        layout.measure(widthSpec, heightSpec);
        setVisibilityOnChildren(layout, View.VISIBLE);
    }
    private void renderDrawableToBitmap(Drawable d, Bitmap bitmap, int x, int y, int w, int h,
            float scaleX, float scaleY) {
        Canvas c = new Canvas();
        if (bitmap != null) c.setBitmap(bitmap);
        c.save();
        c.scale(scaleX, scaleY);
        Rect oldBounds = d.copyBounds();
        d.setBounds(x, y, x + w, y + h);
        d.draw(c);
        d.setBounds(oldBounds); // Restore the bounds
        c.restore();
    }
    private FastBitmapDrawable getShortcutPreview(ResolveInfo info, int cellWidth, int cellHeight) {
        // Return the cached version if necessary
        Bitmap cachedBitmap = mWidgetPreviewCache.get(info);
        if (cachedBitmap != null) {
            return new FastBitmapDrawable(cachedBitmap);
        }

        Resources resources = mLauncher.getResources();
        int iconSize = resources.getDimensionPixelSize(R.dimen.app_icon_size);
        // We only need to make it wide enough so as not allow the preview to be scaled
        int expectedWidth = cellWidth;
        int expectedHeight = mWidgetPreviewIconPaddedDimension;
        int offset = (int) (iconSize * sWidgetPreviewIconPaddingPercentage);

        // Render the icon
        Bitmap preview = Bitmap.createBitmap(expectedWidth, expectedHeight, Config.ARGB_8888);
        Drawable icon = mIconCache.getFullResIcon(info, mPackageManager);
        renderDrawableToBitmap(mDefaultWidgetBackground, preview, 0, 0,
                mWidgetPreviewIconPaddedDimension, mWidgetPreviewIconPaddedDimension, 1f, 1f);
        renderDrawableToBitmap(icon, preview, offset, offset, iconSize, iconSize, 1f, 1f);
        FastBitmapDrawable iconDrawable = new FastBitmapDrawable(preview);
        iconDrawable.setBounds(0, 0, expectedWidth, expectedHeight);
        mWidgetPreviewCache.put(info, preview);
        return iconDrawable;
    }
    private FastBitmapDrawable getWidgetPreview(AppWidgetProviderInfo info, int cellHSpan,
            int cellVSpan, int cellWidth, int cellHeight) {
        // Return the cached version if necessary
        Bitmap cachedBitmap = mWidgetPreviewCache.get(info);
        if (cachedBitmap != null) {
            return new FastBitmapDrawable(cachedBitmap);
        }

        // Calculate the size of the drawable
        cellHSpan = Math.max(mMinWidgetSpan, Math.min(mMaxWidgetSpan, cellHSpan));
        cellVSpan = Math.max(mMinWidgetSpan, Math.min(mMaxWidgetSpan, cellVSpan));
        int expectedWidth = mWidgetSpacingLayout.estimateCellWidth(cellHSpan);
        int expectedHeight = mWidgetSpacingLayout.estimateCellHeight(cellVSpan);

        // Scale down the bitmap to fit the space
        float widgetPreviewScale = (float) cellWidth / expectedWidth;
        expectedWidth = (int) (widgetPreviewScale * expectedWidth);
        expectedHeight = (int) (widgetPreviewScale * expectedHeight);

        // Load the preview image if possible
        String packageName = info.provider.getPackageName();
        Drawable drawable = null;
        FastBitmapDrawable newDrawable = null;
        if (info.previewImage != 0) {
            drawable = mPackageManager.getDrawable(packageName, info.previewImage, null);
            if (drawable == null) {
                Log.w(LOG_TAG, "Can't load icon drawable 0x" + Integer.toHexString(info.icon)
                        + " for provider: " + info.provider);
            } else {
                // Scale down the preview to the dimensions we want
                int imageWidth = drawable.getIntrinsicWidth();
                int imageHeight = drawable.getIntrinsicHeight();
                float aspect = (float) imageWidth / imageHeight;
                int newWidth = imageWidth;
                int newHeight = imageHeight;
                if (aspect > 1f) {
                    newWidth = expectedWidth;
                    newHeight = (int) (imageHeight * ((float) expectedWidth / imageWidth));
                } else {
                    newHeight = expectedHeight;
                    newWidth = (int) (imageWidth * ((float) expectedHeight / imageHeight));
                }

                Bitmap preview = Bitmap.createBitmap(newWidth, newHeight, Config.ARGB_8888);
                renderDrawableToBitmap(drawable, preview, 0, 0, newWidth, newHeight, 1f, 1f);
                newDrawable = new FastBitmapDrawable(preview);
                newDrawable.setBounds(0, 0, newWidth, newHeight);
                mWidgetPreviewCache.put(info, preview);
            }
        }

        // Generate a preview image if we couldn't load one
        if (drawable == null) {
            Resources resources = mLauncher.getResources();
            int iconSize = resources.getDimensionPixelSize(R.dimen.app_icon_size);

            // Specify the dimensions of the bitmap
            if (info.minWidth >= info.minHeight) {
                expectedWidth = cellWidth;
                expectedHeight = mWidgetPreviewIconPaddedDimension;
            } else {
                // Note that in vertical widgets, we might not have enough space due to the text
                // label, so be conservative and use the width as a height bound
                expectedWidth = mWidgetPreviewIconPaddedDimension;
                expectedHeight = cellWidth;
            }

            Bitmap preview = Bitmap.createBitmap(expectedWidth, expectedHeight, Config.ARGB_8888);
            renderDrawableToBitmap(mDefaultWidgetBackground, preview, 0, 0, expectedWidth,
                    expectedHeight, 1f,1f);

            // Draw the icon in the top left corner
            try {
                Drawable icon = null;
                if (info.icon > 0) icon = mPackageManager.getDrawable(packageName, info.icon, null);
                if (icon == null) icon = resources.getDrawable(R.drawable.ic_launcher_application);

                int offset = (int) (iconSize * sWidgetPreviewIconPaddingPercentage);
                renderDrawableToBitmap(icon, preview, offset, offset, iconSize, iconSize, 1f, 1f);
            } catch (Resources.NotFoundException e) {}

            newDrawable = new FastBitmapDrawable(preview);
            newDrawable.setBounds(0, 0, expectedWidth, expectedHeight);
            mWidgetPreviewCache.put(info, preview);
        }
        return newDrawable;
    }
    public void syncWidgetPages() {
        // Ensure that we have the right number of pages
        Context context = getContext();
        int numWidgetsPerPage = mWidgetCountX * mWidgetCountY;
        int numPages = (int) Math.ceil(mWidgets.size() / (float) numWidgetsPerPage);
        for (int i = 0; i < numPages; ++i) {
            PagedViewGridLayout layout = new PagedViewGridLayout(context, mWidgetCountX,
                    mWidgetCountY);
            setupPage(layout);
            addView(layout);
        }
    }
    public void syncWidgetPageItems(int page) {
        PagedViewGridLayout layout = (PagedViewGridLayout) getChildAt(page);
        layout.removeAllViews();

        // Calculate the dimensions of each cell we are giving to each widget
        int numWidgetsPerPage = mWidgetCountX * mWidgetCountY;
        int offset = page * numWidgetsPerPage;
        int cellWidth = ((mWidgetSpacingLayout.getContentWidth() - mPageLayoutWidthGap
                - ((mWidgetCountX - 1) * mCellWidthGap)) / mWidgetCountX);
        int cellHeight = ((mWidgetSpacingLayout.getContentHeight() - mPageLayoutHeightGap
                - ((mWidgetCountY - 1) * mCellHeightGap)) / mWidgetCountY);
        for (int i = 0; i < Math.min(numWidgetsPerPage, mWidgets.size() - offset); ++i) {
            Object rawInfo = mWidgets.get(offset + i);
            PendingAddItemInfo createItemInfo = null;
            PagedViewWidget widget = (PagedViewWidget) mLayoutInflater.inflate(
                    R.layout.apps_customize_widget, layout, false);
            if (rawInfo instanceof AppWidgetProviderInfo) {
                // Fill in the widget information
                AppWidgetProviderInfo info = (AppWidgetProviderInfo) rawInfo;
                createItemInfo = new PendingAddWidgetInfo(info, null, null);
                final int[] cellSpans = CellLayout.rectToCell(getResources(), info.minWidth,
                        info.minHeight, null);
                FastBitmapDrawable preview = getWidgetPreview(info, cellSpans[0], cellSpans[1],
                        cellWidth, cellHeight);
                widget.applyFromAppWidgetProviderInfo(info, preview, -1, cellSpans, null, false);
                widget.setTag(createItemInfo);
            } else if (rawInfo instanceof ResolveInfo) {
                // Fill in the shortcuts information
                ResolveInfo info = (ResolveInfo) rawInfo;
                createItemInfo = new PendingAddItemInfo();
                createItemInfo.itemType = LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT;
                createItemInfo.componentName = new ComponentName(info.activityInfo.packageName,
                        info.activityInfo.name);
                FastBitmapDrawable preview = getShortcutPreview(info, cellWidth, cellHeight);
                widget.applyFromResolveInfo(mPackageManager, info, preview, null, false);
                widget.setTag(createItemInfo);
            }
            widget.setOnClickListener(this);
            widget.setOnLongClickListener(this);
            widget.setOnTouchListener(this);

            // Layout each widget
            int ix = i % mWidgetCountX;
            int iy = i / mWidgetCountX;
            PagedViewGridLayout.LayoutParams lp = new PagedViewGridLayout.LayoutParams(cellWidth,
                    cellHeight);
            lp.leftMargin = (ix * cellWidth) + (ix * mCellWidthGap);
            lp.topMargin = (iy * cellHeight) + (iy * mCellHeightGap);
            layout.addView(widget, lp);
        }
    }

    /*
     * This method fetches an xml file specified in the manifest identified by
     * WallpaperManager.WALLPAPER_PREVIEW_META_DATA). The xml file specifies
     * an image which will be used as the wallpaper preview for an activity
     * which responds to ACTION_SET_WALLPAPER. This image is returned and used
     * in the customize drawer.
     */
    private Drawable parseWallpaperPreviewXml(ResolveInfo ri) {
        ActivityInfo activityInfo = ri.activityInfo;
        XmlResourceParser parser = null;
        ComponentName component = new ComponentName(ri.activityInfo.packageName,
                ri.activityInfo.name);
        try {
            parser = activityInfo.loadXmlMetaData(mPackageManager,
                    WallpaperManager.WALLPAPER_PREVIEW_META_DATA);
            if (parser == null) {
                Slog.w(LOG_TAG, "No " + WallpaperManager.WALLPAPER_PREVIEW_META_DATA
                        + " meta-data for " + "wallpaper provider '" + component + '\'');
                return null;
            }

            AttributeSet attrs = Xml.asAttributeSet(parser);

            int type;
            while ((type=parser.next()) != XmlPullParser.END_DOCUMENT
                    && type != XmlPullParser.START_TAG) {
                // drain whitespace, comments, etc.
            }

            String nodeName = parser.getName();
            if (!"wallpaper-preview".equals(nodeName)) {
                Slog.w(LOG_TAG, "Meta-data does not start with wallpaper-preview tag for "
                        + "wallpaper provider '" + component + '\'');
                return null;
            }

            // If metaData was null, we would have returned earlier when getting
            // the parser No need to do the check here
            Resources res = mPackageManager.getResourcesForApplication(
                    activityInfo.applicationInfo);

            TypedArray sa = res.obtainAttributes(attrs,
                    com.android.internal.R.styleable.WallpaperPreviewInfo);

            TypedValue value = sa.peekValue(
                    com.android.internal.R.styleable.WallpaperPreviewInfo_staticWallpaperPreview);
            if (value == null) return null;

            return res.getDrawable(value.resourceId);
        } catch (Exception e) {
            Slog.w(LOG_TAG, "XML parsing failed for wallpaper provider '" + component + '\'', e);
            return null;
        } finally {
            if (parser != null) parser.close();
        }
    }
    private FastBitmapDrawable getWallpaperPreview(ResolveInfo info, int cellWidth, int cellHeight){
        // Return the cached version if necessary
        Bitmap cachedBitmap = mWidgetPreviewCache.get(info);
        if (cachedBitmap != null) {
            return new FastBitmapDrawable(cachedBitmap);
        }

        // Get the preview
        Resources resources = getContext().getResources();
        Drawable wallpaperPreview = parseWallpaperPreviewXml(info);
        Drawable wallpaperIcon = null;
        int expectedWidth;
        int expectedHeight;
        if (wallpaperPreview != null) {
            expectedWidth = wallpaperPreview.getIntrinsicWidth();
            expectedHeight = wallpaperPreview.getIntrinsicHeight();
        } else {
            wallpaperPreview = mDefaultWidgetBackground;
            expectedWidth = expectedHeight = Math.min(cellWidth, cellHeight);

            // Draw the icon in the top left corner
            String packageName = info.activityInfo.packageName;
            try {
                if (info.icon > 0) {
                    wallpaperIcon = mPackageManager.getDrawable(packageName, info.icon, null);
                }
                if (wallpaperIcon == null) {
                    wallpaperIcon = resources.getDrawable(R.drawable.ic_launcher_application);
                }
            } catch (Resources.NotFoundException e) {}
        }

        // Create the bitmap
        Bitmap preview = Bitmap.createBitmap(expectedWidth, expectedHeight, Config.ARGB_8888);
        renderDrawableToBitmap(wallpaperPreview, preview, 0, 0, expectedWidth, expectedHeight,
                1f, 1f);
        if (wallpaperIcon != null) {
            int iconSize = resources.getDimensionPixelSize(R.dimen.app_icon_size);
            int offset = (int) (iconSize * sWidgetPreviewIconPaddingPercentage);
            renderDrawableToBitmap(wallpaperIcon, preview, offset, offset, iconSize, iconSize,
                    1f, 1f);
        }

        FastBitmapDrawable previewDrawable = new FastBitmapDrawable(preview);
        previewDrawable.setBounds(0, 0, expectedWidth, expectedHeight);
        mWidgetPreviewCache.put(info, preview);
        return previewDrawable;
    }
    /*
     * Wallpapers PagedView implementation
     */
    public void syncWallpaperPages() {
        // Ensure that we have the right number of pages
        Context context = getContext();
        int numWidgetsPerPage = mWallpaperCountX * mWallpaperCountY;
        int numPages = (int) Math.ceil(mWallpapers.size() / (float) numWidgetsPerPage);
        for (int i = 0; i < numPages; ++i) {
            PagedViewGridLayout layout = new PagedViewGridLayout(context, mWallpaperCountX,
                    mWallpaperCountY);
            setupPage(layout);
            addView(layout);
        }
    }
    public void syncWallpaperPageItems(int page) {
        PagedViewGridLayout layout = (PagedViewGridLayout) getChildAt(page);
        layout.removeAllViews();

        // Calculate the dimensions of each cell we are giving to each widget
        int numWidgetsPerPage = mWallpaperCountX * mWallpaperCountY;
        int offset = page * numWidgetsPerPage;
        int cellWidth = ((mWidgetSpacingLayout.getContentWidth() - mPageLayoutWidthGap
                - ((mWallpaperCountX - 1) * mCellWidthGap)) / mWallpaperCountX);
        int cellHeight = ((mWidgetSpacingLayout.getContentHeight() - mPageLayoutHeightGap
                - ((mWallpaperCountY - 1) * mCellHeightGap)) / mWallpaperCountY);
        for (int i = 0; i < Math.min(numWidgetsPerPage, mWallpapers.size() - offset); ++i) {
            ResolveInfo info = mWallpapers.get(offset + i);
            PagedViewWidget widget = (PagedViewWidget) mLayoutInflater.inflate(
                    R.layout.apps_customize_wallpaper, layout, false);

            // Fill in the shortcuts information
            FastBitmapDrawable preview = getWallpaperPreview(info, cellWidth, cellHeight);
            widget.applyFromResolveInfo(mPackageManager, info, preview, null, false);
            widget.setTag(info);
            widget.setOnClickListener(this);
            widget.setOnLongClickListener(this);
            widget.setOnTouchListener(this);

            // Layout each widget
            int ix = i % mWallpaperCountX;
            int iy = i / mWallpaperCountX;
            PagedViewGridLayout.LayoutParams lp = new PagedViewGridLayout.LayoutParams(cellWidth,
                    cellHeight);
            lp.leftMargin = (ix * cellWidth) + (ix * mCellWidthGap);
            lp.topMargin = (iy * cellHeight) + (iy * mCellHeightGap);
            layout.addView(widget, lp);
        }
    }

    @Override
    public void syncPages() {
        removeAllViews();
        switch (mContentType) {
        case Applications:
            syncAppsPages();
            break;
        case Widgets:
            syncWidgetPages();
            break;
        case Wallpapers:
            syncWallpaperPages();
            break;
        }
    }
    @Override
    public void syncPageItems(int page) {
        switch (mContentType) {
        case Applications:
            syncAppsPageItems(page);
            break;
        case Widgets:
            syncWidgetPageItems(page);
            break;
        case Wallpapers:
            syncWallpaperPageItems(page);
            break;
        }
    }

    /**
     * Used by the parent to get the content width to set the tab bar to
     * @return
     */
    public int getPageContentWidth() {
        return mContentWidth;
    }

    /*
     * AllAppsView implementation
     */
    @Override
    public void setup(Launcher launcher, DragController dragController) {
        mLauncher = launcher;
        mDragController = dragController;
    }
    @Override
    public void zoom(float zoom, boolean animate) {
        // TODO-APPS_CUSTOMIZE: Call back to mLauncher.zoomed()
    }
    @Override
    public boolean isVisible() {
        return (getVisibility() == VISIBLE);
    }
    @Override
    public boolean isAnimating() {
        return false;
    }
    @Override
    public void setApps(ArrayList<ApplicationInfo> list) {
        mApps = list;
        Collections.sort(mApps, LauncherModel.APP_NAME_COMPARATOR);
        invalidatePageData();
    }
    private void addAppsWithoutInvalidate(ArrayList<ApplicationInfo> list) {
        // We add it in place, in alphabetical order
        int count = list.size();
        for (int i = 0; i < count; ++i) {
            ApplicationInfo info = list.get(i);
            int index = Collections.binarySearch(mApps, info, LauncherModel.APP_NAME_COMPARATOR);
            if (index < 0) {
                mApps.add(-(index + 1), info);
            }
        }
    }
    @Override
    public void addApps(ArrayList<ApplicationInfo> list) {
        addAppsWithoutInvalidate(list);
        invalidatePageData();
    }
    private int findAppByComponent(List<ApplicationInfo> list, ApplicationInfo item) {
        ComponentName removeComponent = item.intent.getComponent();
        int length = list.size();
        for (int i = 0; i < length; ++i) {
            ApplicationInfo info = list.get(i);
            if (info.intent.getComponent().equals(removeComponent)) {
                return i;
            }
        }
        return -1;
    }
    private void removeAppsWithoutInvalidate(ArrayList<ApplicationInfo> list) {
        // loop through all the apps and remove apps that have the same component
        int length = list.size();
        for (int i = 0; i < length; ++i) {
            ApplicationInfo info = list.get(i);
            int removeIndex = findAppByComponent(mApps, info);
            if (removeIndex > -1) {
                mApps.remove(removeIndex);
                mPageViewIconCache.removeOutline(new PagedViewIconCache.Key(info));
            }
        }
    }
    @Override
    public void removeApps(ArrayList<ApplicationInfo> list) {
        removeAppsWithoutInvalidate(list);
        invalidatePageData();
    }
    @Override
    public void updateApps(ArrayList<ApplicationInfo> list) {
        // We remove and re-add the updated applications list because it's properties may have
        // changed (ie. the title), and this will ensure that the items will be in their proper
        // place in the list.
        removeAppsWithoutInvalidate(list);
        addAppsWithoutInvalidate(list);
        invalidatePageData();
    }
    @Override
    public void reset() {
        if (mContentType != ContentType.Applications) {
            // Reset to the first page of the Apps pane
            AppsCustomizeTabHost tabs = (AppsCustomizeTabHost)
                    mLauncher.findViewById(R.id.apps_customize_pane);
            tabs.setCurrentTabByTag(tabs.getTabTagForContentType(ContentType.Applications));
        } else {
            setCurrentPage(0);
            invalidatePageData();
        }
    }
    @Override
    public void dumpState() {
        // TODO: Dump information related to current list of Applications, Widgets, etc.
        ApplicationInfo.dumpApplicationInfoList(LOG_TAG, "mApps", mApps);
        dumpAppWidgetProviderInfoList(LOG_TAG, "mWidgets", mWidgets);
    }
    private void dumpAppWidgetProviderInfoList(String tag, String label,
            List<Object> list) {
        Log.d(tag, label + " size=" + list.size());
        for (Object i: list) {
            if (i instanceof AppWidgetProviderInfo) {
                AppWidgetProviderInfo info = (AppWidgetProviderInfo) i;
                Log.d(tag, "   label=\"" + info.label + "\" previewImage=" + info.previewImage
                        + " resizeMode=" + info.resizeMode + " configure=" + info.configure
                        + " initialLayout=" + info.initialLayout
                        + " minWidth=" + info.minWidth + " minHeight=" + info.minHeight);
            } else if (i instanceof ResolveInfo) {
                ResolveInfo info = (ResolveInfo) i;
                Log.d(tag, "   label=\"" + info.loadLabel(mPackageManager) + "\" icon="
                        + info.icon);
            }
        }
    }
    @Override
    public void surrender() {
        // TODO: If we are in the middle of any process (ie. for holographic outlines, etc) we
        // should stop this now.
    }
}