src/com/android/launcher2/PagedViewGridLayout.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 android.content.Context;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.GridLayout;

/**
 * The grid based layout used strictly for the widget/wallpaper tab of the AppsCustomize pane
 */
public class PagedViewGridLayout extends GridLayout implements Page {
    static final String TAG = "PagedViewGridLayout";

    private int mCellCountX;
    private int mCellCountY;

    public PagedViewGridLayout(Context context, int cellCountX, int cellCountY) {
        super(context, null, 0);
        mCellCountX = cellCountX;
        mCellCountY = cellCountY;
        setColumnCount(mCellCountX);
    }

    int getCellCountX() {
        return mCellCountX;
    }
    int getCellCountY() {
        return mCellCountY;
    }

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // PagedView currently has issues with different-sized pages since it calculates the
        // offset of each page to scroll to before it updates the actual size of each page
        // (which can change depending on the content if the contents aren't a fixed size).
        // We work around this by having a minimum size on each widget page).
        int widthSpecSize = Math.min(getSuggestedMinimumWidth(),
                MeasureSpec.getSize(widthMeasureSpec));
        int widthSpecMode = MeasureSpec.EXACTLY;
        super.onMeasure(MeasureSpec.makeMeasureSpec(widthSpecSize, widthSpecMode),
                heightMeasureSpec);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        boolean result = super.onTouchEvent(event);
        int count = getPageChildCount();
        if (count > 0) {
            // We only intercept the touch if we are tapping in empty space after the final row
            View child = getChildOnPageAt(count - 1);
            int bottom = child.getBottom();
            result = result || (event.getY() < bottom);
        }
        return result;
    }

    @Override
    protected boolean onSetAlpha(int alpha) {
        return true;
    }

    @Override
    public void setAlpha(float alpha) {
        setChildrenAlpha(alpha);
        super.setAlpha(alpha);
    }

    private void setChildrenAlpha(float alpha) {
        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            getChildAt(i).setAlpha(alpha);
        }
    }

    @Override
    public void removeAllViewsOnPage() {
        removeAllViews();
    }

    @Override
    public void removeViewOnPageAt(int index) {
        removeViewAt(index);
    }

    @Override
    public int getPageChildCount() {
        return getChildCount();
    }

    @Override
    public View getChildOnPageAt(int i) {
        return getChildAt(i);
    }

    @Override
    public int indexOfChildOnPage(View v) {
        return indexOfChild(v);
    }

    public static class LayoutParams extends FrameLayout.LayoutParams {
        public LayoutParams(int width, int height) {
            super(width, height);
        }
    }
}