src/com/android/launcher3/LauncherAppState.java

/*
 * Copyright (C) 2013 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.launcher3;

import android.app.SearchManager;
import android.content.*;
import android.content.res.Configuration;
import android.database.ContentObserver;
import android.os.Handler;
import android.util.Log;

import java.lang.ref.WeakReference;

public class LauncherAppState {
    private static final String SHARED_PREFERENCES_KEY = "com.android.launcher3.prefs";

    private LauncherModel mModel;
    private IconCache mIconCache;
    private WidgetPreviewLoader.CacheDb mWidgetPreviewCacheDb;
    private boolean mIsScreenLarge;
    private float mScreenDensity;
    private int mLongPressTimeout = 300;

    private static WeakReference<LauncherProvider> sLauncherProvider;
    private static Context sContext;

    private static Object mLock = new Object();
    private static LauncherAppState INSTANCE;

    public static LauncherAppState getInstance() {
        if (INSTANCE == null) {
            INSTANCE = new LauncherAppState();
        }
        return INSTANCE;
    }

    public Context getContext() {
        return sContext;
    }

    public static void setApplicationContext(Context context) {
        if (sContext != null) {
            throw new IllegalStateException("setApplicationContext called twice! old=" + sContext + " new=" + context);
        }
        sContext = context.getApplicationContext();
    }

    private LauncherAppState() {
        if (sContext == null) {
            throw new IllegalStateException("LauncherAppState inited before app context set");
        }

        Log.v(Launcher.TAG, "LauncherAppState inited");

        if (sContext.getResources().getBoolean(R.bool.debug_memory_enabled)) {
            MemoryTracker.startTrackingMe(sContext, "L");
        }

        // set sIsScreenXLarge and mScreenDensity *before* creating icon cache
        mIsScreenLarge = sContext.getResources().getBoolean(R.bool.is_large_screen);
        mScreenDensity = sContext.getResources().getDisplayMetrics().density;

        mWidgetPreviewCacheDb = new WidgetPreviewLoader.CacheDb(sContext);
        mIconCache = new IconCache(sContext);
        mModel = new LauncherModel(this, mIconCache);

        // Register intent receivers
        IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
        filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
        filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
        filter.addDataScheme("package");
        sContext.registerReceiver(mModel, filter);
        filter = new IntentFilter();
        filter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
        filter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE);
        filter.addAction(Intent.ACTION_LOCALE_CHANGED);
        filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);
        sContext.registerReceiver(mModel, filter);
        filter = new IntentFilter();
        filter.addAction(SearchManager.INTENT_GLOBAL_SEARCH_ACTIVITY_CHANGED);
        sContext.registerReceiver(mModel, filter);
        filter = new IntentFilter();
        filter.addAction(SearchManager.INTENT_ACTION_SEARCHABLES_CHANGED);
        sContext.registerReceiver(mModel, filter);

        // Register for changes to the favorites
        ContentResolver resolver = sContext.getContentResolver();
        resolver.registerContentObserver(LauncherSettings.Favorites.CONTENT_URI, true,
                mFavoritesObserver);
    }

    /**
     * Call from Application.onTerminate(), which is not guaranteed to ever be called.
     */
    public void onTerminate() {
        sContext.unregisterReceiver(mModel);

        ContentResolver resolver = sContext.getContentResolver();
        resolver.unregisterContentObserver(mFavoritesObserver);
    }

    /**
     * Receives notifications whenever the user favorites have changed.
     */
    private final ContentObserver mFavoritesObserver = new ContentObserver(new Handler()) {
        @Override
        public void onChange(boolean selfChange) {
            // If the database has ever changed, then we really need to force a reload of the
            // workspace on the next load
            mModel.resetLoadedState(false, true);
            mModel.startLoaderFromBackground();
        }
    };

    LauncherModel setLauncher(Launcher launcher) {
        if (mModel == null) {
            throw new IllegalStateException("setLauncher() called before init()");
        }
        mModel.initialize(launcher);
        return mModel;
    }

    IconCache getIconCache() {
        return mIconCache;
    }

    LauncherModel getModel() {
        return mModel;
    }

    WidgetPreviewLoader.CacheDb getWidgetPreviewCacheDb() {
        return mWidgetPreviewCacheDb;
    }

    static void setLauncherProvider(LauncherProvider provider) {
        sLauncherProvider = new WeakReference<LauncherProvider>(provider);
    }

    static LauncherProvider getLauncherProvider() {
        return sLauncherProvider.get();
    }

    public static String getSharedPreferencesKey() {
        return SHARED_PREFERENCES_KEY;
    }

    public boolean isScreenLarge() {
        return mIsScreenLarge;
    }

    public static boolean isScreenLandscape(Context context) {
        return context.getResources().getConfiguration().orientation ==
            Configuration.ORIENTATION_LANDSCAPE;
    }

    public float getScreenDensity() {
        return mScreenDensity;
    }

    public int getLongPressTimeout() {
        return mLongPressTimeout;
    }
}