src/com/android/launcher2/LauncherApplication.java

/*
 * Copyright (C) 2008 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.app.Application;
import android.content.ContentResolver;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.Configuration;
import android.database.ContentObserver;
import android.os.Handler;

import java.lang.ref.WeakReference;

public class LauncherApplication extends Application {
    public LauncherModel mModel;
    public IconCache mIconCache;
    private static boolean sIsScreenLarge;
    private static float sScreenDensity;
    WeakReference<LauncherProvider> mLauncherProvider;

    @Override
    public void onCreate() {
        super.onCreate();

        // set sIsScreenXLarge and sScreenDensity *before* creating icon cache
        final int screenSize = getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK;
        sIsScreenLarge = screenSize == Configuration.SCREENLAYOUT_SIZE_LARGE ||
            screenSize == Configuration.SCREENLAYOUT_SIZE_XLARGE;
        sScreenDensity = getResources().getDisplayMetrics().density;

        mIconCache = new IconCache(this);
        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");
        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);
        registerReceiver(mModel, filter);

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

    /**
     * There's no guarantee that this function is ever called.
     */
    @Override
    public void onTerminate() {
        super.onTerminate();

        unregisterReceiver(mModel);

        ContentResolver resolver = 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) {
            mModel.startLoader(LauncherApplication.this, false);
        }
    };

    LauncherModel setLauncher(Launcher launcher) {
        mModel.initialize(launcher);
        return mModel;
    }

    IconCache getIconCache() {
        return mIconCache;
    }

    LauncherModel getModel() {
        return mModel;
    }

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

    LauncherProvider getLauncherProvider() {
        return mLauncherProvider.get();
    }

    public static boolean isScreenLarge() {
        return sIsScreenLarge;
    }

    public static float getScreenDensity() {
        return sScreenDensity;
    }
}