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Android example source code file (Home.java)

This example Android source code file (Home.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, applicationinfo, arraylist, broadcastreceiver, clippeddrawable, content, drawable, drawing, graphics, intent, ioexception, menu_search, menu_wallpaper_settings, override, packagemanager, paint, string, ui, view, xmlpullparserexception

The Home.java Android example source code

/*
 * Copyright (C) 2007 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.example.android.home;

import android.app.Activity;
import android.app.ActivityManager;
import android.app.SearchManager;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.ColorFilter;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.PaintDrawable;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.util.Xml;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.LayoutAnimationController;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.GridView;
import android.widget.TextView;

import java.io.IOException;
import java.io.FileReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

public class Home extends Activity {
    /**
     * Tag used for logging errors.
     */
    private static final String LOG_TAG = "Home";

    /**
     * Keys during freeze/thaw.
     */
    private static final String KEY_SAVE_GRID_OPENED = "grid.opened";

    private static final String DEFAULT_FAVORITES_PATH = "etc/favorites.xml";

    private static final String TAG_FAVORITES = "favorites";
    private static final String TAG_FAVORITE = "favorite";
    private static final String TAG_PACKAGE = "package";
    private static final String TAG_CLASS = "class";    

    // Identifiers for option menu items
    private static final int MENU_WALLPAPER_SETTINGS = Menu.FIRST + 1;
    private static final int MENU_SEARCH = MENU_WALLPAPER_SETTINGS + 1;
    private static final int MENU_SETTINGS = MENU_SEARCH + 1;

    /**
     * Maximum number of recent tasks to query.
     */
    private static final int MAX_RECENT_TASKS = 20;

    private static boolean mWallpaperChecked;
    private static ArrayList<ApplicationInfo> mApplications;
    private static LinkedList<ApplicationInfo> mFavorites;

    private final BroadcastReceiver mWallpaperReceiver = new WallpaperIntentReceiver();
    private final BroadcastReceiver mApplicationsReceiver = new ApplicationsIntentReceiver();

    private GridView mGrid;

    private LayoutAnimationController mShowLayoutAnimation;
    private LayoutAnimationController mHideLayoutAnimation;

    private boolean mBlockAnimation;

    private boolean mHomeDown;
    private boolean mBackDown;
    
    private View mShowApplications;
    private CheckBox mShowApplicationsCheck;

    private ApplicationsStackLayout mApplicationsStack;

    private Animation mGridEntry;
    private Animation mGridExit;
    
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        setDefaultKeyMode(DEFAULT_KEYS_SEARCH_LOCAL);

        setContentView(R.layout.home);

        registerIntentReceivers();

        setDefaultWallpaper();

        loadApplications(true);

        bindApplications();
        bindFavorites(true);
        bindRecents();
        bindButtons();

        mGridEntry = AnimationUtils.loadAnimation(this, R.anim.grid_entry);
        mGridExit = AnimationUtils.loadAnimation(this, R.anim.grid_exit);
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);

        // Close the menu
        if (Intent.ACTION_MAIN.equals(intent.getAction())) {
            getWindow().closeAllPanels();
        }
    }

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

        // Remove the callback for the cached drawables or we leak
        // the previous Home screen on orientation change
        final int count = mApplications.size();
        for (int i = 0; i < count; i++) {
            mApplications.get(i).icon.setCallback(null);
        }

        unregisterReceiver(mWallpaperReceiver);
        unregisterReceiver(mApplicationsReceiver);
    }

    @Override
    protected void onResume() {
        super.onResume();
        bindRecents();
    }
    
    @Override
    protected void onRestoreInstanceState(Bundle state) {
        super.onRestoreInstanceState(state);
        final boolean opened = state.getBoolean(KEY_SAVE_GRID_OPENED, false);
        if (opened) {
            showApplications(false);
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean(KEY_SAVE_GRID_OPENED, mGrid.getVisibility() == View.VISIBLE);
    }

    /**
     * Registers various intent receivers. The current implementation registers
     * only a wallpaper intent receiver to let other applications change the
     * wallpaper.
     */
    private void registerIntentReceivers() {
        IntentFilter filter = new IntentFilter(Intent.ACTION_WALLPAPER_CHANGED);
        registerReceiver(mWallpaperReceiver, filter);

        filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
        filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
        filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
        filter.addDataScheme("package");
        registerReceiver(mApplicationsReceiver, filter);
    }

    /**
     * Creates a new appplications adapter for the grid view and registers it.
     */
    private void bindApplications() {
        if (mGrid == null) {
            mGrid = (GridView) findViewById(R.id.all_apps);
        }
        mGrid.setAdapter(new ApplicationsAdapter(this, mApplications));
        mGrid.setSelection(0);

        if (mApplicationsStack == null) {
            mApplicationsStack = (ApplicationsStackLayout) findViewById(R.id.faves_and_recents);
        }
    }

    /**
     * Binds actions to the various buttons.
     */
    private void bindButtons() {
        mShowApplications = findViewById(R.id.show_all_apps);
        mShowApplications.setOnClickListener(new ShowApplications());
        mShowApplicationsCheck = (CheckBox) findViewById(R.id.show_all_apps_check);

        mGrid.setOnItemClickListener(new ApplicationLauncher());
    }

    /**
     * When no wallpaper was manually set, a default wallpaper is used instead.
     */
    private void setDefaultWallpaper() {
        if (!mWallpaperChecked) {
            Drawable wallpaper = peekWallpaper();
            if (wallpaper == null) {
                try {
                    clearWallpaper();
                } catch (IOException e) {
                    Log.e(LOG_TAG, "Failed to clear wallpaper " + e);
                }
            } else {
                getWindow().setBackgroundDrawable(new ClippedDrawable(wallpaper));
            }
            mWallpaperChecked = true;
        }
    }

    /**
     * Refreshes the favorite applications stacked over the all apps button.
     * The number of favorites depends on the user.
     */
    private void bindFavorites(boolean isLaunching) {
        if (!isLaunching || mFavorites == null) {

            if (mFavorites == null) {
                mFavorites = new LinkedList<ApplicationInfo>();
            } else {
                mFavorites.clear();
            }
            mApplicationsStack.setFavorites(mFavorites);            
            
            FileReader favReader;

            // Environment.getRootDirectory() is a fancy way of saying ANDROID_ROOT or "/system".
            final File favFile = new File(Environment.getRootDirectory(), DEFAULT_FAVORITES_PATH);
            try {
                favReader = new FileReader(favFile);
            } catch (FileNotFoundException e) {
                Log.e(LOG_TAG, "Couldn't find or open favorites file " + favFile);
                return;
            }

            final Intent intent = new Intent(Intent.ACTION_MAIN, null);
            intent.addCategory(Intent.CATEGORY_LAUNCHER);

            final PackageManager packageManager = getPackageManager();

            try {
                final XmlPullParser parser = Xml.newPullParser();
                parser.setInput(favReader);

                beginDocument(parser, TAG_FAVORITES);

                ApplicationInfo info;

                while (true) {
                    nextElement(parser);

                    String name = parser.getName();
                    if (!TAG_FAVORITE.equals(name)) {
                        break;
                    }

                    final String favoritePackage = parser.getAttributeValue(null, TAG_PACKAGE);
                    final String favoriteClass = parser.getAttributeValue(null, TAG_CLASS);

                    final ComponentName cn = new ComponentName(favoritePackage, favoriteClass);
                    intent.setComponent(cn);
                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                    info = getApplicationInfo(packageManager, intent);
                    if (info != null) {
                        info.intent = intent;
                        mFavorites.addFirst(info);
                    }
                }
            } catch (XmlPullParserException e) {
                Log.w(LOG_TAG, "Got exception parsing favorites.", e);
            } catch (IOException e) {
                Log.w(LOG_TAG, "Got exception parsing favorites.", e);
            }
        }

        mApplicationsStack.setFavorites(mFavorites);
    }

    private static void beginDocument(XmlPullParser parser, String firstElementName)
            throws XmlPullParserException, IOException {

        int type;
        while ((type = parser.next()) != XmlPullParser.START_TAG &&
                type != XmlPullParser.END_DOCUMENT) {
            // Empty
        }

        if (type != XmlPullParser.START_TAG) {
            throw new XmlPullParserException("No start tag found");
        }

        if (!parser.getName().equals(firstElementName)) {
            throw new XmlPullParserException("Unexpected start tag: found " + parser.getName() +
                    ", expected " + firstElementName);
        }
    }

    private static void nextElement(XmlPullParser parser) throws XmlPullParserException, IOException {
        int type;
        while ((type = parser.next()) != XmlPullParser.START_TAG &&
                type != XmlPullParser.END_DOCUMENT) {
            // Empty
        }
    }

    /**
     * Refreshes the recently launched applications stacked over the favorites. The number
     * of recents depends on how many favorites are present.
     */
    private void bindRecents() {
        final PackageManager manager = getPackageManager();
        final ActivityManager tasksManager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
        final List<ActivityManager.RecentTaskInfo> recentTasks = tasksManager.getRecentTasks(
                MAX_RECENT_TASKS, 0);

        final int count = recentTasks.size();
        final ArrayList<ApplicationInfo> recents = new ArrayList();

        for (int i = count - 1; i >= 0; i--) {
            final Intent intent = recentTasks.get(i).baseIntent;

            if (Intent.ACTION_MAIN.equals(intent.getAction()) &&
                    !intent.hasCategory(Intent.CATEGORY_HOME)) {

                ApplicationInfo info = getApplicationInfo(manager, intent);
                if (info != null) {
                    info.intent = intent;
                    if (!mFavorites.contains(info)) {
                        recents.add(info);
                    }
                }
            }
        }

        mApplicationsStack.setRecents(recents);
    }

    private static ApplicationInfo getApplicationInfo(PackageManager manager, Intent intent) {
        final ResolveInfo resolveInfo = manager.resolveActivity(intent, 0);

        if (resolveInfo == null) {
            return null;
        }

        final ApplicationInfo info = new ApplicationInfo();
        final ActivityInfo activityInfo = resolveInfo.activityInfo;
        info.icon = activityInfo.loadIcon(manager);
        if (info.title == null || info.title.length() == 0) {
            info.title = activityInfo.loadLabel(manager);
        }
        if (info.title == null) {
            info.title = "";
        }
        return info;
    }

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if (!hasFocus) {
            mBackDown = mHomeDown = false;
        }
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            switch (event.getKeyCode()) {
                case KeyEvent.KEYCODE_BACK:
                    mBackDown = true;
                    return true;
                case KeyEvent.KEYCODE_HOME:
                    mHomeDown = true;
                    return true;
            }
        } else if (event.getAction() == KeyEvent.ACTION_UP) {
            switch (event.getKeyCode()) {
                case KeyEvent.KEYCODE_BACK:
                    if (!event.isCanceled()) {
                        // Do BACK behavior.
                    }
                    mBackDown = true;
                    return true;
                case KeyEvent.KEYCODE_HOME:
                    if (!event.isCanceled()) {
                        // Do HOME behavior.
                    }
                    mHomeDown = true;
                    return true;
            }
        }

        return super.dispatchKeyEvent(event);
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);

        menu.add(0, MENU_WALLPAPER_SETTINGS, 0, R.string.menu_wallpaper)
                 .setIcon(android.R.drawable.ic_menu_gallery)
                 .setAlphabeticShortcut('W');
        menu.add(0, MENU_SEARCH, 0, R.string.menu_search)
                .setIcon(android.R.drawable.ic_search_category_default)
                .setAlphabeticShortcut(SearchManager.MENU_KEY);
        menu.add(0, MENU_SETTINGS, 0, R.string.menu_settings)
                .setIcon(android.R.drawable.ic_menu_preferences)
                .setIntent(new Intent(android.provider.Settings.ACTION_SETTINGS));

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case MENU_WALLPAPER_SETTINGS:
                startWallpaper();
                return true;
            case MENU_SEARCH:
                onSearchRequested();
                return true;
        }

        return super.onOptionsItemSelected(item);
    }

    private void startWallpaper() {
        final Intent pickWallpaper = new Intent(Intent.ACTION_SET_WALLPAPER);
        startActivity(Intent.createChooser(pickWallpaper, getString(R.string.menu_wallpaper)));
    }

    /**
     * Loads the list of installed applications in mApplications.
     */
    private void loadApplications(boolean isLaunching) {
        if (isLaunching && mApplications != null) {
            return;
        }

        PackageManager manager = getPackageManager();

        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

        final List<ResolveInfo> apps = manager.queryIntentActivities(mainIntent, 0);
        Collections.sort(apps, new ResolveInfo.DisplayNameComparator(manager));

        if (apps != null) {
            final int count = apps.size();

            if (mApplications == null) {
                mApplications = new ArrayList<ApplicationInfo>(count);
            }
            mApplications.clear();

            for (int i = 0; i < count; i++) {
                ApplicationInfo application = new ApplicationInfo();
                ResolveInfo info = apps.get(i);

                application.title = info.loadLabel(manager);
                application.setActivity(new ComponentName(
                        info.activityInfo.applicationInfo.packageName,
                        info.activityInfo.name),
                        Intent.FLAG_ACTIVITY_NEW_TASK
                        | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
                application.icon = info.activityInfo.loadIcon(manager);

                mApplications.add(application);
            }
        }
    }

    /**
     * Shows all of the applications by playing an animation on the grid.
     */
    private void showApplications(boolean animate) {
        if (mBlockAnimation) {
            return;
        }
        mBlockAnimation = true;

        mShowApplicationsCheck.toggle();

        if (mShowLayoutAnimation == null) {
            mShowLayoutAnimation = AnimationUtils.loadLayoutAnimation(
                    this, R.anim.show_applications);
        }

        // This enables a layout animation; if you uncomment this code, you need to
        // comment the line mGrid.startAnimation() below
//        mGrid.setLayoutAnimationListener(new ShowGrid());
//        mGrid.setLayoutAnimation(mShowLayoutAnimation);
//        mGrid.startLayoutAnimation();

        if (animate) {
            mGridEntry.setAnimationListener(new ShowGrid());
            mGrid.startAnimation(mGridEntry);
        }

        mGrid.setVisibility(View.VISIBLE);

        if (!animate) {
            mBlockAnimation = false;
        }

        // ViewDebug.startHierarchyTracing("Home", mGrid);
    }

    /**
     * Hides all of the applications by playing an animation on the grid.
     */
    private void hideApplications() {
        if (mBlockAnimation) {
            return;
        }
        mBlockAnimation = true;

        mShowApplicationsCheck.toggle();

        if (mHideLayoutAnimation == null) {
            mHideLayoutAnimation = AnimationUtils.loadLayoutAnimation(
                    this, R.anim.hide_applications);
        }

        mGridExit.setAnimationListener(new HideGrid());
        mGrid.startAnimation(mGridExit);
        mGrid.setVisibility(View.INVISIBLE);
        mShowApplications.requestFocus();

        // This enables a layout animation; if you uncomment this code, you need to
        // comment the line mGrid.startAnimation() above
//        mGrid.setLayoutAnimationListener(new HideGrid());
//        mGrid.setLayoutAnimation(mHideLayoutAnimation);
//        mGrid.startLayoutAnimation();
    }

    /**
     * Receives intents from other applications to change the wallpaper.
     */
    private class WallpaperIntentReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            getWindow().setBackgroundDrawable(new ClippedDrawable(getWallpaper()));
        }
    }

    /**
     * Receives notifications when applications are added/removed.
     */
    private class ApplicationsIntentReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            loadApplications(false);
            bindApplications();
            bindRecents();
            bindFavorites(false);
        }
    }

    /**
     * GridView adapter to show the list of all installed applications.
     */
    private class ApplicationsAdapter extends ArrayAdapter<ApplicationInfo> {
        private Rect mOldBounds = new Rect();

        public ApplicationsAdapter(Context context, ArrayList<ApplicationInfo> apps) {
            super(context, 0, apps);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            final ApplicationInfo info = mApplications.get(position);

            if (convertView == null) {
                final LayoutInflater inflater = getLayoutInflater();
                convertView = inflater.inflate(R.layout.application, parent, false);
            }

            Drawable icon = info.icon;

            if (!info.filtered) {
                //final Resources resources = getContext().getResources();
                int width = 42;//(int) resources.getDimension(android.R.dimen.app_icon_size);
                int height = 42;//(int) resources.getDimension(android.R.dimen.app_icon_size);

                final int iconWidth = icon.getIntrinsicWidth();
                final int iconHeight = icon.getIntrinsicHeight();

                if (icon instanceof PaintDrawable) {
                    PaintDrawable painter = (PaintDrawable) icon;
                    painter.setIntrinsicWidth(width);
                    painter.setIntrinsicHeight(height);
                }

                if (width > 0 && height > 0 && (width < iconWidth || height < iconHeight)) {
                    final float ratio = (float) iconWidth / iconHeight;

                    if (iconWidth > iconHeight) {
                        height = (int) (width / ratio);
                    } else if (iconHeight > iconWidth) {
                        width = (int) (height * ratio);
                    }

                    final Bitmap.Config c =
                            icon.getOpacity() != PixelFormat.OPAQUE ?
                                Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
                    final Bitmap thumb = Bitmap.createBitmap(width, height, c);
                    final Canvas canvas = new Canvas(thumb);
                    canvas.setDrawFilter(new PaintFlagsDrawFilter(Paint.DITHER_FLAG, 0));
                    // Copy the old bounds to restore them later
                    // If we were to do oldBounds = icon.getBounds(),
                    // the call to setBounds() that follows would
                    // change the same instance and we would lose the
                    // old bounds
                    mOldBounds.set(icon.getBounds());
                    icon.setBounds(0, 0, width, height);
                    icon.draw(canvas);
                    icon.setBounds(mOldBounds);
                    icon = info.icon = new BitmapDrawable(thumb);
                    info.filtered = true;
                }
            }

            final TextView textView = (TextView) convertView.findViewById(R.id.label);
            textView.setCompoundDrawablesWithIntrinsicBounds(null, icon, null, null);
            textView.setText(info.title);

            return convertView;
        }
    }

    /**
     * Shows and hides the applications grid view.
     */
    private class ShowApplications implements View.OnClickListener {
        public void onClick(View v) {
            if (mGrid.getVisibility() != View.VISIBLE) {
                showApplications(true);
            } else {
                hideApplications();
            }
        }
    }

    /**
     * Hides the applications grid when the layout animation is over.
     */
    private class HideGrid implements Animation.AnimationListener {
        public void onAnimationStart(Animation animation) {
        }

        public void onAnimationEnd(Animation animation) {
            mBlockAnimation = false;
        }

        public void onAnimationRepeat(Animation animation) {
        }
    }

    /**
     * Shows the applications grid when the layout animation is over.
     */
    private class ShowGrid implements Animation.AnimationListener {
        public void onAnimationStart(Animation animation) {
        }

        public void onAnimationEnd(Animation animation) {
            mBlockAnimation = false;
            // ViewDebug.stopHierarchyTracing();
        }

        public void onAnimationRepeat(Animation animation) {
        }
    }

    /**
     * Starts the selected activity/application in the grid view.
     */
    private class ApplicationLauncher implements AdapterView.OnItemClickListener {
        public void onItemClick(AdapterView parent, View v, int position, long id) {
            ApplicationInfo app = (ApplicationInfo) parent.getItemAtPosition(position);
            startActivity(app.intent);
        }
    }

    /**
     * When a drawable is attached to a View, the View gives the Drawable its dimensions
     * by calling Drawable.setBounds(). In this application, the View that draws the
     * wallpaper has the same size as the screen. However, the wallpaper might be larger
     * that the screen which means it will be automatically stretched. Because stretching
     * a bitmap while drawing it is very expensive, we use a ClippedDrawable instead.
     * This drawable simply draws another wallpaper but makes sure it is not stretched
     * by always giving it its intrinsic dimensions. If the wallpaper is larger than the
     * screen, it will simply get clipped but it won't impact performance.
     */
    private class ClippedDrawable extends Drawable {
        private final Drawable mWallpaper;

        public ClippedDrawable(Drawable wallpaper) {
            mWallpaper = wallpaper;
        }

        @Override
        public void setBounds(int left, int top, int right, int bottom) {
            super.setBounds(left, top, right, bottom);
            // Ensure the wallpaper is as large as it really is, to avoid stretching it
            // at drawing time
            mWallpaper.setBounds(left, top, left + mWallpaper.getIntrinsicWidth(),
                    top + mWallpaper.getIntrinsicHeight());
        }

        public void draw(Canvas canvas) {
            mWallpaper.draw(canvas);
        }

        public void setAlpha(int alpha) {
            mWallpaper.setAlpha(alpha);
        }

        public void setColorFilter(ColorFilter cf) {
            mWallpaper.setColorFilter(cf);
        }

        public int getOpacity() {
            return mWallpaper.getOpacity();
        }
    }
}

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