Draw the wallpaper chosen by the user

import android.app.WallpaperManager;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.graphics.Rect;

import android.graphics.drawable.Drawable;

import android.os.Handler;

import android.os.Message;

import android.os.SystemClock;

import android.service.wallpaper.WallpaperService;

import android.view.SurfaceHolder;

import android.content.Context;

import android.content.IntentFilter;

import android.content.Intent;

import android.content.BroadcastReceiver;

/**

 * Default built-in wallpaper that simply shows a static image.

 */

public class ImageWallpaper extends WallpaperService {

    public WallpaperManager mWallpaperManager;

    WallpaperManager mWallpaperManager;

    ImageWallpaper.DrawableEngine mEngine;

    private WallpaperObserver mReceiver;

    static final int MSG_DRAW = 1;

    @Override

    public void onCreate() {

        super.onCreate();

        mWallpaperManager = (WallpaperManager) getSystemService(WALLPAPER_SERVICE);

        IntentFilter filter = new IntentFilter(Intent.ACTION_WALLPAPER_CHANGED);

        mReceiver = new WallpaperObserver();

        registerReceiver(mReceiver, filter);

    }

    class MyEngine extends Engine {

        final Paint mTextPaint = new Paint();

        float mDensity;

        Drawable mBackground;

        long mAnimStartTime;

        boolean mAnimLarger;

    @Override

    public void onDestroy() {

        super.onDestroy();

        unregisterReceiver(mReceiver);

    }

        final Handler mHandler = new Handler() {

    public Engine onCreateEngine() {

        mEngine = new DrawableEngine();

        return mEngine;

    }

            @Override

            public void handleMessage(Message msg) {

                switch (msg.what) {

                    case MSG_DRAW:

                        drawFrame(true);

                        mHandler.sendEmptyMessage(MSG_DRAW);

                        break;

                    default:

                        super.handleMessage(msg);

    class WallpaperObserver extends BroadcastReceiver {

        public void onReceive(Context context, Intent intent) {

            mEngine.updateWallpaper();

        }

    }

        };

    class DrawableEngine extends Engine {

        private final Object mLock = new Object();

        Drawable mBackground;

        @Override

        public void onCreate(SurfaceHolder surfaceHolder) {

            super.onCreate(surfaceHolder);

            mBackground = mWallpaperManager.getDrawable();

            mTextPaint.setAntiAlias(true);

            mDensity = getResources().getDisplayMetrics().density;

            mTextPaint.setTextSize(30 * mDensity);

            mTextPaint.setShadowLayer(5*mDensity, 3*mDensity, 3*mDensity, 0xff000000);

            mTextPaint.setARGB(255, 255, 255, 255);

            mTextPaint.setTextAlign(Paint.Align.CENTER);

        }

        @Override

        public void onVisibilityChanged(boolean visible) {

            mHandler.removeMessages(MSG_DRAW);

            if (visible) {

                mHandler.sendEmptyMessage(MSG_DRAW);

                mAnimStartTime = SystemClock.uptimeMillis();

                mAnimLarger = true;

            } else {

                drawFrame(false);

            }

            drawFrame();

        }

        @Override

        public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {

            super.onSurfaceChanged(holder, format, width, height);

            drawFrame(false);

            drawFrame();

        }

        @Override

            super.onSurfaceDestroyed(holder);

        }

        void drawFrame(boolean drawText) {

        void drawFrame() {

            SurfaceHolder sh = getSurfaceHolder();

            Canvas c = null;

            try {

                c = sh.lockCanvas();

                if (c != null) {

                    final Rect frame = sh.getSurfaceFrame();

                    mBackground.setBounds(frame);

                    mBackground.draw(c);

                    if (drawText) {

                        // Figure out animation.

                        long now = SystemClock.uptimeMillis();

                        while (mAnimStartTime < (now-1000)) {

                            mAnimStartTime += 1000;

                            mAnimLarger = !mAnimLarger;

                        }

                        float size = (now-mAnimStartTime) / (float)1000;

                        if (!mAnimLarger) size = 1-size;

                        int alpha = (int)(255*(size*size));

                        mTextPaint.setARGB(alpha, 255, 255, 255);

                        mTextPaint.setShadowLayer(5*mDensity, 3*mDensity, 3*mDensity,

                                alpha<<24);

                        mTextPaint.setTextSize(100 * mDensity * size);

                        c.drawText("Am I live?",

                                frame.left + (frame.right-frame.left)/2,

                                frame.top + (frame.bottom-frame.top)/2, mTextPaint);

                    synchronized (mLock) {

                        final Drawable background = mBackground;

                        background.setBounds(frame);

                        background.draw(c);

                    }

                }

            } finally {

                if (c != null) sh.unlockCanvasAndPost(c);

            }

        }

    }

    @Override

    public void onCreate() {

        super.onCreate();

        mWallpaperManager = (WallpaperManager)getSystemService(WALLPAPER_SERVICE);

        void updateWallpaper() {

            synchronized (mLock) {

                mBackground = mWallpaperManager.getDrawable();

            }

        }

    public Engine onCreateEngine() {

        return new MyEngine();

    }

}