Android Live Wallpaper

Xin chào mọi người, hôm nay mình sẽ viết bài chia sẻ về live wallpaper trong android. vậy live wallpaper là gì: nó chính là màn hình home của thiết bị android của bạn, nghĩa là bạn sẽ tạo ra một màn hình riêng của mình.

Tạo một wallpaper

1. Trong res/xml tạo 1 file mywallpaper.xml

<?xml version="1.0" encoding="UTF-8"?>
<wallpaper
xmlns:android="http://schemas.android.com/apk/res/android"
android:thumbnail="@drawable/icon"
android:description="@string/wallpaper_description"
android:settingsActivity="de.vogella.android.wallpaper.MyPreferencesActivity"/>

2. Tạo class để lưu lại giá trị chúng ta vẽ

public class MyPoint {
    String text;
    private int x;
    private int y;

    public MyPoint(String text, int x, int y) {
        this.text = text;
        this.x = x;
        this.y = y;
    }
}

3. Tạo 1 layout mới trong res/xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference android:key="touch"
        android:title="Enable Touch"></CheckBoxPreference>
    <EditTextPreference android:key="numberOfCircles"
        android:title="Number of Circles"></EditTextPreference>
</PreferenceScreen>

4.Tạo activity mới

public class MyPreferencesActivity extends PreferenceActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.prefs);

        // add a validator to the "numberofCircles" preference so that it only
        // accepts numbers
        Preference circlePreference = getPreferenceScreen().findPreference(
                "numberOfCircles");

        // add the validator
        circlePreference.setOnPreferenceChangeListener(numberCheckListener);
    }

    /**
     * Checks that a preference is a valid numerical value
     */
    Preference.OnPreferenceChangeListener numberCheckListener = new OnPreferenceChangeListener() {

        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            // check that the string is an integer
            if (newValue != null && newValue.toString().length() > 0
                    && newValue.toString().matches("\\d*")) {
                return true;
            }
            // If now create a message to the user
            Toast.makeText(MyPreferencesActivity.this, "Invalid Input",
                    Toast.LENGTH_SHORT).show();
            return false;
        }
    };

}

5. Custom wallpaper

public class MyWallpaperService extends WallpaperService {

    @Override
    public Engine onCreateEngine() {
        return new MyWallpaperEngine();
    }

    private class MyWallpaperEngine extends Engine {
        private final Handler handler = new Handler();
        private final Runnable drawRunner = new Runnable() {
            @Override
            public void run() {
                draw();
            }

        };
        private List<MyPoint> circles;
        private Paint paint = new Paint();
        private int width;
        int height;
        private boolean visible = true;
        private int maxNumber;
        private boolean touchEnabled;

        public MyWallpaperEngine() {
            SharedPreferences prefs = PreferenceManager
                    .getDefaultSharedPreferences(MyWallpaperService.this);
            maxNumber = Integer
                    .valueOf(prefs.getString("numberOfCircles", "4"));
            touchEnabled = prefs.getBoolean("touch", false);
            circles = new ArrayList<MyPoint>();
            paint.setAntiAlias(true);
            paint.setColor(Color.WHITE);
            paint.setStyle(Paint.Style.STROKE);
            paint.setStrokeJoin(Paint.Join.ROUND);
            paint.setStrokeWidth(10f);
            handler.post(drawRunner);
        }

        @Override
        public void onVisibilityChanged(boolean visible) {
            this.visible = visible;
            if (visible) {
                handler.post(drawRunner);
            } else {
                handler.removeCallbacks(drawRunner);
            }
        }



}
@Override
        public void onSurfaceDestroyed(SurfaceHolder holder) {
            super.onSurfaceDestroyed(holder);
            this.visible = false;
            handler.removeCallbacks(drawRunner);
        }

        @Override
        public void onSurfaceChanged(SurfaceHolder holder, int format,
                int width, int height) {
            this.width = width;
            this.height = height;
            super.onSurfaceChanged(holder, format, width, height);
        }

        @Override
        public void onTouchEvent(MotionEvent event) {
            if (touchEnabled) {

                float x = event.getX();
                float y = event.getY();
                SurfaceHolder holder = getSurfaceHolder();
                Canvas canvas = null;
                try {
                    canvas = holder.lockCanvas();
                    if (canvas != null) {
                        canvas.drawColor(Color.BLACK);
                        circles.clear();
                        circles.add(new MyPoint(
                                String.valueOf(circles.size() + 1), x, y));
                        drawCircles(canvas, circles);

                    }
                } finally {
                    if (canvas != null)
                        holder.unlockCanvasAndPost(canvas);
                }
                super.onTouchEvent(event);
            }
        }

        private void draw() {
            SurfaceHolder holder = getSurfaceHolder();
            Canvas canvas = null;
            try {
                canvas = holder.lockCanvas();
                if (canvas != null) {
                    if (circles.size() >= maxNumber) {
                        circles.clear();
                    }
                    int x = (int) (width * Math.random());
                    int y = (int) (height * Math.random());
                    circles.add(new MyPoint(String.valueOf(circles.size() + 1),
                            x, y));
                    drawCircles(canvas, circles);
                }
            } finally {
                if (canvas != null)
                    holder.unlockCanvasAndPost(canvas);
            }
            handler.removeCallbacks(drawRunner);
            if (visible) {
                handler.postDelayed(drawRunner, 5000);
            }
        }

        // Surface view requires that all elements are drawn completely
        private void drawCircles(Canvas canvas, List<MyPoint> circles) {
            canvas.drawColor(Color.BLACK);
            for (MyPoint point : circles) {
                canvas.drawCircle(point.x, point.y, 20.0f, paint);
            }
        }
    }

6. Sử dụng wallpaper của chính mình tạo ra thôi

public class SetWallpaperActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void onClick(View view) {
        Intent intent = new Intent(
                WallpaperManager.ACTION_CHANGE_LIVE_WALLPAPER);
        intent.putExtra(WallpaperManager.EXTRA_LIVE_WALLPAPER_COMPONENT,
                new ComponentName(this, MyWallpaperService.class));
        startActivity(intent);
    }
}

Và kết quả chúng ta đạt được:

Bài viết được tham khảo tại: http://www.vogella.com/tutorials/AndroidLiveWallpaper/article.html Rất mong được sự góp ý của các bạn !