Adding natural dragging effect to ImageView same as Facebook Messanger chat heads using Rebound library

Question

I am developing one app where I am dragging around my ImageView in Activity. I have configured Facebook Rebound library for spring animation which is originally used in Face

Answer 1

i have used above V class directly in Window-manager and it's work perfectly and chatHead move like facebook messenger.

public class ChatHeadService extends Service
{

    private LayoutInflater inflater;
    private WindowManager windowManager;

    private Point szWindow = new Point();


    @Override
    public void onCreate()
    {
    super.onCreate();
    Log.v(Utils.LogTag, "Start Service");
    }

    private
    void handleStart(){

         windowManager = (WindowManager)getSystemService(WINDOW_SERVICE);
        inflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);

        if (Build . VERSION . SDK_INT >= Build . VERSION_CODES . HONEYCOMB) {
            windowManager . getDefaultDisplay() . getSize(szWindow);
        } else {
            int w = windowManager . getDefaultDisplay() . getWidth();
            int h = windowManager . getDefaultDisplay() . getHeight();
            szWindow . set(w, h);
        }

        WindowManager . LayoutParams params = new WindowManager . LayoutParams(
            WindowManager . LayoutParams . WRAP_CONTENT,
            WindowManager . LayoutParams . WRAP_CONTENT,
            WindowManager . LayoutParams . TYPE_PHONE,
            WindowManager . LayoutParams . FLAG_NOT_FOCUSABLE |
            WindowManager . LayoutParams . FLAG_WATCH_OUTSIDE_TOUCH |
            WindowManager . LayoutParams . FLAG_LAYOUT_NO_LIMITS,
            PixelFormat . TRANSLUCENT
        );

        params . gravity = Gravity . TOP | Gravity . LEFT;
        params . x       = 50;
        params . y       = 100;

        V vImg = new V(this);

        windowManager . addView(vImg, params);


    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if (intent != null) {
            if (startId == Service . START_STICKY) {
                handleStart();
            }
        }

        return super . onStartCommand(intent, flags, startId);
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onDestroy(){
                super . onDestroy();
        if (windowManager != null) {
            // windowManager.removeView(chatHeadView);
        }
    }
}

Answer 2

what about this:

class V extends View implements SpringListener {
    private static final int NUM_ELEMS = 4;
    private Spring[] mXSprings = new Spring[NUM_ELEMS];
    private Spring[] mYSprings = new Spring[NUM_ELEMS];
    private Paint mPaint = new Paint();
    private Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

    public V(Context context) {
        super(context);
        SpringSystem ss = SpringSystem.create();

        Spring s;
        for (int i = 0; i < NUM_ELEMS; i++) {
            s = ss.createSpring();
            s.setSpringConfig(new MySpringConfig(200, i == 0? 8 : 15 + i * 2, i, true));
            s.addListener(this);
            mXSprings[i] = s;

            s = ss.createSpring();
            s.setSpringConfig(new MySpringConfig(200, i == 0? 8 : 15 + i * 2, i, false));
            s.addListener(this);
            mYSprings[i] = s;
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        mXSprings[0].setCurrentValue(w / 2);
        mYSprings[0].setCurrentValue(0);

        mXSprings[0].setEndValue(w / 2);
        mYSprings[0].setEndValue(h / 2);
    }

    @Override
    public void onSpringActivate(Spring s) {
    }

    @Override
    public void onSpringAtRest(Spring s) {
    }

    @Override
    public void onSpringEndStateChange(Spring s) {
    }

    @Override
    public void onSpringUpdate(Spring s) {
        MySpringConfig cfg = (MySpringConfig) s.getSpringConfig();
        if (cfg.index < NUM_ELEMS - 1) {
            Spring[] springs = cfg.horizontal? mXSprings : mYSprings;
            springs[cfg.index + 1].setEndValue(s.getCurrentValue());
        }
        if (cfg.index == 0) {
            invalidate();
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        mXSprings[0].setEndValue(event.getX());
        mYSprings[0].setEndValue(event.getY());
        return true;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        for (int i = NUM_ELEMS - 1; i >= 0; i--) {
            mPaint.setAlpha(i == 0? 255 : 192 - i * 128 / NUM_ELEMS);
            canvas.drawBitmap(mBitmap, 
                    (float) mXSprings[i].getCurrentValue() - mBitmap.getWidth() / 2,
                    (float) mYSprings[i].getCurrentValue() - mBitmap.getHeight() / 2,
                    mPaint);
        }
    }

    class MySpringConfig extends SpringConfig {
        int index;
        boolean horizontal;
        public MySpringConfig(double tension, double friction, int index, boolean horizontal) {
            super(tension, friction);
            this.index = index;
            this.horizontal = horizontal;
        }
    }
}