Arrastrar varias imágenes no funciona

Estoy trabajando en una aplicación que utiliza arrastrar y soltar en imágenes que puedo agregar cualquier número de imágenes en un diseño relativo. Puedo arrastrar imágenes, pero solo una a la vez. Una vez que añada la nueva imagen, todas las imágenes anteriores no son tocables.

public void addImage(Bitmap bmp) { ivtest= new ImageView(TabletActivity.this); if(bmp!=null) { ivtest.setImageBitmap(bmp); rlAddView.addView(ivtest, new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); bmp= null; } ivtest.setTag("sdjfjd"); ivtest.bringToFront(); ivtest.setScaleType(ScaleType.MATRIX); ivtest.setOnTouchListener(this); } 

Este es el código donde añadir una nueva imagen. El ivtest es una imagen global.

 public class TestImage extends View implements OnTouchListener { private ScaleGestureDetector mScaleDetector; private float mScaleFactor = 1.f; private Drawable mIcon; private float mLastTouchX; private static final int INVALID_POINTER_ID = -1; // The 'active pointer' is the one currently moving our object. private int mActivePointerId = INVALID_POINTER_ID; private float mPosX; private float mPosY; private float mLastTouchY; public TestImage(Context context, Drawable _micon) { super(context); mIcon =_micon; WindowManager wManager= (WindowManager)context.getSystemService(Context.WINDOW_SERVICE); mIcon.setBounds((int)getPivotX(), (int)getPivotY(), mIcon.getIntrinsicWidth(),mIcon.getIntrinsicWidth()); // setOnTouchListener(this); mScaleDetector = new ScaleGestureDetector(context, new ScaleListener()); } @Override public boolean onTouch(View view, MotionEvent ev) { mScaleDetector.onTouchEvent(ev); final int action = ev.getAction(); switch (action & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: { final float x = ev.getX(); final float y = ev.getY(); mLastTouchX = x; mLastTouchY = y; mActivePointerId = ev.getPointerId(0); break; } case MotionEvent.ACTION_MOVE: { final int pointerIndex = ev.findPointerIndex(mActivePointerId); final float x = ev.getX(pointerIndex); final float y = ev.getY(pointerIndex); // Only move if the ScaleGestureDetector isn't processing a gesture. if (!mScaleDetector.isInProgress()) { final float dx = x - mLastTouchX; final float dy = y - mLastTouchY; mPosX += dx; mPosY += dy; invalidate(); } mLastTouchX = x; mLastTouchY = y; break; } case MotionEvent.ACTION_UP: { mActivePointerId = INVALID_POINTER_ID; break; } case MotionEvent.ACTION_CANCEL: { mActivePointerId = INVALID_POINTER_ID; break; } case MotionEvent.ACTION_POINTER_UP: { final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; final int pointerId = ev.getPointerId(pointerIndex); if (pointerId == mActivePointerId) { // This was our active pointer going up. Choose a new // active pointer and adjust accordingly. final int newPointerIndex = pointerIndex == 0 ? 1 : 0; mLastTouchX = ev.getX(newPointerIndex); mLastTouchY = ev.getY(newPointerIndex); mActivePointerId = ev.getPointerId(newPointerIndex); } break; } } return true; } @Override public void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.save(); canvas.translate(mPosX, mPosY); canvas.scale(mScaleFactor, mScaleFactor); mIcon.setBounds(0, 0, mIcon.getIntrinsicWidth(),mIcon.getIntrinsicWidth()); mIcon.draw(canvas); canvas.restore(); } private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener { @Override public boolean onScale(ScaleGestureDetector detector) { mScaleFactor *= detector.getScaleFactor(); // Don't let the object get too small or too large. mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 5.0f)); invalidate(); return true; } } 

}