android - 拖动多个图像不起作用

Question

我正在开发一个在图像上使用拖放的应用程序，我可以在相对布局中添加任意数量的图像。我可以拖动图像，但一次只能拖动一个。添加新图像后，所有以前的图像都不可触摸。

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);
}

这是我添加新图片的代码。 ivtest 是一个全局 imageView。

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;
    }
}

}

Answer 1

我找到了答案。这是一个在 View 上实现拖放、旋转、缩放的库项目。 http://code.google.com/p/android-multitouch-controller/