使用手势缩放 FrameLayout

Question

我正在尝试制作两个（或更多）可移动的 TextViews，并使用捏合缩放使整个集合具有可伸缩性。我有从 FrameLayout 扩展的自定义布局：

public class BublinkyLayout extends FrameLayout {
private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;
private float scale = 1;

public BublinkyLayout(Context context) {
    this(context, null, 0);
}

public BublinkyLayout(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public BublinkyLayout(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    setWillNotDraw(false);
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}

public void setScale(float scale) {
    this.scale = scale;
    invalidate();
}

public float getScale() {
    return this.scale;
}

@Override
protected void onDraw(Canvas canvas) {
    canvas.scale(scale, scale);
    super.onDraw(canvas);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    mScaleDetector.onTouchEvent(event);
    final int action = MotionEventCompat.getActionMasked(event);
    switch (action) {
        case MotionEvent.ACTION_MOVE:
            RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) this.getLayoutParams();
            this.setScale(mScaleFactor);
            this.setLayoutParams(layoutParams);
            this.invalidate();
            break;
    }
    return true;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        mScaleFactor *= detector.getScaleFactor();

        mScaleFactor = Math.max(0.3f, Math.min(mScaleFactor, 1.5f));

        invalidate();
        return true;
    }
}
}

但是当我使用“捏合缩放”和缩小时，子 TextView 没有与它们对齐的“触摸区域”（我可以触摸它们并移动它们的区域）。看起来布局是按比例缩放的，但面积还是一样的，这意味着我无法将它们从原始盒子中取出。

这是我用来移动 TextViews 的 OnTouchListener：

public class BublinkaOnTouchListener implements View.OnTouchListener {
private int _xDelta;
private int _yDelta;

@Override
public boolean onTouch(View view, MotionEvent event) {
    final int X = (int) event.getRawX();
    final int Y = (int) event.getRawY();
    switch (event.getAction() & MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN:
            FrameLayout.LayoutParams lParams = (FrameLayout.LayoutParams) view.getLayoutParams();
            _xDelta = X - lParams.leftMargin;
            _yDelta = Y - lParams.topMargin;
            break;
        case MotionEvent.ACTION_UP:
            break;
        case MotionEvent.ACTION_POINTER_DOWN:
            break;
        case MotionEvent.ACTION_POINTER_UP:
            break;
        case MotionEvent.ACTION_MOVE:
            FrameLayout.LayoutParams layoutParams = (FrameLayout.LayoutParams) view.getLayoutParams();
            layoutParams.leftMargin = X - _xDelta;
            layoutParams.topMargin = Y - _yDelta;
            layoutParams.rightMargin = -250;
            layoutParams.bottomMargin = -250;
            view.setLayoutParams(layoutParams);
            view.invalidate();
            break;
    }
    return true;
}
}

感谢您的每一个回答。

PS：英语不是我的母语，如有错误请见谅:)

Answer 1

找到了一个answer，主要解决了我的问题。

这不是我的最终解决方案，但它确实有助于解决这个问题。