以下代码是我尝试用于多点触摸的代码。手指一设置正确,当我拖动手指时会四处移动。当我触摸并松开手指时,第二根手指会出现并消失,但它永远不会移动。知道怎么了吗?
我读过开发者博客,仍然不明白其中的问题是什么。
@Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getAction() & MotionEvent.ACTION_MASK;
int pointerIndex = (event.getAction() & MotionEvent.ACTION_POINTER_ID_MASK) >> MotionEvent.ACTION_POINTER_ID_SHIFT;
int pointerId = event.getPointerId(pointerIndex);
switch (action) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_DOWN:
if (pointerId == 0)
{
fingerOneDown = 1;
fingerOneX = event.getX(pointerIndex);
fingerOneY = event.getY(pointerIndex);
}
if (pointerId == 1)
{
fingerTwoDown = 1;
fingerTwoX = event.getX(pointerIndex);
fingerTwoY = event.getY(pointerIndex);
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
case MotionEvent.ACTION_CANCEL:
if (pointerId == 0)
{
fingerOneDown = 0;
fingerOneX = event.getX(pointerIndex);
fingerOneY = event.getY(pointerIndex);
}
if (pointerId == 1)
{
fingerTwoDown = 0;
fingerTwoX = event.getX(pointerIndex);
fingerTwoY = event.getY(pointerIndex);
}
break;
case MotionEvent.ACTION_MOVE:
if (pointerId == 0)
{
fingerOneDown = 1;
fingerOneX = event.getX(pointerIndex);
fingerOneY = event.getY(pointerIndex);
}
if (pointerId == 1)
{
fingerTwoDown = 1;
fingerTwoX = event.getX(pointerIndex);
fingerTwoY = event.getY(pointerIndex);
}
break;
}
return true;
}
永远不要忘记这一点。我修复了它。由于某种奇怪的原因,ACTION.MOVE事件总是作为pointerId为零。因此,您总是需要重新计算事件中的pointerId,如下所示:
case MotionEvent.ACTION_MOVE:
int pointerCount = event.getPointerCount();
for(int i = 0; i < pointerCount; ++i)
{
pointerIndex = i;
pointerId = event.getPointerId(pointerIndex);
Log.d("pointer id - move",Integer.toString(pointerId));
if(pointerId == 0)
{
fingerOneDown = 1;
fingerOneX = event.getX(pointerIndex);
fingerOneY = event.getY(pointerIndex);
}
if(pointerId == 1)
{
fingerTwoDown = 1;
fingerTwoX = event.getX(pointerIndex);
fingerTwoY = event.getY(pointerIndex);
}
}
break;