Question

我试图在Android上跟踪多点触控事件（我需要跟踪＆＃34;触及＆＃34;＆＃34;触摸＆＃34;每个手指）。问题是PointerId似乎不一致或者我在链接＆＃34; down＆＃34;活动到＆＃34; up＆＃34;因此，我错过了一些＆＃34; up＆＃34;事件

以下是我用来处理MotionEvents的代码：

int pointerIndex = me.getActionIndex();
int pointerId = me.getPointerId(pointerIndex);
final int action = me.getActionMasked();

switch (action)
{
case MotionEvent.ACTION_POINTER_DOWN:
{
    if (action == MotionEvent.ACTION_POINTER_DOWN)
    {
        System.out.println("ACTION_POINTER_DOWN Index: " + pointerIndex + ", ID: " + pointerId);
    }
}
case MotionEvent.ACTION_DOWN:
{
    if (action == MotionEvent.ACTION_DOWN)
    {
        System.out.println("Initial ACTION_DOWN Index: " + pointerIndex + ", ID: " + pointerId);
        pointerIndex = 0;
        pointerId = me.getPointerId(pointerIndex);
        System.out.println("ACTION_DOWN Index: " + pointerIndex + ", ID: " + pointerId);
    }
    if (!idPressed[pointerId])
    {
        idGenerator++;
        idOffset[pointerId] = idGenerator;
        mView.DoTouchEvent(0, mePos[pointerId * 2] - location[0], mePos[pointerId * 2 + 1] - location[1], idOffset[pointerId]);
        idPressed[pointerId] = true;
        //System.out.println("ACTION_DOWN Index: " + pointerIndex + ", ID: " + pointerId + " Gen: " + idOffset[pointerId]);
    }
    break;
}
    case MotionEvent.ACTION_POINTER_UP:
    {
        if (action == MotionEvent.ACTION_POINTER_UP)
        {
            System.out.println("ACTION_POINTER_UP Index: " + pointerIndex + ", ID: " + pointerId);
        }
    }
    case MotionEvent.ACTION_UP:
    {
        if (action == MotionEvent.ACTION_UP)
        {
            System.out.println("Initial ACTION_UP Index: " + pointerIndex + ", ID: " + pointerId);
            pointerIndex = 0;
            pointerId = me.getPointerId(pointerIndex);
            System.out.println("ACTION_UP Index: " + pointerIndex + ", ID: " + pointerId);
        }
        if (idPressed[pointerId])
        {
            mView.DoTouchEvent(1, me.getX(pointerIndex) - location[0], me.getY(pointerIndex) - location[1], idOffset[pointerId]);
            idPressed[pointerId] = false;
            //System.out.println("ACTION_UP Index: " + pointerIndex + ", ID: " + pointerId + " Gen: " + idOffset[pointerId]);
        }
        break;
    }

以下是使用上述代码记录的日志：

    08-24 12:13:32.603: I/System.out(3570): Initial ACTION_DOWN Index: 0, ID: 0
08-24 12:13:32.603: I/System.out(3570): ACTION_DOWN Index: 0, ID: 0
08-24 12:13:32.943: I/System.out(3570): ACTION_POINTER_DOWN Index: 1, ID: 1
08-24 12:13:32.943: I/System.out(3570): ACTION_POINTER_DOWN Index: 1, ID: 1
08-24 12:13:33.013: I/System.out(3570): ACTION_POINTER_UP Index: 1, ID: 1
08-24 12:13:33.013: I/System.out(3570): ACTION_POINTER_UP Index: 1, ID: 1
08-24 12:13:33.103: I/System.out(3570): ACTION_POINTER_DOWN Index: 1, ID: 1
08-24 12:13:33.103: I/System.out(3570): ACTION_POINTER_DOWN Index: 1, ID: 1
08-24 12:13:33.174: I/System.out(3570): ACTION_POINTER_UP Index: 1, ID: 1
08-24 12:13:33.174: I/System.out(3570): ACTION_POINTER_UP Index: 1, ID: 1
08-24 12:13:33.174: I/System.out(3570): ACTION_POINTER_UP Index: 1, ID: 1
08-24 12:13:33.214: I/System.out(3570): ACTION_POINTER_DOWN Index: 1, ID: 1
08-24 12:13:33.214: I/System.out(3570): ACTION_POINTER_DOWN Index: 1, ID: 1
08-24 12:13:34.115: I/System.out(3570): Initial ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): Initial ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): Initial ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): Initial ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): Initial ACTION_UP Index: 0, ID: 0
08-24 12:13:34.115: I/System.out(3570): ACTION_UP Index: 0, ID: 0

在这个日志的最后，我没有手指在屏幕上，但你可以看到没有＆＃34; up＆＃34; ID的事件：1。（我也不知道为什么我会一个接一个地获得相同类型的多个事件）。

我错过了什么吗？任何人都有任何想法？

谢谢， /科斯明

Answer 1

我终于找到了这个问题，我在这里发布了其他可能有同样问题的人，所以：问题是我收到时没有处理MotionEvent，而是我把它放在一个在下一个更新循环中排队并处理所有内容。问题是我实际上拿着一个指向MotionEvent的指针，并且在某些情况下有快速/多次触摸，这些对象的内容在处理循环之前被替换（很可能系统使用了一个MotionEvent对象池，所以一个对象将不时重复使用。）

了解android上的多点触控

1 个答案: