Android ACTION_UP 和 ACTION_DOWN 同时调用

Question

我正在使用触摸事件进行输入。MotionEvent.ACTION_DOWN 和 MotionEvent.ACTION_UP 都会在按下期间调用。当我的手指从表面抬起时，它应该只调用 ACTION_UP 。他们同时被召唤。请参阅以下代码和 logcat 输出。

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    public boolean onTouchEvent(MotionEvent e) {\n    // MotionEvent reports input details from the touch screen\n    // and other input controls. In this case, you are only\n    // interested in events where the touch position changed.\n\n    float x = e.getX();\n    float y = e.getY();\n\n    switch (e.getAction()) {\n        case MotionEvent.ACTION_DOWN:\n            mRenderer.scanButtonsDown(x, y);\n\n            Log.i("Touch", "Action Down Case");\n\n        case MotionEvent.ACTION_UP:\n            mRenderer.scanButtonsUp(x, y);\n\n            Log.i("Touch", "Action Up Case");\n\n    }\n\n    mPreviousX = x;\n    mPreviousY = y;\n    return true;\n}\n

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这是 logcat 输出：

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09-01 14:58:24.801    4683-4683/nf.co.av_club.opengl I/Touch\xef\xb9\x95 Action Down Case\n09-01 14:58:24.811    4683-4683/nf.co.av_club.opengl I/Touch\xef\xb9\x95 Action Up Case\n09-01 14:58:24.961    4683-4683/nf.co.av_club.opengl I/Touch\xef\xb9\x95 Action Up Case\n

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之前的 logcat 在按一次屏幕时会生成一个向下的情况和两个向上的情况。现在我将进行长时间的记者采访。

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09-01 14:58:37.113    4683-4683/nf.co.av_club.opengl I/Touch\xef\xb9\x95 Action Down Case\n09-01 14:58:37.123    4683-4683/nf.co.av_club.opengl I/Touch\xef\xb9\x95 Action Up Case\n09-01 14:58:41.097    4683-4683/nf.co.av_club.opengl I/Touch\xef\xb9\x95 Action Up Case\n

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看到时间戳了吗？Down 和 Up 同时调用。两秒钟后，当我真正将手指从平板电脑上移开时，它会再次被调用。有人有建议吗？

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Answer 1

你错过了break;每个结尾处的case。请像下面这样操作。

switch (e.getAction()) {
    case MotionEvent.ACTION_DOWN:
        mRenderer.scanButtonsDown(x, y);
        Log.i("Touch", "Action Down Case");
        break; //add this line

    case MotionEvent.ACTION_UP:
        mRenderer.scanButtonsUp(x, y);
        Log.i("Touch", "Action Up Case");
        break; //and this line

}