在Android中按下向左，向右，向上，向下箭头时，onKeyDown不会触发

Question

InputMethodService中的OnKeyDown回调适用于许多硬件键盘按钮，但它不会使用向左，向右，向上，向下箭头触发。我怎么处理呢？

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Answer 1

您是否看过developer documentation on handling key events?您可以尝试onKeyDown或onKeyUp只接收一个事件并打印出keyCode以查看收到的内容：

@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
  Log.i("your tag", "Keycode: " + keyCode);
  switch (keyCode) {
    case KeyEvent.KEYCODE_DPAD_LEFT:
        leftKeyClick();
        return true;
    case KeyEvent.KEYCODE_DPAD_RIGHT:
        rightKeyClick();
        return true;
    case KeyEvent.KEYCODE_DPAD_UP:
        upKeyClick();
        return true;
    case KeyEvent.KEYCODE_DPAD_DOWN:
        downKeyClick();
        return true;
    default:
        return super.onKeyUp(keyCode, event);
  }
}

KeyEvent Object reference gives more details.如果您仍未检测到箭头键，则可能需要覆盖视图的onKeyDown或onKeyUp方法this similar question might be useful.