Question

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <Button
        android:id="@+id/button"
        android:layout_width="150dp"
        android:layout_height="150dp"
        />

    <TextView
        android:id="@+id/text_view"
        android:layout_width="150dp"
        android:layout_height="150dp"
        />
</LinearLayout>

View.OnTouchListener listener = new View.OnTouchListener() {
  @Override
  public boolean onTouch(View v, MotionEvent event) {
    String view = "";

    switch (v.getId()) {
      case R.id.button:
        view = "button";
        break;

      case R.id.text_view:
        view = "text_view";
        break;
    }

    Log.i(view, "event.getAction: " + event.getAction());

    return false;
  }
};

View btn = this.findViewById(R.id.button);
btn.setOnTouchListener(listener);

btn = this.findViewById(R.id.text_view);
btn.setOnTouchListener(listener);

输出：

button: event.getAction: 0
button: event.getAction: 1
button: event.getAction: 0
button: event.getAction: 2
button: event.getAction: 2
button: event.getAction: 2
button: event.getAction: 2
button: event.getAction: 2
button: event.getAction: 2
button: event.getAction: 2
button: event.getAction: 1
text_view: event.getAction: 0
text_view: event.getAction: 0
text_view: event.getAction: 0
text_view: event.getAction: 0
text_view: event.getAction: 0

问题：为什么要为Button发送ACTION_UP和ACTION_MOVE事件，而不是为TextView发送事件？

Answer 1

如果触摸了按钮，则默认活动。 dispatchTouchEvent （）会为ACTION_DOWN返回 true ，如果触摸了TextView，则返回 false 。这种差异导致问题中提到的行为。

为什么ACTION_UP对Button和TextView的工作方式不同？

1 个答案: