返回键与moveTaskToBack的使用

public class TestActivity extends Activity {
  //...
  // Working for all API levels
  @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
      moveTaskToBack(true);
    }
    return super.onKeyDown(keyCode, event);
  }
        
  // Alternative variant for API 5 and higher
  @Override
  public void onBackPressed() {
    moveTaskToBack(true);//移动任务包含此活动活动栈的后面。在任务活动的顺序不变（如为false，退出）
  }
}