Android重写系统返回键

1、方法一

@Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
                     //TODO something
                    return true;
              }
              return super.onKeyDown(keyCode, event);
 }

2、方法二

@Override
 public void onBackPressed() {
           //TODO something
          super.onBackPressed();
 }