@Override
 public boolean onOptionsItemSelected(MenuItem item) {
      int id = item.getItemId();

      if ( id == android.R.id.home ) {
          finish();
          return true;
      }

      return super.onOptionsItemSelected(item);
 }

尝试一下，它既可以在工具栏返回按钮作为硬件返回按钮。

您是否想要控制后退按钮的行为?您可以通过以下两种方法之一重写后退按钮(以转到特定的活动)。

Android 1.6及以下版本:

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

    return super.onKeyDown(keyCode, event);
}

或者如果你只支持android2.0或更高版本:

@Override
public void onBackPressed() {
    // do something on back.
    return;
}

详情请访问:http://android-developers.blogspot.com/2009/12/back-and-other-hard-keys-three-stories.html

就在这个

super.onBackPressed();

试着活动#完成()。这或多或少是后退按钮默认的功能。

有一些情况可以回到你之前的活动:

情况1:如果你想把结果带回你之前的活动，那么 ActivityA.java

 Intent intent = new Intent(ActivityA.this, FBHelperActivity.class);
               startActivityForResult(intent,2);

FBHelperActivity.java

 Intent returnIntent = new Intent();
 setResult(RESULT_OK, returnIntent);
 finish();

案例2:ActivityA——> FBHelperActivity---->ActivityA

ActivityA.java

 Intent intent = new Intent(ActivityA.this, FBHelperActivity.class);
               startActivity(intent);

FBHelperActivity.java

after getting of result call finish();
 By this way your second activity will finish and because 
 you did not call finish() in your first activity then
 automatic first activity is in back ground, will visible.

可以显式调用onBackPressed是最简单的方法 参考返回到上一个活动的详细信息