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

如果你想去只是想去以前的活动使用

finish();

OR

onBackPressed();

如果你想去第二个活动或以下使用以下:

intent = new Intent(MyFourthActivity.this , MySecondActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
//Bundle is optional
Bundle bundle = new Bundle();
bundle.putString("MyValue1", val1);
intent.putExtras(bundle);
//end Bundle
startActivity(intent);

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

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

你可以试试这个:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {

        finish();
        return true;
    }
    return super.onKeyDown(keyCode, event);
}