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

Android活动存储在活动堆栈中。回到以前的活动可能意味着两件事。

You opened the new activity from another activity with startActivityForResult. In that case you can just call the finishActivity() function from your code and it'll take you back to the previous activity. Keep track of the activity stack. Whenever you start a new activity with an intent you can specify an intent flag like FLAG_ACTIVITY_REORDER_TO_FRONT or FLAG_ACTIVITY_PREVIOUS_IS_TOP. You can use this to shuffle between the activities in your application. Haven't used them much though. Have a look at the flags here: http://developer.android.com/reference/android/content/Intent.html

正如注释中提到的，如果活动是用startActivity()打开的，那么可以用finish()关闭它。 如果你想使用向上按钮，你可以在onOptionsSelected(MenuItem item)方法中捕捉到，检查android.R.id.home的项目ID，而不是评论中提到的R.id.home。

我建议使用NavUtils.navigateUpFromSameTask()，它很简单，你可以从谷歌开发人员那里学习。希望我能帮到你!

试着活动#完成()。这或多或少是后退按钮默认的功能。

就在这个

super.onBackPressed();