判断是哪一个acitivity在活动Preferences的使用

@Overridepublic void onResume() {    Editor e = PreferenceManager.getDefaultSharedPreferences(this).edit();    e.putString("last_activity", getClass().getSimpleName());    e.commit();     super.onResume();}

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public class StartActivity extends Activity {    @Override      public void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);    // get last open Activity           String lastActivity = PreferenceManager.getDefaultSharedPreferences(this).getString("last_activity", "");                   if (last_activity == MyActivity2.getSimpleName()) {                              startActivityForResult(new Intent(this, MyActivity2.class));                             }                  else if (last_activity == MyActivity3.getSimpleName()) {                   startActivityForResult(new Intent(this, MyActivity3.class));                        }                    else {                          // assume default activity                         startActivityForResult(new Intent(this, MyActivity1.class));                               }             }          public void onActivityResult() {               // kill the activity if they go "back" to here        finish();    }}

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