How to use onSaveInstanceState() and onRestoreInstanceState()?

Question

I am trying to save data across orientation changes. As demonstrated in the code below, I use onSaveInstanceState() and onRestoreInstanceState(). I try to get the saved value and I check if it is the correct value in onRestoreInstanceState(). But when I try to use the new value in onCreate(), I don't have the new value but the old one.

protected void onSaveInstanceState(Bundle outState) {         super.onSaveInstanceState(outState);         outState.putString("TEXT", user);      } protected void onRestoreInstanceState(Bundle savedInstanceState) {     super.onRestoreInstanceState(savedInstanceState);     savedUser = savedInstanceState.getString("TEXT");     Log.d("enregistred value", savedUser);  }    public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);          int display_mode = getResources().getConfiguration().orientation;          if (display_mode == 1) {              setContentView(R.layout.main_grid);             mGrid = (GridView) findViewById(R.id.gridview);             mGrid.setColumnWidth(95);             mGrid.setVisibility(0x00000000);             // mGrid.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);          } else {             setContentView(R.layout.main_grid_land);             mGrid = (GridView) findViewById(R.id.gridview);             mGrid.setColumnWidth(95);             Log.d("Mode", "land");             // mGrid.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);          }         Log.d("savedUser", savedUser);         if (savedUser.equals("admin")) { //value 0             adapter.setApps(appManager.getApplications());         } else if (savedUser.equals("prof")) { //value 1             adapter.setApps(appManager.getTeacherApplications());         } else {// default value             appManager = new ApplicationManager(this, getPackageManager());             appManager.loadApplications(true);             bindApplications();         } } 

Answer 1

When your activity is recreated after it was previously destroyed, you can recover your saved state from the Bundle that the system passes your activity. Both the onCreate() and onRestoreInstanceState() callback methods receive the same Bundle that contains the instance state information.

Because the onCreate() method is called whether the system is creating a new instance of your activity or recreating a previous one, you must check whether the state Bundle is null before you attempt to read it. If it is null, then the system is creating a new instance of the activity, instead of restoring a previous one that was destroyed.

static final String STATE_USER = "user"; private String mUser;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     // Check whether we're recreating a previously destroyed instance     if (savedInstanceState != null) {         // Restore value of members from saved state         mUser = savedInstanceState.getString(STATE_USER);     } else {         // Probably initialize members with default values for a new instance         mUser = "NewUser";     } }  @Override public void onSaveInstanceState(Bundle savedInstanceState) {     savedInstanceState.putString(STATE_USER, mUser);     // Always call the superclass so it can save the view hierarchy state     super.onSaveInstanceState(savedInstanceState); } 

http://developer.android.com/training/basics/activity-lifecycle/recreating.html