CODEWITHSUNDEEP
androidmobile
AlanSTACK
AlanSTACK

Reputation: 6065

What is saved automatically for onSaveInstanceState()? And what is not?

so recent android dev convert here.

I see in online tutorials people mention that we need to use onSaveInstanceState() What they dont mention is when we should use it.

Obviously a TextView object's internal text (or a button's internal text) does not need to be saved.

What does need to be saved? Do EditText contents get automatically saved?

What types of data should we save/What should we not

Upvotes: 1

Views: 362

Answers (1)

Cyrus
Cyrus

Reputation: 9425

Save your activity state As your activity begins to stop, the system calls the onSaveInstanceState() method so your activity can save state information with a collection of key-value pairs. The default implementation of this method saves transient information about the state of the activity's view hierarchy, such as the text in an EditText widget or the scroll position of a ListView widget. Your app should implement the onSaveInstanceState() callback after the onPause() method, and before onStop(). Do not implement this callback in onPause().

Caution: You must always call the superclass implementation of onSaveInstanceState() so the default implementation can save the state of the view hierarchy.

To save additional state information for your activity, you must override onSaveInstanceState() and add key-value pairs to the Bundle object that is saved in the event that your activity is destroyed unexpectedly. For example:

static final String STATE_SCORE = "playerScore";
static final String STATE_LEVEL = "playerLevel";
...

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    // Save the user's current game state
    savedInstanceState.putInt(STATE_SCORE, mCurrentScore);
    savedInstanceState.putInt(STATE_LEVEL, mCurrentLevel);


    // Always call the superclass so it can save the view hierarchy state
    super.onSaveInstanceState(savedInstanceState);
}

More detail you can find here

Upvotes: 1

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