How to use onSavedInstanceState example please

The Bundle is a container for all the information you want to save. You use the put* functions to insert data into it. Here's a short list (there are more) of put functions you can use to store data in the Bundle.

putString
putBoolean
putByte
putChar
putFloat
putLong
putShort
putParcelable (used for objects but they must implement Parcelable)

In your onCreate function, this Bundle is handed back to the program. The best way to check if the application is being reloaded, or started for the first time is:

if (savedInstanceState != null) {
    // Then the application is being reloaded
}

To get the data back out, use the get* functions just like the put* functions. The data is stored as a name-value pair. This is like a hashmap. You provide a key and the value, then when you want the value back, you give the key and the function gets the value. Here's a short example.

@Override
public void onSaveInstanceState(Bundle outState) {
   outState.putString("message", "This is my message to be reloaded");
   super.onSaveInstanceState(outState);
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        String message = savedInstanceState.getString("message");
        Toast.makeText(this, message, Toast.LENGTH_LONG).show();
    }
}

Your saved message will be toasted to the screen. Hope this helps.

One major note that all new Android developers should know is that any information in Widgets (TextView, Buttons, etc.) will be persisted automatically by Android as long as you assign an ID to them. So that means most of the UI state is taken care of without issue. Only when you need to store other data does this become an issue.

From Android Docs:

The only work required by you is to provide a unique ID (with the android:id attribute) for each widget you want to save its state. If a widget does not have an ID, then it cannot save its state