Introduction of three activity modules [onSavedInstanceState()] [onPause()] [onResume()]

迈不过友情╰ 2021-11-17 14:54 172阅读 0赞

`onSaveInstanceState()` is called by Android if the Activity is being stopped and **may be killed before it is resumed!** This means it should store any state necessary to re-initialize to the same condition when the Activity is restarted. It is the counterpart to the ```onCreate()` method, and in fact the `savedInstanceState` Bundle passed in to `onCreate()` is the same Bundle that you construct as `outState` in the `onSaveInstanceState()``` method.

`onPause()` and ```onResume()` are also complimentary methods. ```onPause()` is always called when the Activity ends, even if we instigated that (with a `finish()` call for example). We will use this to save the current note back to the database. Good practice is to release any resources that can be released during an `onPause()` as well, to take up less resources when in the passive state. `onResume()` will call our ```populateFields()` method to read the note out of the database again and populate the fields.

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populateField() function is used to assign values to EditText controls.you can see more details about it from reference link.

Reference: [http://code.google.com/android/intro/tutorial-ex3.html ][http_code.google.com_android_intro_tutorial-ex3.html]

转载于:https://www.cnblogs.com/EdgarSun/archive/2009/01/09/1372725.html

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[http_code.google.com_android_intro_tutorial-ex3.html]: http://code.google.com/android/intro/tutorial-ex3.html