What s onCreate Bundle savedInstanceState

Question

Can anyone help me to know about the Bundle savedInstanceState in onCreate Bundle savedInstanceState  I am newbie in Android  I try to understand it from developer android com  But I am not able to understand  Can anyone simplify it

User · Accepted Answer

If you save the state of the application in a bundle (typically non-persistent, dynamic data in onSaveInstanceState), it can be passed back to onCreate if the activity needs to be recreated (e.g., orientation change) so that you don't lose this prior information. If no data was supplied, savedInstanceState is null.

... you should use the onPause() method to write any persistent data (such as user edits) to storage. In addition, the method onSaveInstanceState(Bundle) is called before placing the activity in such a background state, allowing you to save away any dynamic instance state in your activity into the given Bundle, to be later received in onCreate(Bundle) if the activity needs to be re-created. See the Process Lifecycle section for more information on how the lifecycle of a process is tied to the activities it is hosting. Note that it is important to save persistent data in onPause() instead of onSaveInstanceState(Bundle) because the latter is not part of the lifecycle callbacks, so will not be called in every situation as described in its documentation.

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User · Answer

onCreate Bundle savedInstanceState  gets called and savedInstanceState will be non-null if your Activity  and it was terminated in a scenario visual view  described above  Your app can then grab  catch  the data from savedInstanceState and regenerate your Activity

User · Answer

onCreate Bundle  is called when the activity first starts up  You can use it to perform one-time initialization such as creating the user interface  onCreate   takes one parameter that is either null or some state information previously saved by the onSaveInstanceState

User · Answer

onCreate Bundle savedInstanceState  Function in Android   When an Activity first call or launched then onCreate Bundle    savedInstanceState  method is responsible to create the activity   When ever orientation i e  from horizontal to vertical or vertical to    horizontal  of activity gets changed or when an Activity gets  forcefully terminated by any Operating System then savedInstanceState    i e  object of Bundle Class will save the state of an Activity   After    Orientation changed then onCreate Bundle savedInstanceState  will    call and recreate the activity and load all data from    savedInstanceState   Basically Bundle class is used to stored the data    of activity whenever above condition occur in app   onCreate   is not    required for apps  But the reason it is used in app is because that    method is the best place to put initialization code   You could also    put your initialization code in onStart   or onResume   and when you    app will load first  it will work same as in onCreate

User · Answer

As Dhruv Gairola answered  you can save the state of the application by using Bundle savedInstanceState  I am trying to give a very simple example that new learners like me can understand easily   Suppose  you have a simple fragment with a TextView and a Button  Each time you clicked the button the text changes  Now  change the orientation of you device emulator and notice that you lost the data  means the changed data after clicking you got  and fragment starts as the first time again  By using Bundle savedInstanceState we can get rid of this  If you take a look into the life cyle of the fragment Fragment Lifecylce you will get that a method  onSaveInstanceState  is called when the fragment is about to destroyed   So  we can save the state means the changed text value into that bundle like this   int counter    0    Override  public void onSaveInstanceState Bundle outState        super onSaveInstanceState outState       outState putInt  value  counter        After you make the orientation the  onCreate  method will be called right  so we can just do this   Override public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState        if savedInstanceState    null             it is the first time the fragment is being called         counter   0       else            not the first time so we will check SavedInstanceState bundle         counter   savedInstanceState getInt  value  0     here zero is the default value           Now  you won t lose your value after the orientation  The modified value always will be displayed

User · Answer

onCreate Bundle savedInstanceState  you will get the Bundle null when activity get starts first time and it will get in use when activity orientation get changed          http   www gitshah com 2011 03 how-to-handle-screen-orientation 28 html  Android provides another elegant way of achieving this   To achieve this  we have to override a method called onSaveInstanceState     Android platform allows the users to save any instance state   Instance state can be saved in the Bundle   Bundle is passed as argument to the onSaveInstanceState method   we can load the saved instance state from the Bundle passed as argument to the onCreate method  We can also load the saved instance state in onRestoreInstanceState method  But I will leave that for the readers to figure out

[android] What's onCreate(Bundle savedInstanceState)

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