If Your app is based on one orientation than mention that in manifest file with activity attributes
<activity android:name=".HandleDataActivity"
android:screenOrientation="portrait"> // or landscape
-
If Apps are working on both the orientations, one way is that you can make changes in Android Manifest file to maintain the data with activity attribute.
<activity android:name=".HandleDataActivity"android:configChanges="orientation|screenSize"> -
It can be done by coding using two methods which are used in activity life cycle when screen rotates
- onSaveInstanceState
- onRestoreInstanceState
This is the most common situation to save the basic data of your Activity or Fragment during orientation change. You can save Primitive data such as String, Boolean, Integers or Parcelable objects in a Bundle during the orientation change and read the same data when Activity recreated.
Saving and restoring the data works using two Activity lifecycle methods called onSaveInstanceState() and onRestoreInstanceState().
To save the state information override onSaveInstanceState() method and add key-value pairs to the Bundle object that is saved in the event that your activity is destroyed unexpectedly. This method gets called before onStop().
override fun onSaveInstanceState(outState: Bundle?)
{
`super.onSaveInstanceState(outState)`
`Toast.makeText(this,"onSaveInstanceState Method Called",Toast.LENGTH_LONG).show()`
`outState?.putString("name",""+etName?.text.toString()+" "+etMiddleName?.text.toString()+" "+etLastName?.text.toString())`
}
To recover your saved state from the Bundle override onRestoreInstanceState() method. This is called after onStart() and before onResume().
override fun onRestoreInstanceState(savedInstanceState: Bundle?)
{
`super.onRestoreInstanceState(savedInstanceState)`
`Toast.makeText(this,"onRestoreInstanceState Method Called",Toast.LENGTH_LONG).show()`
`setName(savedInstanceState?.getString("name","").toString())`
}
When AsyncTask is running without changing the screen orientation then it will start and finish its work normally. But problems begin to appear when the device orientation is changed while the AsyncTask is in the middle of the work.
The application will crash or java.lang.IllegalArgumentException i.e. View not attached to window manager will be thrown or Activity has leaked window.
To resolve this problem one option is to use IntentService along with BroadCastReceiver to deliver result.
Another option is to run the AsyncTask inside worker Fragment. As explained above using fragments is the cleanest way to handle configuration changes because Fragment has the ability to retain their instances simply by calling setRetainInstance(true) in one of its callback methods.