ACTIVITY RESTART ON ROTATION ANDROID

Samuel Fernandes

Total Post:159

Points:1117
Posted by  Samuel Fernandes
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In my Android application, when I rotate the device (slide out the keyboard) then my Activity is restarted (onCreate is called). Now, this is probably how it's supposed to be, but I do a lot of initial setting up in the onCreate method, so I need either:

Put all the initial setting up in another function so it's not all lost on device rotation or
Make it so onCreate is not called again and the layout just adjusts or
Limit the app to just portrait so that onCreate is not called.
  1. Mayank Tripathi

    Post:397

    Points:3117
    Re: Activity restart on rotation Android

    Depending on what you're doing in your initialization you could consider creating a new class that extends Application and moving your initialization code into an overridden onCreate method within that class.

    public class MyApplicationClass extends Application {
      @Override
      public void onCreate() {
        super.onCreate();
        // TODO Put your application initialization code here.
      }
    }
    The onCreate in the application class is only called when the entire application is created, so the Activity restarts on orientation or keyboard visibility changes won't trigger it.

    It's good practice to expose the instance of this class as a singleton and exposing the application variables you're initializing using getters and setters.

    NOTE: You'll need to specify the name of your new Application class in the manifest for it to be registered and used:

    <application
        android:name="com.you.yourapp.MyApplicationClass"
    Reacting to Configuration Changes

    As a further alternative, you can have your application listen for events that would cause a restart – like orientation and keyboard visibility changes – and handle them within your Activity.

    Start by adding the android:configChanges node to your Activity's manifest node

    android:configChanges="keyboardHidden|orientation"
    or for Android 3.2 (API level 13) and newer:

    android:configChanges="keyboardHidden|orientation|screenSize"
    Then within the Activity override the onConfigurationChanged method and call setContentView to force the GUI layout to be re-done in the new orientation.

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
      super.onConfigurationChanged(newConfig);
      setContentView(R.layout.myLayout);
    }

      Modified On May-19-2015 07:04:27 AM

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