Q 9 – Is it mandatory to call onCreate() and onStart() in android? It is not mandatory, the program will work perfectly without fail, but the programmer has to implement the life cycle of activity.
What is the purpose of onCreate () function *?
onCreate(Bundle savedInstanceState) Function in Android:
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.
Is onCreate a callback?
You must implement this callback, which fires when the system first creates the activity. On activity creation, the activity enters the Created state. In the onCreate() method, you perform basic application startup logic that should happen only once for the entire life of the activity.
Is onCreate only called once?
@OnCreate is only for initial creation, and thus should only be called once. If you have any processing you wish to complete multiple times you should put it elsewhere, perhaps in the @OnResume method.
What is off line synchronization in android?
Synchronizing data between an Android device and web servers can make your application significantly more useful and compelling for your users. For example, transferring data to a web server makes a useful backup, and transferring data from a server makes it available to the user even when the device is offline.
What is onCreate () method?
onCreate is used to start an activity. super is used to call the parent class constructor. setContentView is used to set the xml.
Why is onCreate protected?
onCreate is not private because you do want to subclass an Activity and then use the super Activity onCreate method for the subclass. Actually every Activity you design extends android. app. Activity, so if onCreate was private in that super class, then you wouldn’t be able to call onCreate at all.
Which callback is called when the activity is no longer visible?
Explanation: onStop() : This callback is called when the activity is no longer visible.
How does the onCreate () callback work?
This callback is fired when the system first creates the activity. In onCreate method, all such operations are performed which should be done only once for the entire life of the activity. This method has a parameter savedInstanceState which is a bundle object. It contains activity’s previous saved state.
Is onDestroy always called?
Android Activity onDestroy() is not always called and if called only part of the code is executed. onDestroy() is not always called. If called, only part of the code is executed.
What is the difference between onCreate () and onStart ()?
onCreate() is called when the when the activity is first created. onStart() is called when the activity is becoming visible to the user.