- What is findViewById () method used for?
- What is the purpose of super onCreate () in Android Mcq?
- Is it possible activity without UI in Android?
- What is the use of savedInstanceState in Android?
- What is difference between immutable and final?
- What does onCreate method do in Android?
- What does super mean in Android?
- What is the difference between onCreate and onStart Android?
- How do I use onPause in Android?
- What is the purpose of super On create in Android?
- What is onSaveInstanceState?
- Is string immutable in Java?
- Can we override static method?
- Can a class be immutable in Android?
- What is the use of setContentView in Android?
What is findViewById () method used for?
Safe code using binding objects findViewById is the source of many user-facing bugs in Android.
It’s easy to pass an id that’s not in the current layout — producing null and a crash.
And, since it doesn’t have any type-safety built in it’s easy to ship code that calls findViewById(R..
What is the purpose of super onCreate () in Android Mcq?
Android class works in the same way. By extending the Activity class which have onCreate(Bundle bundle) method in which meaningful code is written and to execute that code in the defined activity, use the super keyword with the method onCreate() like super.
Is it possible activity without UI in Android?
The answer is yes it’s possible. Activities don’t have to have a UI. It’s mentioned in the documentation, e.g.: An activity is a single, focused thing that the user can do.
What is the use of savedInstanceState in Android?
The savedInstanceState is a reference to a Bundle object that is passed into the onCreate method of every Android Activity. Activities have the ability, under special circumstances, to restore themselves to a previous state using the data stored in this bundle.
What is difference between immutable and final?
final means that you can’t change the object’s reference to point to another reference or another object, but you can still mutate its state (using setter methods e.g). Whereas immutable means that the object’s actual value can’t be changed, but you can change its reference to another one.
What does onCreate method do in Android?
onCreate(Bundle) is where you initialize your activity. When Activity is started and application is not loaded, then both onCreate() methods will be called. But for subsequent starts of Activity , the onCreate() of application will not be called.
What does super mean in Android?
The super keyword refers to superclass (parent) objects. It is used to call superclass methods, and to access the superclass constructor. The most common use of the super keyword is to eliminate the confusion between superclasses and subclasses that have methods with the same name.
What is the difference between onCreate and onStart Android?
onCreate() is called when the when the activity is first created. onStart() is called when the activity is becoming visible to the user.
How do I use onPause in Android?
onPause(): This method gets called when the UI is partially visible to the user. If a dialog is opened on the activity then the activity goes to pause state and calls onPause() method. Here the activity is in the paused state. onStop(): This method gets called when the UI is not visible to the user.
What is the purpose of super On create in Android?
In android when you create an activity and you want to call the default behavior before your own logic or behavior then you use the “super” keyword. super relates not to a specific method, but to the whole parent class instead.
What is onSaveInstanceState?
onSaveInstanceState method gets called typically before/after onStop() is called. This varies from Android version to version. In the older versions it used to get before onStop() . Inside this method, we save the important values in the Bundle in the form of key value pairs.
Is string immutable in Java?
In Java, String is a final and immutable class, which makes it the most special. It cannot be inherited, and once created, we can not alter the object.
Can we override static method?
Can we Override static methods in java? We can declare static methods with same signature in subclass, but it is not considered overriding as there won’t be any run-time polymorphism. Hence the answer is ‘No’.
Can a class be immutable in Android?
Immutable classes cannot reassign values after it is instantiated. The constructor assign values to its private variables. … Avoid method overriding by making class final(Strong Immutability) or methods final(Week immutability). Clone deeply if it contain non primitive or mutable classes.
What is the use of setContentView in Android?
Actually setContentView() is a method part of android. app. Activity class. It helps to set our content or render our layout on the screen.