Table of Contents
Why it is recommended to use default constructor to create a fragment?
TL;DR A class used to control the instantiation of Fragment instances. Traditionally, a Fragment instance could only be instantiated using its default empty constructor. This is because the system would need to reinitialize it under certain circumstances like configuration changes and the app’s process recreation.
Why do we need default constructors?
Compiler defined default constructor is required to do certain initialization of class internals. It will not touch the data members or plain old data types (aggregates like an array, structures, etc…). However, the compiler generates code for default constructor based on the situation.
Why do we need a default constructor in JPA?
The JPA specification requires that all persistent classes have a no-arg constructor. This constructor may be public or protected. Because the compiler automatically creates a default no-arg constructor when no other constructor is defined, only classes that define constructors must also include a no-arg constructor.
What does a default constructor do?
In both Java and C#, a “default constructor” refers to a nullary constructor that is automatically generated by the compiler if no constructors have been defined for the class. The default constructor implicitly calls the superclass’s nullary constructor, then executes an empty body.
Why do we need default constructor in fragment?
If the constructor is explicit, as in the unaltered example, then it’s really there to ensure the no-args constructor works if other constructors are added, and the comment serves as a reminder (that or the original author didn’t really understand the purpose and/or how the language works).
How can two fragments communicate?
Fragment Communication
- Make an Interface in your FragmentA.
- Implement the Interface of the FragmentA in your Activity.
- Call the Interface method from your Activity.
- In your Activity, call your FragmentB to do the required changes.
Should you always have a default constructor?
If you don’t want someone to be able to initialize the class without providing data you should create a default constructor which is private to be explicit about the fact that you are preventing instances from being constructed with no input data.
Should all classes have a default constructor?
If your class is able to provide sane defaults for all fields that comprise a valid state for objects of that class, then a default constructor is most likely a good idea. Also, some libraries require the existence of a default constructor for certain operations.
Why is it important to provide a default constructor in Java What happens if your class doesn’t have a no argument constructor?
The arguments of a constructor can only be found by type, not by name, so there is no way for the framework to reliably match properties to constructor args. Therefore, they require a no-arg constructor to create the object, then can use the setter methods to initialise the data.
Why do we need a default constructor in spring boot?
1 Answer. The reason is that spring uses CGLIB to proxy @Configuration classes and there is limitation in Spring, that classes proxied with CGLIB prior to version 4 are required to have default no-args constructor. Prior to Spring 4, CGLIB-based proxy classes require a default constructor.
How many arguments does a default constructor have?
1. Default Constructors: Default constructor is the constructor which doesn’t take any argument. It has no parameters.
Why a fragment should not communicate with another fragment directly?
Two Fragments should never communicate directly. The reason for this is that Fragment s are fluid & dynamic UI components that may fade in and out of view. Only the hosting Activity is capable of determining if a Fragment is added to the UI or has been detached from it.
https://www.youtube.com/watch?v=9EdvcycKP9A