How to extend two library class in java class android

Question

I want to extend two library class files in a java class.How to do this.

You can't extend more than one inside a java class, What exactly you want to do, can you explain in more detail? — Swetank, Sep 30 '13 at 05:58
can you give more explanation on it. Which are the two classes that you want to extend in your class?Just paste those both classes prototype here. — Biraj Zalavadia, Sep 30 '13 at 05:58

score 0 · Accepted Answer · edited May 23 '17 at 12:29

You have not given more details about the question.

You can only extend a single class. And implement interfaces from many sources.

Extending multiple classes is not available.

You can use nested classes or inner classes

class A extends B {

 private class C extends D {

    // A , B , C , D accessible here 

  }
}

Why Use Nested Classes?

Compelling reasons for using nested classes include the following:

It is a way of logically grouping classes that are only used in one place: If a class is useful to only one other class, then it is logical to embed it in that class and keep the two together. Nesting such "helper classes" makes their package more streamlined.
It increases encapsulation: Consider two top-level classes, A and B, where B needs access to members of A that would otherwise be declared private. By hiding class B within class A, A's members can be declared private and B can access them. In addition, B itself can be hidden from the outside world.
It can lead to more readable and maintainable code: Nesting small classes within top-level classes places the code closer to where it is used.
when to use nested classes

You can find more solutions on this link

Edit

This is an answer to you comment. You want to call method of outer class in inner class. This is an example.

class Outer {
void show() {
    System.out.println("inside outter show");
}

class Inner{
    void show() {
        Outer.this.show();  //this is calling Outer class method into Inner class
        Example e = new Example(); //create object of another class
        e.show(); //call to method
        System.out.println("inside inner show");
    }
}

public static void main(String[] args) {
    Outer o = new Outer();
    Inner i = o.new Inner();  //create an object of Inner class
    i.show();   //this is calling Inner class method from outside method

 }
}

class Example
{
    void show()
    {
       System.out.println("inside example show");
    }
}

Output:

inside outter show
inside example show
inside inner show

I want to call a method in inner class from another class.How to call the method. — user, Sep 30 '13 at 07:10
Thank u..How to call the inner class using intent in android — user, Sep 30 '13 at 07:30

score 0 · Answer 2 · answered Sep 30 '13 at 06:06

Unfortunately in JAVA you can only extend a single class that means each Class can only extend one class. you can implement many interfaces but not extend.

however there are ways in which you can sort of surpass it, you can just make the libs public and then include them so you could create an instance and use their functions, you can create an inner class and use it for whatever purposes you need...

you can also create a chain of extension like:

public class A extends Activity

public class B extends A

so B will extend both...sort of

its hared to give you a working solution when we dont exactly know the issue,do you mean adding support libs? adding SDK? or really extending two classes (which is impossible straight forward).

@Aniket gave you an example of how to work around it so to speak...

hope I helped sorry for the bad news:)

How to extend two library class in java class android

2 Answers2