Java + Android Library : First Program

Create a Demo Project


Step - 1 : First create a 'JavaLibraryDemo '  project

Step - 2 : Creating a new Android Library
After creating the project, go to File -> New -> New Module:

Step - 3 :  Select Java Library.

Step - 4 : Next, you will be prompted to provide a name and the module name.
A. Enter Library Name - In my case 'mathlib-v1.0'
B. Package Name

Step - 5 : After finish, Project look like this in android studio

--------------------Configure----------------------

Step - 1 : Now, Configure the android project

File -> Project Structure -> app -> dependencies -> Click on (+) -> Module Dependency

Step - 2 : A 'Choose Module' popup will show, choose  module and press 'OK' -> 'OK'

--------------------Start Code </> -------------------------------

Here, We perform simple Add Operation

Step - 1 : Inside Library, goto Java 'Main' folder. RightClicl -> New -> Java Class ->

Name the class like - 'AdditionClass' -> finish

Write below code too -

Code -
----------

public class AdditionClass {

    public static Integer addValue(int n1, int n2){

        int sum = n1 + n2;
        return sum;
    }
}

------------

Step - 2 : Write this code in MainActivity

Code -

-------------------

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        performAddition(25, 35);

    }

    public void performAddition(int i, int j){

        int result = AdditionClass.addValue(i, j);
        System.out.println(result);

//        Optional, For more interactive
        new AlertDialog.Builder(MainActivity.this)
                .setMessage(String.valueOf(result))
                .show();

    }
}

public class MainActivity extends AppCompatActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        performAddition(25, 35);

    }

    public void performAddition(int i, int j){

        int result = AdditionClass.addValue(i, j);

        System.out.println(result);

//        Optional, For more interactive

        new AlertDialog.Builder(MainActivity.this)

                .setMessage(String.valueOf(result))

                .show();

    }

}

--------------------





Note : You can also use this tutorial for android library,  Only single change

- Choose 'Android Library' instead of 'Java library', when creating module.




22