Call a public method in the Activity class from another class?

Question

MAIN ACTIVITY

    public class MyActivity() extends Activity
    {
        onCreate()
        {
            MyClass myobj=new MyClass();    
        }
               


        

Answer 1

You have to pass instance of MainActivity into another class, then you can call everything public (in MainActivity) from everywhere.

MainActivity.java

public class MainActivity extends AppCompatActivity {

    // Instance of AnotherClass for future use
    private AnotherClass anotherClass;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // Create new instance of AnotherClass and
        // pass instance of MainActivity by "this"
        anotherClass = new AnotherClass(this);
    }

    // Method you want to call from another class
    public void myMethod(){
        ...
    }
}

AnotherClass.java

public class AnotherClass {

    // Main class instance
    private MainActivity mainActivity;  

    // Constructor
    public AnotherClass(MainActivity activity) {

        // Save instance of main class for future use
        mainActivity = activity;  

        // Call method in MainActivity
        mainActivity.myMethod();
    }
}