call non static method from static method in android

Question

I tried to call non static method from static method but without any result ,my application works crash my code :

public class MainActivity extends Activity  {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        setAuth();
        ///

        ///



    }
    public static void setAuth() {

                new MainActivity().d();
        }
    public void d()
    {

        Toast.makeText(getApplicationContext(), "fff",Toast.LENGTH_SHORT).show();
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }



    }

Is it permissible to call non static method from static method in android?? and how???

First off all you can't do new MainActivity() for an Activity. I think your main task is to show Toast. So pass a Context object as param to setAuth() and show your toast using that context object. — Pankaj Kumar
– Pankaj Kumar, Commented Nov 20, 2013 at 7:10
You should consider spending a bit more time on simple Java programming before trying to make an Android app. — Snicolas
– Snicolas, Commented Nov 20, 2013 at 7:15
code isn't from my application, I tried simple code ,if the code work then change my application — user3001104
– user3001104, Commented Nov 20, 2013 at 7:21

Neil Townsend · Accepted Answer · 2013-11-20 07:36:28Z

2

A static method in a class must be able to be executed without any reference to an instantiation of the class:

class MyClass {
    int information;
    static int usefulNumber = 72;

    int method() {
        return information;
    }

    static int methodStatic() {
        // Cannot refer to information
        // But can refer to usefulNumber
    }
}

By definition therefore, it cannot execute a non-static method in the class because that method doesn't exist unless, as @RhinoFeeder says, you have instantiated the class and passed that instantiation to the static class:

    static int methodStatic2(MyClass myClass) {
        return myClass.method();
    }

edited Nov 20, 2013 at 7:36

answered Nov 20, 2013 at 7:17

Neil Townsend

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Comments

Alex · Accepted Answer · 2013-11-20 07:16:28Z

0

The only way to do this is if you have access to an instance of the class that contains the non-static method.

EDIT: I realized this answer sounds empty without a further explanation, since you do new-up a MainActivity.

new MainActivity().d();

Will not work in Android, as you cannot create a new Activity that way.

edited Nov 20, 2013 at 7:16

answered Nov 20, 2013 at 7:09

Alex

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1 Comment

Alex Over a year ago

Honestly, I would abandon this design all together. I would make setAuth take in a Context, and use that context to create the Toast in that method, axing d() all together. If you are set on the design you have now, @NeilTownsend provided a solid answer.

hasan · Accepted Answer · 2013-11-20 07:43:04Z

0

public static void setAuth(MainActivity activity) {
       activity.d();
}

That simple.

new MainActivity().d(); calls the method of another instance of the activity.

answered Nov 20, 2013 at 7:43

hasan

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1 Comment

hasan Over a year ago

Ok, try to call d() method from onCreate method and remove the call of the static method. to check if that's what is really causing the crash. because I don't believe it is.

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