Ndtyjky

This is a part of my activity class,

public class StatusActivity extends AppCompatActivity {





    private boolean cFlag = false;



    public boolean getFlag() { return cFlag;  }



    public void setFlag(boolean cFlag) {

        this.cFlag = cFlag;

    }



    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.list);

        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, 

                                      android.R.id.text1, messages);

        ListView listView = findViewById(android.R.id.list);

        listView.setAdapter(adapter);

        adapters.add(adapter);





        Button btn = findViewById(R.id.btnCustomerCheckIn);

        btn.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                setFlag(true);

                cFlag = getFlag();





                Intent intent = new Intent(StatusActivity.this, MainActivity.class);

                Toast.makeText(StatusActivity.this, "customer checked in", 

                                Toast.LENGTH_LONG).show();

                startActivity(intent);

            }

        });





    }

this is a part of another class named as position

public class Position {

    StatusActivity statusactivity = new StatusActivity();

    public  boolean ccflag = statusactivity.getFlag();

    statusactivity.setFlag(false);



    }

when i am calling

statusactivity.setFlag(false);

it is showing an error. couldn't recognize that what is the error that i am getting. but

statusactivity.getFlag(); 

is working properly. any help is appreciated

StatusActivity statusactivity = new StatusActivity();

This is totally wrong because you are trying to create a new Instance of activity.
If you want to use "setFlag" method from other activity then you must create a static method inside StatusActivity so you can access using directly StatusActivity.

And If you want to call from any fragment of this activity then please get an instance of this activity by the cast from "getActivity()" to StatusActivity and use that instance for call "setFlag" or "getFlag" method.

You can implement like below in Activity.

private static boolean cFlag = false;



    public static boolean getFlag() {

        return cFlag;

    }



    public static void setFlag(boolean cFlag) {

        StatusActivity.cFlag = cFlag;

    }

and call from position class like below

public class Position {

    public  boolean ccflag = StatusActivity.getFlag();

    StatusActivity.setFlag(false);

    }

you can not instantiate Activity class. if you want to call a method from activity, fist you should check that activity already running and not destroyed then by having the context of your class you just cast it like below then use its method

StatusActivity statusactivity= (StatusActivity )context;  

statusactivity.setFlag(false);