Calling other App from one App

package com.example.testintaller;

import android.app.Activity;

import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    private Button btn;

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

        btn = (Button) findViewById(R.id.button1);

        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

               

                   
                     Intent intent = new Intent(Intent.ACTION_MAIN);
                     intent.setClassName("package", "package.classname");
                     intent.putExtra("name", "xxx");
                     intent.putExtra("password", "yyyy");
                    startActivity(intent);
                   
           

            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}


Note : Activity class of ther App which you are calling should be exported i,e in manifest we should give as android:exported = "true"