package com.example.myapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class A extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button button= (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent(A.this,B.class);
                startActivity(intent);
            }
        });
        setTXT();
    }
    private void setTXT(){
        Toast.makeText(getApplicationContext(),"Привет",Toast.LENGTH_SHORT).show();
    }
}






package com.example.myapp;

public class B extends A{
}