public class MainActivity extends Activity

{

int counter;

Button add, sub;

TextView display;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

counter = 0;

add = (Button) findViewById(R.id.bAddOne);

sub = (Button) findViewById(R.id.bSubOne);

display = (TextView) findViewById(R.id.tvDisplay);

add.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

counter++;

display.setText("Your total is " + counter);

}

});

sub.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

counter--;

display.setText("Your total is " + counter);

}

});

}

}