Intent GridLayout to 4 Activities

<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:columnCount="2">

    <Button
        android:id="@+id/button_activity2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Activity 2"
        android:onClick="openActivity2" />

    <Button
        android:id="@+id/button_activity3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Activity 3"
        android:onClick="openActivity3" />

    <Button
        android:id="@+id/button_activity4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Activity 4"
        android:onClick="openActivity4" />

</GridLayout>

public class Activity1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity1_layout);
    }

    public void openActivity2(View view) {
        Intent intent = new Intent(this, Activity2.class);
        startActivity(intent);
    }

    public void openActivity3(View view) {
        Intent intent = new Intent(this, Activity3.class);
        startActivity(intent);
    }

    public void openActivity4(View view) {
        Intent intent = new Intent(this, Activity4.class);
        startActivity(intent);
    }
}