Full source code to build a simple dice roller app. We will display our dice as images in an ImageView. When we click on it, we generate a random number between 1 and 6 and then show the results by setting the appropiate dice image on our ImageView with the setImageResource method
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="tech.codingpoint.diceexample.MainActivity">
<ImageView
android:id="@+id/image_view_dice"
android:layout_width="300dp"
android:layout_height="300dp"
android:src="@drawable/dice1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
MainActivity.java
package tech.codingpoint.diceexample;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
private ImageView imageViewDice;
private Random rng = new Random();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageViewDice = findViewById(R.id.image_view_dice);
imageViewDice.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
rollDice();
}
});
}
private void rollDice() {
int randomNumber = rng.nextInt(6) + 1;
switch (randomNumber) {
case 1:
imageViewDice.setImageResource(R.drawable.dice1);
break;
case 2:
imageViewDice.setImageResource(R.drawable.dice2);
break;
case 3:
imageViewDice.setImageResource(R.drawable.dice3);
break;
case 4:
imageViewDice.setImageResource(R.drawable.dice4);
break;
case 5:
imageViewDice.setImageResource(R.drawable.dice5);
break;
case 6:
imageViewDice.setImageResource(R.drawable.dice6);
break;
}
}
}