Android Generate Random Color on Button Click Programmatically

In this tutorial we would going to change – set the background color of a View dynamically on button click. The random color would generate using JAVA’S default Random method. This is a pre inbuilt method available in JAVA. So here is the complete step by step tutorial for¬†Android Generate Random Color on Button Click Programmatically.

Contents in this project Generate Random Color on Button Click.

1. Create a Relative Layout view as Root view in your activity_main.xml file . This is the View which background color we would change on button click.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.android_examples.generaterandomcolor_android_examplescom.MainActivity"
    android:id="@+id/relativeLayout">

</RelativeLayout>

2. Create a button widget inside the root Relative layout view.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.android_examples.generaterandomcolor_android_examplescom.MainActivity"
    android:id="@+id/relativeLayout">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="Generate Random Color" />

</RelativeLayout>

3. Create Relative Layout and Button objects in MainActivity.java file.

Button button;
RelativeLayout relativeLayout;

4. Assign ID’S to them .

button = (Button)findViewById(R.id.button);

relativeLayout = (RelativeLayout)findViewById(R.id.relativeLayout);

5. Add onClickListener function on Button.

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {

        

    }
});

6. Create Random object and then create random color and set the color as background of View.

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {

        Random random = new Random();

        int color = Color.argb(255, random.nextInt(256), random.nextInt(256), random.nextInt(256));

        relativeLayout.setBackgroundColor(color);

    }
});

 Complete Source Code :

Code for MainActivity.java file.

package com.android_examples.generaterandomcolor_android_examplescom;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;

import java.util.Random;

public class MainActivity extends AppCompatActivity {

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

        button = (Button)findViewById(R.id.button);

        relativeLayout = (RelativeLayout)findViewById(R.id.relativeLayout);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Random random = new Random();

                int color = Color.argb(255, random.nextInt(256), random.nextInt(256), random.nextInt(256));

                relativeLayout.setBackgroundColor(color);

            }
        });
    }
}

Code for activity_main.xml layout file.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.android_examples.generaterandomcolor_android_examplescom.MainActivity"
    android:id="@+id/relativeLayout">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="Generate Random Color" />

</RelativeLayout>

Screenshots :

Generate Random Color

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