How to set background color of an Activity to white programmatically?

Detailed Guide

Application in different Android versions

Android device fragmentation is legendary. To rug-proof your code against different Android versions and maintain backward compatibility, use this:

// ContextCompat : Our go-to guy when going back in Android versions.
getWindow().getDecorView().setBackgroundColor(ContextCompat.getColor(this, R.color.white));


Keep your color definitions neatly tucked away in colors.xml for future-proof readability:

<!-- No ambiguity here, only pure #FFFFFF -->
<color name="white">#FFFFFF</color>


Checking for Issues

Just as you wouldn’t expect a chameleon to maintain its color in different environments, your layout may act differently on varying screen sizes. Post-implementation checks to hunt down layout or rendering issues are paramount!

Added interactivity

If you're looking to give your user some "fun" by allowing them to change the background color at will, a SeekBar could just be your new best friend:

// SeekBar is on a mission. Be ready to be blinded or amazed, user choice! 
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        int colorValue = 255 - progress;
        // Interior design, Android style. Fifty shades of Grey, anyone?
        getWindow().getDecorView().setBackgroundColor(Color.rgb(colorValue, colorValue, colorValue));
    }
    // Insert drag queen jokes here for the onTouch events. 
});


Unified appearance through theming

For an app-wide style upgrade, consider implementing a custom theme. This not only lets your activities wear the same color but also screams, "Look! I've got styling skills!"

<!-- Instead of "White Christmas", we do "White Android". -->
<style name="AppTheme.WhiteBackground" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowBackground">@color/white</item>
</style>


Seamless responsiveness

To debug and ensure that this new white getup fits all devices and screen sizes, keep your layouts responsive. match_parent and ConstraintLayout are your secret weapons.

Post-implementation observations

Post-color implementation, do a thorough sweep for contrast and visibility. Your snow-white background might have turned your activity into Antarctica for some elements. It's retouch time!