Android: Enforcing a wakelock is sometimes necessary but should be used with caution as it will take it's toll on the battery.

Android

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.PowerManager;

public class DoNotDimScreen extends Activity  {
	
	private PowerManager.WakeLock wl;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
		wl = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK, "DoNotDimScreen");
	}
		
	@Override
	protected void onPause() {
		super.onPause();
		wl.release();
	}

	@Override
	protected void onResume() {
		super.onResume();
		wl.acquire();
	}
}

You will need to include this permission in your manifest:
<uses-permission android:name="android.permission.WAKE_LOCK" />