[android] How do I keep the screen on in my App?

For my Android app I never want the phone to lock or the back light to turn off

You need to use Power Manager to acquire a wake lock in your application.

Most probably you are interested in a FULL_WAKE_LOCK:

PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK, "My Tag");
wl.acquire();
....
wl.release();

At this point method

final PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
        this.mWakeLock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag");
        this.mWakeLock.acquire();

is deprecated.

You should use getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); and getWindow().clearFlags(android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

No need to add permission and do tricks. Just use below text in your main layout.

  android:keepScreenOn="true"

Add one line of code after setContentView() in onCreate()

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_flag);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
}

getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

getWindow is a method defined for activities, and won't require you to find a View first.

There are multiple ways you can do it:

Solution 1:

class MainActivity extends AppCompactActivity {
    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);    
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    }
}

Solution 2:

In activity_main.xml file, simply add:

<android:KeepScreenOn="true"/>

My advice: please don't use WakeLock. If you use it, you have to define extra permission, and mostly this thing is useful in CPU's development environment.

Also, make sure to turn off the screen while closing the activity. You can do it in this way:

public void onDestry() {
    getWindow().clearFlags(android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
}

Adding android:keepScreenOn="true" in the XML of the activity(s) you want to keep the screen on is the best option. Add that line to the main layout of the activity(s).

Something like this

<LinearLayout 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"
    android:orientation="vertical"
    android:keepScreenOn="true">

...

</LinearLayout>

Lots of answers already exist here! I am answering this question with additional and reliable solutions:

Using PowerManager.WakeLock is not so reliable a solution, as the app requires additional permissions.

<uses-permission android:name="android.permission.WAKE_LOCK" />

Also, if it accidentally remains holding the wake lock, it can leave the screen on.

So, I recommend not using the PowerManager.WakeLock solution. Instead of this, use any of the following solutions:

First:

We can use getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); in onCreate()

@Override
        protected void onCreate(Bundle icicle) {
            super.onCreate(icicle);    
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        }

Second:

we can use keepScreenOn

1. implementation using setKeepScreenOn() in java code:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        View v = getLayoutInflater().inflate(R.layout.driver_home, null);// or any View (incase generated programmatically ) 
        v.setKeepScreenOn(true);
        setContentView(v);
       }

Docs http://developer.android.com/reference/android/view/View.html#setKeepScreenOn(boolean)

2. Adding keepScreenOn to xml layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:keepScreenOn="true" >

Docs http://developer.android.com/reference/android/view/View.html#attr_android%3akeepScreenOn

Notes (some useful points):

1. It doesn't matter that keepScreenOn should be used on a Main/Root/Parent View. It can be used with any child view and will work the same way it works in a parent view.
2. The only thing that matters is that the view's visibility must be visible. Otherwise, it will not work!

You can simply use setKeepScreenOn() from the View class.

Don't Use Wake Lock.

It requires permission and other stuff and may cause error if you forget to set it in right time.

The easiest way is to use the below code when you want to keep your screen on..

 getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

One addition to the answer if you want to remove or terminate keep_Screen_on

getWindow().clearFlags(android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

you can also see here..

And the best and easiest way .. Using android:keepScreenOn="true" in layout root of your activity does the same thing without extra code. But it will remain it in Keep_Scree_on State..

It can be vary on your demand See here