Develop Reference

How to make a lock screen which prevents home, back, or overView press?

My intention is to make a Lock screen Application.
I already tried all available answers. If someone who did implement this kind of app, can help me then all the better.
In other lock screen Application home,back,overView press working but they not showing it. they are only persistently showing there there lock screen.
they are asking permission for Draw over other app for it.

You can hide navigation bar like this:
View decorView = getWindow().getDecorView();
decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

How to hide softkeys in fullscreen mode for Samsung device in Android app

My app has an option to go into fullscreen mode. Users of device Samsung Galaxy S7 Edge report to me that the navigation soft buttons are displayed in this case and do never vanish when the app is in fullscreen.
Here is the code I am using:
getWindow().addFlags(
WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
mainFrame.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LOW_PROFILE |
View.SYSTEM_UI_FLAG_FULLSCREEN |
View.SYSTEM_UI_FLAG_LAYOUT_STABLE |
View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY |
View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION |
View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
);
I have already played around with some of the options but it is hard because I do not own a Samsung device. Can someone with this device tell me the correct settings so navigation soft keys are not displayed in fullscreen mode?

i found something that might be helpfull. It's from Google's Developers site and I think it does exactly what you are looking for. I hope it will be some kind of help.
I think this part in the beginning is what you need but I also provide you a link below for more information:
Android 4.4 (API Level 19) introduces a new SYSTEM_UI_FLAG_IMMERSIVE flag for setSystemUiVisibility() that lets your app go truly "full screen." This flag, when combined with the SYSTEM_UI_FLAG_HIDE_NAVIGATION and SYSTEM_UI_FLAG_FULLSCREEN flags, hides the navigation and status bars and lets your app capture all touch events on the screen.
https://developer.android.com/training/system-ui/immersive.html
EDIT
i found an answer to a similar question with yours and the suggested approach is the following. try adding this to your code. it will do the trick.
int UI_OPTIONS = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION |
View.SYSTEM_UI_FLAG_FULLSCREEN |
View.SYSTEM_UI_FLAG_LAYOUT_STABLE |
View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY |
View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION;
getWindow().getDecorView().setSystemUiVisibility(UI_OPTIONS);
Here is the link to the original: https://stackoverflow.com/a/31483291/8434076

Strange behavior of fullscreen mode on Android 7.0

I have an application which will show fullscreen without problem on Android 4-6. But once test on Android 7.0, although the navigation and status bar are hide, the navigation bar position seems still occupied by a white bar. My application cannot automatically resize to occupy that space.
mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
I use the above code to do the fullscreen. Please advise. Thanks.

Permanently hide bottom bar

I am working on custom screen lock app where we need to full screen view hiding the top and bottom bars completely. The app is for Android phones only and not tablets. I achieved this partially by using Immersive mode but the issue is the bottom bar & top appears for few seconds on touching bottom or top of the screen.
Below is the code in my activity to do this :
final int flags = View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
getWindow().getDecorView().setSystemUiVisibility(flags);
I have tried various options but unable to hide the bars permanently. Please advise.

How do I remove the navigation bar from my Android build?

Since the device I am developing has physical buttons, I do not want to see a navigation bar taking up my screen space. Rowboat-android on Beagleboneblack shows the navigation bar by default. Where do I turn it off?
EDIT: I am not developing applications. I am developing a Beaglebone based device. I want to remove the bar globally from the system. Somewhere there should be a code or setting in the Android source.

Found the answer at Building a wireless Android device using BeagleBone Black
Basically I edited device/ti/beagleboneblack/overlay/frameworks/base/core/res/res/values/config.xml file to set this entry:
<bool name="config_showNavigationBar">false</bool>

You should use IMMERSIVE flag like this:
private void hideSystemUI() {
mDecorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
| View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
| View.SYSTEM_UI_FLAG_IMMERSIVE);
}
For more info, I recommend you to take a look at here.