Develop Reference

How to disable naviagation bar in Android LockScreen App like CM locker and OS8 lock screen

I tried setting systemUIView(View.GONE) and use Immersive Full-Screen Mode. But users can always get the naviagtion bar back by touching the bottom of the screen. The apps i mentioned above are able to hide it without root or setting default launcher.

Okay, I found a solution finally and here is how it's done:
Use SYSTEM_UI_FLAG_IMMERSIVE_STICKY to hide the navigation bar as follow, you may put the code inside onResume of your activity
View decorView = getWindow().getDecorView();
int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION |View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
decorView.setSystemUiVisibility(uiOptions);
Then, add a system error window using WindowManger and overlay it on top of everything
you can put this unescapable view anywhere you like, but if you want to do it while users locked the screen, add this flag:
getWindow().setFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED, WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
Et voilà

Well I've never achieved this but it seems that you will need to set some other flags to get this kind of view :
When you use the SYSTEM_UI_FLAG_IMMERSIVE flag, it hides the system bars based on what other UI flags you have set (SYSTEM_UI_FLAG_HIDE_NAVIGATION, SYSTEM_UI_FLAG_FULLSCREEN, or both). When the user swipes inward in a system bars region, the system bars reappear and remain visible.
Here is a snippet that you can use to set these flags :
// This snippet hides the system bars.
private void hideSystemUI() {
// Set the IMMERSIVE flag.
// Set the content to appear under the system bars so that the content
// doesn't resize when the system bars hide and show.
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);
}
// This snippet shows the system bars. It does this by removing all the flags
// except for the ones that make the content appear under the system bars.
private void showSystemUI() {
mDecorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
}
For more information go check Using Immersive Full-screen Mode from the android developer website.
Hope this help.

How can I create an app as full screen in all android devices and without additional tools like the Navigation bar in android

I use the android:Theme.Light.NoTitleBar.Fullscreen for setting the layout as the full screen and without a Title Bar. But now I have a problem. some android devices have the additional tools like the Navigation bar and when I run my app in the devices, because there are the additional tools like the Navigation bar in the android devices, as the result my app is not Full Screen really and I see the Navigation bar still. Are there a way to solve this problem? How Can I create my app as Full Screen in all version of the android (API 7 to higher) really?

You can force notification bar like this:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
}
But the Navigation Bar is not going to go... only on API lvl 19+ (4.4+) and it's called "Immersive mode". You can hide it and show it like this:
// This snippet hides the system bars.
private void hideSystemUI() {
// Set the IMMERSIVE flag.
// Set the content to appear under the system bars so that the content
// doesn't resize when the system bars hide and show.
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);
}
// This snippet shows the system bars. It does this by removing all the flags
// except for the ones that make the content appear under the system bars.
private void showSystemUI() {
mDecorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
}
For more info, check the official documentation: https://developer.android.com/training/system-ui/immersive.html

Hide Navigation Bar Permanently

I've followed this thread to hide Navigation bar:
Hide ICS back home task switcher buttons
Works fine when the Activity starts, but whenever I press anywhere on the screen the Navigation bar appears again. I've tried this on an empty Activity without any "views" except the Content View.
How can I hide it throughout the duration of my Activity without having to add some kind of Timer or a Thread to just hide it every millisecond?
It would be great to gain some extra screen size or be able to customize my own Navigation Bar throughout my App.
if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH )
getWindow().getDecorView().setSystemUiVisibility( View.SYSTEM_UI_FLAG_HIDE_NAVIGATION );
else if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB )
getWindow().getDecorView().setSystemUiVisibility( View.STATUS_BAR_HIDDEN );

This is a problem that came in a long time when we need to show som content in full screen, bumped the difficulty in being able to hide the status bar on some versions of Android:
Finally Google’s latest Android OS, KitKat, introduces a decent user-friendly tool that gives us ownership of that last bit of screen.
Using Immersive Full-Screen Mode see more in : https://developer.android.com/training/system-ui/immersive.html
// This snippet hides the system bars.
private void hideSystemUI() {
// Set the IMMERSIVE flag.
// Set the content to appear under the system bars so that the content
// doesn't resize when the system bars hide and show.
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);
}
// This snippet shows the system bars. It does this by removing all the flags
// except for the ones that make the content appear under the system bars.
private void showSystemUI() {
mDecorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
}
Here's how this has been a thorn in : http://blog.grio.com/2014/02/androids-hiding-of-the-system-bar-fixed.html

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.

How to hide the soft-key bar on Android phone?

　
When my app starts, I'd like to hide the soft keys bar (in red rectangle) to have a larger screen.
How can I hide it?
Do I need to show the bar purposely when the app quits? Or it will restore itself automatically after the app quits?
Android 4.1, with no hardware keys on phone front.

I know its late but it is the right answer so what you are trying to do is what called immersive mode. for (API 19)
check out: https://developer.android.com/training/system-ui/immersive.html
The code that you were asking for is:
#Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if (hasFocus) {
getWindow().getDecorView().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);
}
}

Try
getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
From official doc
The SYSTEM_UI_FLAG_LOW_PROFILE flag replaces the STATUS_BAR_HIDDEN
flag. When set, this flag enables “low profile" mode for the system
bar or navigation bar. Navigation buttons dim and other elements in
the system bar also hide. Enabling this is useful for creating more
immersive games without distraction for the system navigation buttons.
The SYSTEM_UI_FLAG_VISIBLE flag replaces the STATUS_BAR_VISIBLE flag
to request the system bar or navigation bar be visible.
The SYSTEM_UI_FLAG_HIDE_NAVIGATION is a new flag that requests the
navigation bar hide completely. Be aware that this works only for the
navigation bar used by some handsets (it does not hide the system
bar on tablets). The navigation bar returns to view as soon as the
system receives user input. As such, this mode is useful primarily for
video playback or other cases in which the whole screen is needed but
user input is not required.
The behavior of the nav bar is app dependent IIRC, so it should show again after the user leaves your app.