Develop Reference

Navigation back button on Android is not working

I have wrote this code to enable the navigation back button. Its appearing on run time but after clicking on it is not doing anything. Can someone tell me please what I'm missing?
// Get a support ActionBar corresponding to this toolbar
ActionBar ab = getSupportActionBar();
// Enable the Up button
ab.setDisplayHomeAsUpEnabled(true);
Thank you!

You should override onOptionsItemSelected method in your activity.
override fun onOptionsItemSelected(item: MenuItem): Boolean {
return when (item.itemId) {
android.R.id.home -> {
finish()
true
}
else -> super.onOptionsItemSelected(item)
}
}
Also if i'm not mistaken you should add this to your action bar to:
supportActionBar?.setDisplayShowHomeEnabled(true)

How to block navigation bar/status bar android java

How to block the navigation bar in android from my app. My app must haven't take the chance go to the settings and other components.
This code on Kotlin
I block the action bar by: window.addFlags(WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY) window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN)
In the photo it is the red zone, I can to override back-button and home-button (I make my app as a launcher for android) and I have did this.
But the main problem - is the button of multitasking - green zone.
The overriding method onUserLeaveHint not solve my problem.
How to remove this button or hide the navigation bar?

I have used below code for hiding the navigation bar & status bar in activity.
#Override
public void onWindowFocusChanged(boolean hasFocus)
{
super.onWindowFocusChanged(hasFocus);
View view = getWindow().getDecorView();
if (hasFocus) {
view.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOU _STABLE
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
|
View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
);
}
}
In one of My Custom camera app i have used this which shows the full screen camera view witout notification bar & status bar and when you drag from top or bottom then it will show you.
Happy Coding... :)

Please refer this example.
in which shown how to disable :
[Click here][below]
https://github.com/mugku/Android-LockScreenSample-DisableHomeButtonKey
Its tricky part pelase have h deep dive into this.or please check other lock screen example or locker apps. in which screen lock screen has this code.

#Override
protected void onPause() {
super.onPause();
if(SettingsProvider.loadPreventOverviewButtonMode(this)) {
ActivityManager activityManager = (ActivityManager) getApplicationContext()
.getSystemService(Context.ACTIVITY_SERVICE);
activityManager.moveTaskToFront(getTaskId(), 0);
}
}

Window type can not be changed after the window is added

I'm trying to make custom lock screen. So, there I need not to allow user to press Home Button. In the beginning I write
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.lock_screen);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
|WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
Then I override OnKeyDown
#Override
public boolean onKeyDown(int keyCode, android.view.KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_VOLUME_DOWN)||(keyCode == KeyEvent.KEYCODE_POWER)||(keyCode == KeyEvent.KEYCODE_VOLUME_UP)||(keyCode == KeyEvent.KEYCODE_CAMERA)) {
//this is where I can do my stuff
return true; //because I handled the event
}
if((keyCode == KeyEvent.KEYCODE_HOME)){
return true;
}
return false;
}
Here I override onAttacheToWindow
#Override
public void onAttachedToWindow() {
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
super.onAttachedToWindow();
}
But it's giving me error IllegalArgumentException: Window type can not be changed after the window is added. Where is my mistake?
How can I handle Home Button?

There is no "good" way to handle the home button to "do nothing". You really only have two options which may or may not be good enough for you:
Create your own home launcher. Users must select your app as their home launcher.
You could also create a Service where you add a view to your window and it gets plastered on top of everything else. See my previous answer here with "displaying" a webview in a Service: Android: Using WebView outside an Activity context. You will need to modify params to fill the screen and also fix WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE to use the right flags to allow clicks. This won't actually block the home button but it will basically disable it's functionality. Lastly, this might not work on Android 5.0+ as the Status bar's dropdown may overlay your window.

Stop the sliding screen at the middle

HomeActivity.java
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
Button btnopen = (Button)findViewById(R.id.btnWindowAnimation);
btnopen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent slideactivity = new Intent(HomeActivity.this, CartActivity.class);
Bundle bndlanimation =
ActivityOptions.makeCustomAnimation(getApplicationContext(), R.anim.animation,R.anim.animation2).toBundle();
startActivity(slideactivity, bndlanimation);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.layout.home, menu);
return true;
}
HomeActivity has a button and it will help to slide the 1st screen and bring the second screen.
animation.xml
android:fromXDelta="100%p"
android:toXDelta="25%p"
android:duration="5000"
This animation code is helping me to slide my screen after pressing the button. As shown in this video
https://www.youtube.com/watch?v=EzgGGWpRES0
I want to stop the new screen at the middle without covering the 1st screen completely.
Any suggestions? I have used another activity called cart( i haven't used fragments here)

Sounds like you want a NavigationDrawer.
You can find out more information on the Android developer site:
https://developer.android.com/design/patterns/navigation-drawer.html
https://developer.android.com/training/implementing-navigation/nav-drawer.htmlA

Your Requirement is to partially Display an Overlapping Activity on an Existing Activity. This is Possible with Sliding Menu Library (Which does not mean to technically create a floating Activity, but to create a Floating View integrated within the Sliding Menu that will be displayed partially on top on an Activity).
In case, if you are regarding this as some sort of Default Menu then please take a look at this Image
If this is your actual Requirement, then here are the details for you.
Sliding Menu Library is an OpenSource Library, you can use it for displaying a partially visible Sliding Menu on top of an Activity.
Here is the link of Sliding Menu Lib :
https://github.com/jfeinstein10/SlidingMenu
You can navigate to the example directory present in this Project for the demonstration of it's Usage.
I hope thie helps :)

Hiding title bar / notification bar when device is oriented to landscape

I want my title bar to be hidden when I turn my device to landscape. I have seen the XML option to hide the title bar, and the following example of doing it programmatically:
//Remove title bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
//Remove notification bar
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
BUT, I am using configChanges parameter for orientation and screenSize, so my activity is not re-created again when it is orienting to landscape (I'm doing this for some reasons). So I cannot use the above methods as these calls need to be made before setContentView().
So any ideas? Thank you.

was searching for an answer, ended up here, put the pieces together and here they are:
if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
}
else {
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
}

Assuming you have defined configChangesfor the Activity in the manifest then you can achieve your issue overriding onConfigurationChanged method:
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
if(newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
getActionBar().hide();
} else {
getActionBar().show();
}
}
You will have to use getSupportActionBar() instead of getActionBar() if using the support library.

first check your device orientation by using following code
The current configuration, as used to determine which resources to retrieve etc, as available from the Resources' Configuration object as:
getResources().getConfiguration().orientation
Then do the necessary coding related to hide title bar and notification bar.

#Override
public void onConfigurationChanged(Configuration config) {
super.onConfigurationChanged(config);
if(config.orientation == Configuration.ORIENTATION_LANDSCAPE) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
getActionBar().hide();
} else {
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
getActionBar().show();
}
}
You can use this I have tried by my self.

In your "AndroidManifest.xml", in the activity tag you can specify "NoTitleBar" in the theme property so that it will always hide the title:
<activity
android:name="com.my_package.MyActivity"
android:theme="#android:style/Theme.NoTitleBar.Fullscreen"
android:configChanges="navigation|orientation|screenLayout|layoutDirection">