Develop Reference

Android how to hide status bar without ActionBar

is it possible to hide status bar:
And show action bar without it?

try this..
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);

Another way .In your manifest xml, at application level set this:
<activity
android:theme="#android:style/Theme.NoTitleBar.Fullscreen" />
I hope it will works

Another way of hiding title bar

I am using this code for hiding the title bar. Is there any other way of doing the same?
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(
WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);

You can modify your manifest to use a theme that doesn't use a titlebar
<activity android:name=".MainActivity"
android:label="#string/app_name"
android:theme="#android:style/Theme.Black.NoTitleBar.Fullscreen">
or you can specify a new style as done in this answer:

For Api level 14 and above you can use
getActionBar().hide();
else for below api if you have to add v7 support library change Activity to ActionBarActivity
then you can just call
getSupportActionBar().hide();
This will give you full screen with notification bar

Hide the status bar,but my view does not go to the top

I use
mContext.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
mContext.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
mContext.getWindow().getDecorView().requestLayout();
to hide the status bar after setContentView.
The status bar is hided,but my view does not go to the top.There is a black rectangle
instead of the status bar.

You can use this in the Manifest file of that particular activity. remove above code from java file and put below code in Manifest in the activity
android:theme="#android:style/Theme.Black.NoTitleBar.Fullscreen"

here is the solution : just check it out
// hide titlebar of application
// must be before setting the layout
requestWindowFeature(Window.FEATURE_NO_TITLE);
// hide statusbar of Android
// could also be done later
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);

For hiding the status bar please add request feture with no title and flag as full screen then
add the content view.
Code is
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_test);
And for only the notification bar
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

How to add TitleBar in this android example?

I am new to implement the ListView with section.
I have use this application to implement the section to my list view.
Now I want to add the Titlebar that display the application page title. Then where do I have to make a change? In the xml file or in the Java file?
Please refer the example and let me tell what should I have to change to make Titlebar for my app.

Try this...
final Activity activity = this;
activity.setTitle("Settings");
if you disabled the title bar using, this.requestWindowFeature(Window.FEATURE_NO_TITLE);
remove it.
(OR)
Try this..
final Activity activity = this;
this.requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
setContentView(R.layout.settings);
activity.setTitle("Settings");

There are two ways to change title bar for your activity:
Design time (that is, change title in AndroidManifest.xml file).
By coding (that is, you can code to change the activity title).
Example for 1st:
you can Change the Title of each screen (i.e. Activity) by setting their Android:label inside the AndroidManifest.xml file:
<activity android:name=".Hello_World"
android:label="This is the Hello World Application">
</activity>
And yes, to display customized title bar for your activity, go through this answer: How to change the text on the action bar

In your AndroidManifest.xml file you have a section for each activity that looks like this
<activity
android:label="Your Activity"
android:name=".YourActivity" />
where the android:label tag defines what the text in the titlebar is.

Android: How to set icon in title bar of Dialog activity?

I declared a dialog activity in my Manifest as follows:
<activity android:name=".myDialog"
android:label="#string/title_dlg"
android:icon="#android:drawable/ic_dialog_alert"
android:exported="false"
android:excludeFromRecents="true"
android:theme="#android:style/Theme.Dialog">
However, only the title's text appears in the title bar and the icon appears to be ignored.
Is there a way to also show the icon in the title bar?

Use this after your super.onCreate(savedInstanceState); call:
requestWindowFeature(Window.FEATURE_LEFT_ICON);
Then, set your contentView(R.layout.youLayout);
and then use this:
getWindow().setFeatureDrawableResource(Window.FEATURE_LEFT_ICON, android.R.drawable.ic_dialog_alert);
The order is important.

I think using below line after super call will work
requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
Keep in mind to place it before setting content view