How to remove Title Bar

To remove the Title bar for the single page or all page we set the code given bellow,

requestWindowFeture(Window.FEATURE_NO_TITLE);

and for all page you can set it on Androidmanifast file 

       android:theme="@android:style/Theme.NoTitleBar" >
                android:screenOrientation="portrait"
                  android:label="@string/app_name">