Put this one line before setContentView
requestWindowFeature(Window.FEATURE_NO_TITLE);
//setContentView(R.layout.main_activity);
And if you want full screen then use below code:
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
//setContentView(R.layout.main_activity);
Yeah, This one also. Just put theme
on AndroidManifest.xml
<activity
android:name="MainActivity"
android:label="@string/app_name"
android:screenOrientation="portrait"
android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen"/>