in styles.xml add your custom style:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="AppBaseTheme" parent="@android:style/Theme.Light.NoTitleBar.Fullscreen">
    </style>
</resources>

Create your custom layout for the dialog: fullscreen.xml:

<RelativeLayout xmlns:android="<http://schemas.android.com/apk/res/android>"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    
</RelativeLayout>

Then in java file you can use it for an Activity or Dialog etc:

import android.app.Activity;
import android.app.Dialog;
import android.os.Bundle;

public class FullscreenActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //You can set no content for the activity.
        Dialog mDialog = new Dialog(this, R.style.AppBaseTheme);
        mDialog.setContentView(R.layout.fullscreen);
        mDialog.show();
    }
}