android - Remove white gabs, actionbar and add my custom logo -

i want remove uglyness , fix basic isues have. want actionbar removed ugly white gabs gone , custom logo on app icon in phone if 1 know how let me know. add printscreen link printscreen app made in bluestacks

those things should fixed:

1. actionbar gone
2. open page in app must work without opening browser
3. white gabs (left, right, bottom , top gone)
4. add custom logo app icon on fhone

main_activity.xml

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" android:paddingbottom="@dimen/activity_vertical_margin" tools:context=".mainactivity">   <webview     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:id="@+id/webview"     android:layout_alignparenttop="true"     android:layout_alignparentleft="true"     android:layout_alignparentstart="true"     android:layout_alignparentbottom="true"     android:layout_alignparentright="true"     android:layout_alignparentend="true" /> 

mainactivityjava.java

    package nl.brasseriekakelbont.httpwww.zorghoevekakelbontapp;  import android.support.v7.app.actionbaractivity; import android.os.bundle; import android.view.menu; import android.view.menuitem; import android.webkit.webview;   public class mainactivity extends actionbaractivity {      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          string url="http://www.zorghoevekakelbont.nl/";         webview view=(webview) this.findviewbyid(r.id.webview);         view.getsettings().setjavascriptenabled(true);         view.loadurl(url);     }      @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.menu_main, menu);         return true;     }      @override     public boolean onoptionsitemselected(menuitem item) {         // handle action bar item clicks here. action bar         // automatically handle clicks on home/up button, long         // specify parent activity in androidmanifest.xml.         int id = item.getitemid();          //noinspection simplifiableifstatement         if (id == r.id.action_settings) {             return true;         }          return super.onoptionsitemselected(item);     } } 

androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="nl.brasseriekakelbont.httpwww.zorghoevekakelbontapp" >     <uses-permission android:name="android.permission.internet"/>     <application         android:allowbackup="true"         android:icon="@mipmap/ic_launcher"         android:label="@string/app_name"         android:theme="@style/apptheme" >         <activity             android:name=".mainactivity"             android:label="@string/app_name" >             <intent-filter>                 <action android:name="android.intent.action.main" />                  <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>     </application> </manifest> 

if need more info add fast possible , me.