How to place small image on centre of webview background

Am trying to place a small image on the centre of my WebView so when webview doesn't load any content the image will be visible. The problem is that the image take the full width and height of the webview, I have tried many things to place it on the centre but none of it worked. And my last attempt doesn't allow the app to lunch.

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:background="@color/colorPrimary"
        tools:context=".MainActivity"
        android:id="@+id/activity_main">
    <WebView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorPrimary"
        android:layout_gravity="center"
        android:id="@+id/AppId">
    </WebView>
</RelativeLayout>

MainActivity.java

    webview.setBackgroundResource(R.drawable.wbg_icon);
    webview.setBackgroundColor(0x00000000);

    RelativeLayout relativeLayout = new RelativeLayout(MainActivity.this);
    RelativeLayout.LayoutParams layoutParams= new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, RelativeLayout.LayoutParams.FILL_PARENT);
    layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT, 1);
    relativeLayout.addView(webview, layoutParams);

<FrameLayout 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:background="@color/colorPrimary"
    tools:context=".MainActivity"
    android:id="@+id/activity_main">
    <WebView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorPrimary"
        android:layout_gravity="center"
        android:id="@+id/AppId">
    </WebView>
    <ImageView
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:src="@drawable/ic_launcher"/>
</FrameLayout>