title: Android set margins for control inside webview doesn't work
body: <p>I have a webview, a functionality that add a new button to this webview, the problem here is I can't not set the margins to this button and it always show on the top, left of webview.</p>
  
  <p>Or any solutions for my situation: I want to add a control at specify position(x, y) inside a webview, when users scroll on the webview, the control will be scroll as well and always be shown at exactly position I have set before?</p>
  
  <p>My xml layout:</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      tools:context=".MainActivity"
      android:id="@+id/mainLayout"
     &gt;
  
      &lt;WebView
          android:id="@+id/myWebView"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
  
          android:scrollbars="vertical"
          android:visibility="visible"&gt;
      &lt;/WebView&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>My code to create new button is:</p>
  
  <pre><code>private void createButton(WebView wv){
          //LinearLayout relativeLayout = (LinearLayout)findViewById(R.id.mainLayout);
          LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(60,60, Gravity.TOP);
          params.setMargins(50, 50, 0, 0);// Doesn't work at all here
  
          android.widget.Button button = new android.widget.Button(this);
          button.setText("Hello button");
  
          button.setLayoutParams(params);
  
          wv.addView(button);
      }
  </code></pre>
  
  <p>Any helps will be thanked in advanced</p>