title: Set programmatically margin in android?
body: <p>I have bellow <code>xml</code> . In this <code>xml</code> i need that set <code>MarginTop "@+id/imgFooter" programatically</code> toward <code>"@+id/imgCenter"</code> .But i Can't .
  My <code>XML</code> :</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:id="@+id/rLayout"
      android:background="@drawable/backrepeat"&gt;
  
  
          &lt;ImageView
              android:id="@+id/imgHeader"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:contentDescription="One"
              android:layout_alignParentTop="true"
              android:adjustViewBounds="true"
              android:layout_centerHorizontal="true"
              android:src="@drawable/header" /&gt;
  
          &lt;ImageView
              android:id="@+id/imgCenter"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_below="@+id/imgHeader"
              android:layout_above="@+id/imgFooter"
              android:contentDescription="Two"
              android:src="@drawable/center" /&gt;
  
  
          &lt;ImageView
              android:id="@+id/imgFooter"
              android:contentDescription="Three"
              android:layout_alignParentBottom="true"
              android:adjustViewBounds="true"
              android:layout_centerHorizontal="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/footer" /&gt;
  
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>My <code>MainActivity.class</code> :</p>
  
  <pre><code>public class StartPage extends Activity{
      ImageView imgHeader;
      ImageView imgFooter;
      DisplayMetrics metrics;
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.start_page);
                  imgHeader = (ImageView) findViewById(R.id.imgHeader);
  
          metrics = new DisplayMetrics();
          getWindowManager().getDefaultDisplay().getMetrics(metrics);
  
          int width = metrics.widthPixels;
          int height = metrics.heightPixels;     
  
          int MPTopBottomHeader = (98 * width) / 1080;
          int MPLeftRightHeader = (110 * height) / 1920; 
  
  
          RelativeLayout.LayoutParams lpimgHeader = new RelativeLayout.LayoutParams(imgHeader.getLayoutParams());
          lpimgHeader.setMargins(MPLeftRightHeader, MPTopBottomHeader, MPLeftRightHeader, MPTopBottomHeader);
          imgHeader.setLayoutParams(lpimgHeader);
  
          imgFooter = (ImageView) findViewById(R.id.imgFooter);
  
          int MPTopBottomFooter = (185 * width) / 1080;
          int MPLeftRightFooter = (260 * height) / 1920; 
  
  ===== HERE ======&gt;RelativeLayout.LayoutParams lpimgFooter = new RelativeLayout.LayoutParams(imgFooter.getLayoutParams()); 
          lpimgFooter.setMargins(MPLeftRightFooter, MPTopBottomFooter, MPLeftRightFooter, MPTopBottomFooter);
          imgFooter.setLayoutParams(lpimgFooter);
      }
  }
  </code></pre>