title: How to modify marginTop by code?
body: <p>I'm trying to find a way to modify marginTop for an EditText by code...I read about setLayoutParams but I get ForceClose and this message :</p>
  
  <pre><code>08-05 14:53:59.715: ERROR/AndroidRuntime(913): java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams
  08-05 14:53:59.715: ERROR/AndroidRuntime(913):     at android.widget.RelativeLayout$DependencyGraph.findRoots(RelativeLayout.java:1291)
  08-05 14:53:59.715: ERROR/AndroidRuntime(913):     at android.widget.RelativeLayout$DependencyGraph.getSortedViews(RelativeLayout.java:1238)
  08-05 14:53:59.715: ERROR/AndroidRuntime(913):     at android.widget.RelativeLayout.sortChildren(RelativeLayout.java:279)
  08-05 14:53:59.715: ERROR/AndroidRuntime(913):     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:299)
  08-05 14:53:59.715: ERROR/AndroidRuntime(913):     at android.view.View.measure(View.java:7964)
  </code></pre>
  
  <p>Can anyone explain what should I do?</p>
  
  <pre><code>giveuser = (EditText) findViewById(R.id.txt_username);
  LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
          lp.setMargins(5,5,5,5);
          giveuser.setLayoutParams(lp);
  </code></pre>
  
  <p>and in xml :</p>
  
  <pre><code>&lt;EditText android:id="@+id/txt_username"
          android:layout_height="wrap_content" android:layout_width="350px"
          android:layout_centerHorizontal="true" android:layout_below="@+id/loginsubtitle"
          android:layout_marginTop="180dip" android:singleLine="true"
          android:hint="Identifiant" /&gt;
  </code></pre>