changing place of button using layout function in absolute layout

I am trying to position a button in a different place using absolute layout. I am using the following xml file:

<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:orientation="vertical"
  android:background="@drawable/bcgrd">
  <Button
    android:id="@+id/start_challenge"
    android:textStyle="bold"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text = "Start Challenge"
    android:textColor= "@color/light_gray"
    android:background="@color/background">
    </Button>  
</AbsoluteLayout>

the java file contains the following code:

    Button start_it = (Button)findViewById(R.id.start_challenge);
    start_it.layout(200, 200, 200, 200);

but nothing happen (the '200's are just for the example. can anyone please tell me what I am doing wro开发者_开发技巧ng.

Thanks in advance.

What you're doing wrong is using AbsoluteLayout. :) Seriously, you really shouldn't use it; try using a FrameLayout instead.

However, to answer your question, you shouldn't call layout on it, do this instead:

AbsoluteLayout.LayoutParams params = (AbsoluteLayout.LayoutParams)start_it.getLayoutParams();
params.x = 200;
params.y = 200;
start_it.setLayoutParams(params);

Or with less code, you could do this instead:

start_it.setLayoutParams(new AbsoluteLayout.LayoutParams(
    start_it.getWidth(), start_it.getHeight(), 200, 200));