button below other button programmatically android

i have in xml tis code:

<RelativeLayout 
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/mainLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

    <Button
        android:id="@+id/examp1"
        android开发者_StackOverflow:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/examp2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/examp1" />
</RelativeLayout>

I want to create these buttons programmatically and i use:

RelativeLayout mainLayout;
mainLayout = (RelativeLayout) findViewById(R.id.mainLayout);

for (int i=0; i<1; i++)
{
     Button new_button = new Button(this);
     new_button.setText("blabla");
     new_button.setId(i);
     new_button.setLayoutParams(new LayoutParams(
                        ViewGroup.LayoutParams.WRAP_CONTENT,         
                        ViewGroup.LayoutParams.WRAP_CONTENT));

     mainLayout.addView(new_button);
}

How can I translate this command android:layout_below="@id/examp1" programmatically?

Use RelativeLayout.LayoutParams. Use addRule(), for your example use it with RelativeLayout.BELOW and the id (R.id.examp1)