Margin ignored by LinearLayout

Question

I'm creating dynamically views containing a LinearLayout and add them to an outer LinearLayout. I would like to set a margin around the created views, but the layout_margin in the XML file is ignored. It works, if I set the parameters in the code, but I would like to specify the margin in the layout XML.

Setting the margin in the XML layout will be ignored:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="20dp"
    android:orientation="vertical" >

    ...
</LinearLayout>

Setting the margin while creating is honored:

LinearLayout productView = (LinearLayout) getLayoutInflater().inflate(R.layout.product_preview, null);

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
params.setMargins(50, 50, 50, 50);  
productView.setLayoutParams(params);

This is the outer layout. The views are added to dealer_activity_product_list.

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/dealer_activity_dealer_image"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:contentDescription="@string/dealer_activity_dealer_image_desc" />

    <TextView
        android:id="@+id/dealer_activity_dealer_address"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <LinearLayout
            android:id="@+id/dealer_activity_product_list1"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:orientation="vertical" />

        <LinearLayout
            android:id="@+id/dealer_activity_product_list2"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:orientation="vertical" />
    </LinearLayout>
</LinearLayout>

Answer 1

Are you setting the attribute for the inner LinearLayout or the containing LinearLayout? At least, the following does work inside a LinearLayout:

<TextView
    android:id="@+id/xxx"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="20sp"
    android:layout_margin="10dp"
    />