Android布局页面是黑色的，没有任何颜色或图像

Question

我想一个接一个地创建更多的LinearLayouts但我有问题，我只能看到黑页。怎么了。为什么我看不到图像？

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/drawer_layout"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">
                <LinearLayout
                    android:gravity="center"
                    android:orientation="vertical"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content">
                    <LinearLayout
                        android:id="@+id/featured_group"
                        android:background="@color/yellow"
                        style="@style/Home_Card_Group">
                        <ImageView
                            android:id="@+id/sponsored_topic_header"
                            android:visibility="gone"
                            android:layout_width="fill_parent"
                            android:src="@drawable/logo_icon"
                            android:layout_height="wrap_content"
                            android:scaleType="centerInside"
                            style="@style/Home_Card_Sponsored_Header" />
                        <ImageView
                            android:background="@drawable/bottom_shadow"
                            android:layout_width="fill_parent"
                            android:layout_height="16.0dip"
                            android:contentDescription="@string/shadow_desc" />
                    </LinearLayout>
                </LinearLayout>
               more LinearLayouts
        </RelativeLayout>
    </LinearLayout>

样式：

<style name="Home_Card_Group">
    <item name="android:gravity">center</item>
    <item name="android:orientation">vertical</item>
    <item name="android:visibility">gone</item>
    <item name="android:layout_width">fill_parent</item>
    <item name="android:layout_height">fill_parent</item>
</style>

<style name="Home_Card_Sponsored_Header">
    <item name="android:gravity">center</item>
    <item name="android:layout_gravity">center</item>
    <item name="android:layout_marginLeft">@dimen/default_edge_margin</item>
    <item name="android:layout_marginRight">@dimen/default_edge_margin</item>
</style>