SeekBar拇指背景问题

Question

附上图片以供参考Image Screenshot

请在下面找到我的布局代码。我是android的新手。想学习......过去几天坚持这个......

我不希望看到背景为白色的拇指

如果需要任何细节，请告诉我.. 附上图片以供参考

Thumb.xml:
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape = "oval"
    android:tintMode="multiply">
    <gradient
        android:angle="360"
        android:endColor="@color/colorPrimaryDark"
        android:startColor="@color/colorPrimaryDark" />
    <size
        android:height="5dp"
        android:width="5dp"/>
</shape>


SeekBar:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:id="@android:id/background">
        <shape android:shape="rectangle">
            <corners android:radius="5dp"/>
            <gradient
                android:endColor="#6c6e6a"
                android:startColor="#61635f" />
        </shape>
    </item>
  <item android:id="@android:id/secondaryProgress">
        <clip>
            <shape android:shape="rectangle" >
                <corners android:radius="5dp" />
                <gradient
                    android:endColor="#303F9F"
                    android:startColor="#303F9F" />
            </shape>
        </clip>
    </item>
    <item android:id="@android:id/progress">
        <clip>
            <shape android:shape="rectangle" >
                <corners android:radius="5dp" />
                <gradient
                    android:endColor="#303F9F"
                    android:startColor="#303F9F"  />
            </shape>
        </clip>
    </item>
</layer-list>



Content:
<SeekBar
        android:id="@+id/ProgressBar"
        android:layout_width="fill_parent"
        android:layout_height="20dp"
        android:progress="20"
        android:progressDrawable="@drawable/seekbar_size"
        android:thumb="@drawable/thumb3"
       />