自定义ProgressBar格式

<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="80dp"
android:layout_height="20dp"
android:max="100"
android:progress="30"
android:progressDrawable="@drawable/progressbar"
android:visibility="visible"/>

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:id="@android:id/background">
<shape>
<corners android:radius="5dip" />
<gradient
android:angle="0"
android:centerColor="#ff5a5d5a"
android:centerY="0.75"
android:endColor="#ff747674"
android:startColor="#ff9d9e9d" />
</shape>
</item>

<item android:id="@android:id/secondaryProgress">
<clip>
<shape>
<corners android:radius="5dip" />
<gradient
android:angle="0"
android:centerColor="#80ffb600"
android:centerY="0.75"
android:endColor="#a0ffcb00"
android:startColor="#80ffd300" />
</shape>
</clip>
</item>

<item android:id="@android:id/progress">
<clip>
<shape>
<corners android:radius="5dip" />

<gradient
android:angle="0"
android:endColor="#8000ff00"
android:startColor="#8000ff00" />
</shape>
</clip>
</item>

</layer-list>