title: Android custom RatingBar image artifacts
body: <p>I implemented a custom <code>RatingBar</code> in an application on my <code>ListView</code> items.
  Custom style <strong>ratingbar_red.xml</strong>:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;layer-list xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:id="@android:id/background" android:drawable="@drawable/star_off" /&gt;
      &lt;item android:id="@android:id/secondaryProgress" android:drawable="@drawable/star_on" /&gt;
      &lt;item android:id="@android:id/progress" android:drawable="@drawable/star_on" /&gt;
  &lt;/layer-list&gt;
  </code></pre>
  
  <p>Here's part of ListItem layout:</p>
  
  <pre><code>&lt;LinearLayout
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:orientation="horizontal"
      android:paddingLeft="15dp" &gt;
  
      &lt;RatingBar
          android:id="@+id/li_company_rating"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginTop="15dp"
          android:layout_marginBottom="1dp"
          android:isIndicator="true"
          android:numStars="5"
          android:progressDrawable="@drawable/ratingbar_red"
          android:stepSize="1" /&gt;
  
      &lt;Button
          android:id="@+id/li_company_callbtn"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginBottom="0dp"
          android:layout_marginLeft="40dp"
          android:contentDescription="@string/ContentDescription"
          android:drawableLeft="@drawable/phone_icon"
          android:drawablePadding="5dp"
          android:onClick="callbtn_Click"
          android:text="@string/CallButton"
          android:focusable="false"
          android:focusableInTouchMode="false" &gt;
      &lt;/Button&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>It works, but when the rating is set, I get some strange image artifacts; 2 vertical lines below the pink stars appear on my view: </p>
  
  <p><img src="https://i.stack.imgur.com/bhJ4t.png" alt="enter image description here"></p>
  
  <p>Here is <strong>star_on.png</strong> </p>
  
  <p><img src="https://i.stack.imgur.com/aaz3k.png" alt="link"></p>
  
  <p><strong>star_off.png</strong> looks okay, and if rating == 0, the lines don't appear.</p>
  
  <p>I'm android beginner, and can't understand what the problem is.</p>