title: How to remove thick white border on the top end and bottom end of android spinner?
body: <p>I have built my app using react-native and there is a picker component in it. I have styled it using styles.xml but there is a white thick border on both ends of the dorpdown which I want to remove. I have tried almost everything - even setting both padding and margin to 0 but the top and bottom white thick border don't disappear. Can somebody point out how to remove them?</p>
  
  <p><a href="https://i.stack.imgur.com/iQbWU.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iQbWU.jpg" alt="enter image description here"></a></p>
  
  <p>My Code:  /res/values/styles.xml</p>
  
  <pre><code>&lt;style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar"&gt;
    &lt;item name="android:spinnerItemStyle"&gt;@style/SpinnerItem&lt;/item&gt;
    &lt;item name="android:spinnerDropDownItemStyle"&gt;@style/SpinnerDropDownItem&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="SpinnerItem" parent="Theme.AppCompat.Light.NoActionBar"&gt;&gt;
    &lt;item name="android:fontFamily"&gt;sans-serif-light&lt;/item&gt;
    &lt;item name="android:textSize"&gt;18dp&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="SpinnerDropDownItem" parent="Theme.AppCompat.Light.NoActionBar"&gt;&gt;
      &lt;item name="android:textColor"&gt;#ffffff&lt;/item&gt;
      &lt;item name="android:textSize"&gt;18dp&lt;/item&gt;
      &lt;item name="android:fontFamily"&gt;sans-serif-light&lt;/item&gt;
      &lt;item name="android:gravity"&gt;center&lt;/item&gt;
      &lt;item name="android:background"&gt;@drawable/mydivider&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>Code at res/drawable/mydivider.xml:</p>
  
  <pre><code>&lt;shape xmlns:android="http://schemas.android.com/apk/res/android"
      android:shape="rectangle"&gt;
      &lt;solid android:color="#29A1C9" /&gt;
      &lt;corners android:radius="0.5dp" /&gt;
      &lt;stroke
          android:color="#FFFFFF"
          android:width="0.1dp" /&gt;
  &lt;/shape&gt;
  </code></pre>
  
  <p>React native picker code:</p>
  
  <pre><code> &lt;Picker
        style={{color: darkTextColor, marginLeft:12}}
        ref={this.refId()}
        selectedValue={this.props.application.typeOfBusiness}
        onValueChange={(toi) =&gt; this.onUpdate('typeOfBusiness', toi)}&gt;
        {typeOfBusinessLabels.map((val)=&gt; &lt;Picker.Item key={val} label={val} value={val}/&gt;)}
   &lt;/Picker&gt;`
  </code></pre>