title: How to set transparent Activity in android 6.0
body: <p>I have a Activity,and I set it's launchMode is singleInstance. now I set it's background transparent .but when I start it in setting ,it's background is black.
  so ,what should I do.below is my code</p>
  
  <p>in style:</p>
  
  <pre><code>&lt;style name="translucent" parent="Theme.AppCompat"&gt;
      &lt;item name="android:windowBackground"&gt;@color/translucent_background&lt;/item&gt;
      &lt;item name="android:windowIsTranslucent"&gt;true&lt;/item&gt;
   &lt;itemname="android:windowAnimationStyle"&gt;@android:style/Animation.Translucent&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>in androidManifest</p>
  
  <pre><code>&lt;activity
          android:name=".main.activity.AssisTipsActivity"
          android:screenOrientation="portrait"
          android:launchMode="singleInstance"
          android:theme="@style/translucent"/&gt;
  </code></pre>