title: How to draw a moving line on android camera?
body: <p>I'd like to draw a moving line on a the camera for waiting the end of a process. For the moment I have this piece of code :</p>
  
  <pre><code> public class OcrGraphic extends GraphicOverlay.Graphic {
  
      OcrGraphic(GraphicOverlay overlayt) {
          super(overlay);
          postInvalidate();
      }
  
      @Override
      public void draw(Canvas canvas) {
           //draw line
      }
  }
  </code></pre>
  
  <p>The issue is that I don't want to draw the line only once but I want to create something like a thread in the purpose of moving the line (up and down) during a long process.</p>
  
  <p>Here is the XML I have : </p>
  
  <pre><code>    &lt;com.google.android.gms.samples.vision.ocrreader.ui.camera.CameraSourcePreview
          android:id="@+id/preview"
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
  
          &lt;com.google.android.gms.samples.vision.ocrreader.ui.camera.GraphicOverlay
              android:id="@+id/graphicOverlay"
              android:layout_width="match_parent"
              android:layout_height="match_parent" /&gt;
          &lt;View
              android:layout_width="5dp"
              android:layout_height="1dp"
              android:background="#FF0000"
              android:id="@+id/line"
              android:layout_alignParentTop="true"
              android:layout_alignParentLeft="true"
              android:layout_alignParentStart="true"
              android:layout_marginTop="65dp"
              android:minHeight="5dp" /&gt;
  
      &lt;/com.google.android.gms.samples.vision.ocrreader.ui.camera.CameraSourcePreview&gt;
  </code></pre>
  
  <p>The 'camereSourcePreview' tag comes from the google vision API.</p>