title: Transparent bitmap is black
body: <p>I have two overlapping imageviews. I want one to stay unchanged while the other one is completely transparent. I am drawing with canvas to the transparent one, but I can not get a transparent bitmap.  How can I rectify this?</p>
  
  <p>When I set its color closer to the transparent color (by diminishing alpha channel) using <code>bitmap.eraseColor(color)</code>, it becomes closer and closer to black. When I set it to <code>bm.eraseColor(Color.Transparent)</code> it appears completely black. The imageview that contains the bitmap has a transparent background, so I can show it from the outside of the black bitmap (which is supposed to transparent).</p>
  
  <pre><code>bm.add(decodeSampledBitmapFromResource(
      getIntent().getExtras().getString("filePath"),
      iv.getHeight(), iv.getWidth()).copy(
          Bitmap.Config.ARGB_8888, true));
  
      scaleBitmap();
  
      originalImage.setImageBitmap(bm.get(N).copy(
          Bitmap.Config.ARGB_8888, false));
  
      bm.get(N).eraseColor(Color.TRANSPARENT);
      iv.setImageBitmap(bm.get(N));
  </code></pre>
  
  <p>Here is the related part of the layout code:</p>
  
  <pre><code>&lt;RelativeLayout
      android:id="@+id/myImages"
      android:layout_width="fill_parent"
      android:layout_height="0dp"
      android:layout_weight="6"
       &gt;
  
      &lt;ImageView
          android:id="@+id/originalImage"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:paddingLeft="0dp"
          android:paddingRight="0dp"
          android:scaleType="centerInside"
          android:visibility="visible" /&gt;
  
      &lt;com.abacus.colorsketch.MyImageView
          android:id="@+id/workingImage"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:background="@android:color/transparent"
          android:paddingLeft="0dp"
          android:paddingRight="0dp"
          android:scaleType="centerInside" /&gt;
  &lt;/RelativeLayout&gt;
  </code></pre>