title: Suggestion for a change of a grid background of graph using an android plot library
body: <p>I want to make look like grid background as a full screen, <img src="https://i.stack.imgur.com/f42ba.gif" alt="[look like this image">.  </p>
  
  <p>...by using android plot library. Can anyone suggest a good implementation of that.</p>
  
  <p>I'm going to change bitmapshader by creating bitmap, to pass<br>
  <code>RectF rect = plot.getGraph().getGridRect();
          BitmapShader myShader = new BitmapShader(
                  Bitmap.createScaledBitmap(
                          BitmapFactory.decodeResource(
                                  getResources(),
                                  R.drawable.graph_background),
                          1,
                          (int) rect.height(),
                          false),
                  Shader.TileMode.REPEAT,
                  Shader.TileMode.REPEAT);
         Matrix m = new Matrix();
         m.setTranslate(rect.left, rect.top);
         myShader.setLocalMatrix(m);<br>
  plot.getGraph().getGridBackgroundPaint().setShader(myShader);</code></p>
  
  <p>this give error for  (int) rect.height(), null pointer exception for this</p>