void clear() {
      view = null;
      layer = -1;
    }
Renders your view hierarchy as an interactive 3D visualization of layers.
<p>
Interactions supported:
<ul>
<li>Single touch: controls the rotation of the model.</li>
<li>Two finger vertical pinch: Adjust zoom.</li>
<li>Two finger horizontal pinch: Adjust layer spacing.</li>
</ul>
saklib/src/main/java/com/wanjian/sak/layer/impl/ScalpelFrameLayout.java