code: public void setRotation(float w, float x, float y, float z) {
          getTransform().setRotation(w, x, y, z);
          if (mTransformCache.setRotation(w, x, y, z)) {
              onTransformChanged();
          }
      }
docs: Set rotation, as a quaternion.
  
  Sets the widget's current rotation in quaternion terms. Overrides any
  previous rotations using {@link #rotate(float, float, float, float)
  rotate()}, {@link #rotateByAxis(float, float, float, float)
  rotateByAxis()} , or
  {@link #rotateByAxisWithPivot(float, float, float, float, float, float, float)
  rotateByAxisWithPivot()} .
  
  @param w
  'W' component of the quaternion.
  @param x
  'X' component of the quaternion.
  @param y
  'Y' component of the quaternion.
  @param z
  'Z' component of the quaternion.