code: public String flattenToString() {
          StringBuilder sb = new StringBuilder(32);
          // WARNING: Do not change the format of this string, it must be
          // preserved because Rects are saved in this flattened format.
          sb.append(left);
          sb.append(' ');
          sb.append(top);
          sb.append(' ');
          sb.append(right);
          sb.append(' ');
          sb.append(bottom);
          return sb.toString();
      }
docs: Return a string representation of the rectangle in a well-defined format.
  
  You can later recover the Rect from this string through
  {@link #unflattenFromString(String)}.
  
  @return Returns a new String of the form "left top right bottom"