NullPointerException & Update README

Author: BCsl

README.md

@@ -1,6 +1,6 @@
 # CursorWheelLayout
 
-CursorWheelLayout is an Android library that allows view to be placed on a rotatable wheel. It behaves like a Circular ListView where items rotate rather than scroll vertically.
+CursorWheelLayout is an Android library that allows view to be placed on a rotatable wheel. It behaves like a Circular ListView where items rotate rather than scroll vertically(but without view recycle strategy).
 CursorWheelLayout consists of two components , the center item with id `id_wheel_menu_center_item` and the menu items that provided by CycleWheelAdapter.
 
 The CursorWheelLayout can be used as a way to select one item from a list. The `wheelSelectedAngle` attribute determines what position on the wheel is selected.
@@ -111,7 +111,7 @@ public class SimpleTextAdapter implements CursorWheelLayout.CycleWheelAdapter{
   * wheelCursorHeight
   * wheelCursorColor
   * wheelBackgroundColor
-  * wheelRotateItem
+  * wheelItemRotateMode
 
 
 ## Refer to

library/src/main/java/github/hellocsl/cursorwheel/CursorWheelLayout.java

@@ -586,7 +586,7 @@ protected void dispatchDraw(Canvas canvas) {
             canvas.save();
             canvas.translate(mRootDiameter / 2f, mRootDiameter / 2f);
             View child = getChildAt(startIndex);
-            if (child != null) {
+            if (child != null && child.getTag(R.id.id_wheel_view_angle) != null) {
                 int startAngel = (int) (((Double) child.getTag(R.id.id_wheel_view_angle) + angleDelay / 2.f) % 360);
                 for (int i = startIndex; i < getChildCount(); i++) {
                     canvas.save();