仅做记录，一个函数和字符串之间的互相转换
方法如下：
UIKIT_EXTERN NSString *NSStringFromCGPoint(CGPoint point);
UIKIT_EXTERN NSString *NSStringFromCGVector(CGVector vector);
UIKIT_EXTERN NSString *NSStringFromCGSize(CGSize size);
UIKIT_EXTERN NSString *NSStringFromCGRect(CGRect rect);
UIKIT_EXTERN NSString *NSStringFromCGAffineTransform(CGAffineTransform transform);
UIKIT_EXTERN NSString *NSStringFromUIEdgeInsets(UIEdgeInsets insets);
UIKIT_EXTERN NSString *NSStringFromUIOffset(UIOffset offset);
UIKIT_EXTERN CGPoint CGPointFromString(NSString *string);
UIKIT_EXTERN CGVector CGVectorFromString(NSString *string);
UIKIT_EXTERN CGSize CGSizeFromString(NSString *string);
UIKIT_EXTERN CGRect CGRectFromString(NSString *string);
UIKIT_EXTERN CGAffineTransform CGAffineTransformFromString(NSString *string);
UIKIT_EXTERN UIEdgeInsets UIEdgeInsetsFromString(NSString *string);
UIKIT_EXTERN UIOffset UIOffsetFromString(NSString *string);例子：
结构体转字符串：
NSString *NSStringFromCGPoint(CGPoint point);
NSString *NSStringFromCGVector(CGVector vector);
NSString *NSStringFromCGSize(CGSize size);
NSString *NSStringFromCGRect(CGRect rect);
NSString *NSStringFromCGAffineTransform(CGAffineTransform transform);
NSString *NSStringFromUIEdgeInsets(UIEdgeInsets insets);
NSString *NSStringFromUIOffset(UIOffset offset);字符串转 结构体：
CGPoint CGPointFromString(NSString *string);
CGVector CGVectorFromString(NSString *string);
CGSize CGSizeFromString(NSString *string);
CGRect CGRectFromString(NSString *string); //我们在监听高度变化时需要用这个 ,获取键盘的frame 值,就是从一个 string类型中取出 CGRect!
CGAffineTransform CGAffineTransformFromString(NSString *string);
UIEdgeInsets UIEdgeInsetsFromString(NSString *string);//距离边界的距离,上左下右的顺序!
UIOffset UIOffsetFromString(NSString *string);
