使用NSCoder编码CGPoint结构

Question

如何使用NSCoder编码和解码CGPoint结构？

Answer 1

编码:

CGPoint point = /* point from somewhere */
NSValue *pointValue = [NSValue value:&point withObjCType:@encode(CGPoint)];
[coder encodeObject:pointValue forKey:@"point"];

要解码:

NSValue *decodedValue = [decoder decodeObjectForKey:@"point"];
CGPoint point;
[decodedValue getValue:&point];

Answer 2

只是iOS开发人员的更新.您可以在Cocoa Touch中执行以下操作(但不能在Cocoa中执行):

[coder encodeCGPoint:myPoint forKey:@"myPoint"];

Answer 3

CGPoints和NSPoints都是由两个CGFloat值组成的结构,因此你可以自由地将它们相互传递.快速而肮脏的方式是:

NSCoder *myNSCoder;
CGPoint myPoint;
[myNSCoder encodePoint:*(NSPoint *)myPoint];

这通常可以工作,但它在技术上打破了C99严格的别名规则.如果您想与标准100%兼容,您必须执行以下操作:

typedef union
{
  CGPoint cgPoint;
  NSPoint nsPoint;
} CGNSPoint;

CGNSPoint cgnsPoint = { .cgPoint = myPoint };
[myNSCoder encodePoint:cgnsPoint.nsPoint];