Objective-C ARC转换的几个问题

Question

我正在尝试将我的代码转换为Objective-C ARC并获得多个错误.

1:

NSBezierPath *path = [NSBezierPath bezierPath];
CGPathApply(pathRef,  path, CGPathCallback); //error

它说:使用ARC不允许将Objective.C指针隐式转换为'void*'

2:

static void CGPathCallback(void *info, const CGPathElement *element) {
NSBezierPath *path = info; //error
[…] }

它说:ARC不允许将非Objective-C指针类型'void*'隐式转换为'NSBezierPath*'

任何想法,我如何解决问题？

Answer 1

你需要使用桥接演员表.在这种情况下,您只需要简单的__bridge修饰符,例如

NSBezierPath *path = [NSBezierPath bezierPath];
CGPathApply(pathRef, (__bridge void *)path, CGPathCallback);

和

static void CGPathCallback(void *info, const CGPathElement *element) {
    NSBezierPath *path = (__bridge NSBezierPath*)info;
    ...
}