ios - 如何通过运行时方法object_getIvar从结构的点变量获取值

标头：

@interface DisplayConnection : NSObject
{
    UIView *_view;
    struct UnityDisplaySurfaceBase *_surface;
}
@property(readonly, nonatomic) struct UnityDisplaySurfaceBase *surface;
@property(readonly, copy, nonatomic) UIView *view;
@end

我可以得到_view的值：id value = object_getIvar(instance, _viewIvar);
但是在object_getIvar(instance, _surfaceIvar)时崩溃，并且无法捕获异常。

帮助，谢谢。

最佳答案

我只是解决了这个问题。该解决方案适用于C基本类型/结构。
id不能指向struct。

@interface DisplayConnection : NSObject
{
    UIView *_view;
    struct UnityDisplaySurfaceBase _surface;//without pointer value
}
@property(readonly, nonatomic) struct UnityDisplaySurfaceBase surface;
@property(readonly, copy, nonatomic) UIView *view;
@end
@implementation DisplayConnection
- (UnityDisplaySurfaceBase)someValue {



Ivar inner = class_getInstanceVariable ([self class], "_surface");
ptrdiff_t offset = ivar_getOffset(inner);
unsigned char *stuffBytes = (unsigned char *)(__bridge void *)self;
UnityDisplaySurfaceBase someVar = * ((UnityDisplaySurfaceBase *)(stuffBytes + offset));

return  someVar;
}
@end

参考：https://stackoverflow.com
参考：https://www.bignerdranch.com