@interface ViewController ()
@property (weak, nonatomic) UILabel *label;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
UILabel *lb = [UILabel new];
_label = lb;
lb = nil;
//lb和_label都是nil
_label.text = @"";
}
@interface ViewController ()
@property (assign, nonatomic) UILabel *label;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
UILabel *lb = [UILabel new];
_label = lb;
lb = nil;
//lb是nil，_label不是nil，执行下面的方法会报错
_label.text = @"";
}
