NSNotificationCenter对象UILabel

Question

这段代码有什么问题...

[选择器名称：@NSNotificationCenter(MySubViewNotification：) defaultCenter：@“MySubViewNotification”object:nil]；

 -(void)MySubViewNotification:(UILabel*)GenericLabel
 {

    GenericLabel.textColor = [UIColor whiteColor]; ---- Error ----
    GenericLabel.text = @"cwxcwxc"; ---- Error ----

    NSLog(@"%@", GenericLabel);
 }

 NSLog.

 NSConcreteNotification 0x1759c6c0 {name = MySubViewNotification; object = <UILabel: 0x175aace0; frame = (175 5; 62 15); text = '1.35'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x175aad80>>}

 Errror

-[NSConcreteNotification setText:]: unrecognized selector sent to instance 0x165a4270
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSConcreteNotification setText:]: unrecognized selector sent to instance 0x165a4270'

Answer 1

您的通知调用的方法应具有签名：

- (void)mySubViewNotification:(NSNotification *)note

(请注意，第一个字母小写的标准类名称以大写开头，方法以小写开头，相应地更新代码，参数为通知)

然后，您可以在该方法中添加：

UILabel *label = note.object;
label.textColor = [UIColor whiteColor];

因为通知是作为参数传递给您的，您需要从它获取封装的信息(在本例中是标签)。