-(void)control
{
self.person = [[Person alloc]init];
self.person.book = [[Book alloc]init];
[self.person setValue:@"lili" forKey:@"name"];
[self.person setValue:@"20" forKey:@"age"];
[self.person setValue:@"200" forKey:@"height"];
[self.person setValue:@"ios" forKeyPath:@"book.bookName"];
[self.person setValue:@"11.5" forKeyPath:@"book.price"];
//註冊觀察者
[self.person addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew context:nil];
self.label = [[UILabel alloc]initWithFrame:CGRectMake(100, 100, 100, 30)];
[self.label setText:[self.person valueForKey:@"name"]];
[self.view addSubview: self.label];
self.button = [UIButton buttonWithType:UIButtonTypeCustom];
[self.button setTitle:@"點擊" forState:UIControlStateNormal];
[self.button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[self.button addTarget:self action:@selector(click) forControlEvents:UIControlEventTouchUpInside];
[self.button setFrame:CGRectMake(100, 200, 100, 30)];
[self.view addSubview:self.button];
}
-(void)click
{
[self.person setValue:@"aa" forKey:@"name"];
}
-(void)dealloc
{
//移除觀察者
[self.person removeObserver:self forKeyPath:@"name"];
}
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
{
if ([keyPath isEqualToString:@"name"]) {
[self.label setText:[self.person valueForKey:@"name"]];
}
}