码迷,mamicode.com
首页 > 其他好文 > 详细

KVO(1)

时间:2015-06-30 15:01:15      阅读:104      评论:0      收藏:0      [点我收藏+]

标签:kvo

#import "ViewController.h"

@interface ViewController ()
@property(nonatomic, strong)UIButton *button;


@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.button = [[UIButton alloc] initWithFrame:CGRectMake(30, 50, 50, 30)];
    [self.button setTitle:@"测试" forState:UIControlStateNormal];
    [self.button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    self.button.layer.borderWidth = 1.0f;
    [self.view addSubview:self.button];

    //注册监听button的enabled状态
    [self.button addObserver:self forKeyPath:@"enabled" options:NSKeyValueObservingOptionNew context:@"test_button"];

    //  3秒钟后改变当前button的enabled状态
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3.0f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        self.button.enabled = YES;
    });
    // Do any additional setup after loading the view, typically from a nib.
}

/**
 *  监听按钮状态改变的方法
 *
 *  @param keyPath 按钮改变的属性
 *  @param object  按钮
 *  @param change  改变后的数据
 *  @param context 注册监听时context传递过来的值
 */
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    UIButton *button = (UIButton *)object;
    if (self.button == button && [@"enabled" isEqualToString:keyPath]) {
        NSLog(@"self.button的enabled属性改变了%@",[change objectForKey:@"new"]);
    }
}

版权声明:本文为博主原创文章,未经博主允许不得转载。

KVO(1)

标签:kvo

原文地址:http://blog.csdn.net/tubiebutu/article/details/46694609

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!