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  • block传值

      定义block和定义delegate一样,都是在得到需要的值那个页面的类里定义。

      eg:A类、B类,我要将A类中的值传给B类,那么我就到A类中定义block,B类取值就可以了。。。。

      

      For example:

    第一步:

      A类中:

        .h文件:

        #import "BaseViewController.h"

         //定义块

    typedef void (^addCommunity)(UIImage *img,NSString *title);

    @interface MoreViewController : BaseViewController

    @property(nonatomic,copy)addCommunity adds;        注:定义block的属性一定要用copy

    -(void)addCommunityWithBlock:(addCommunity)addBlock;

    .m文件:

    - (void)viewDidLoad

    {

        [super viewDidLoad];

    // Do any additional setup after loading the view.

        imgView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];

        NSString *img = @"market-android.png";

        imgView.image = [UIImage imageNamed:img];

        [self.view addSubview:imgView];

     

        lblTitle = [[UILabel alloc]initWithFrame:CGRectMake(135, 230, 100, 30)];

        lblTitle.text = @"标题";

        lblTitle.textColor = [UIColor redColor];

        [self.view addSubview:lblTitle];

        

        UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100, 300, 100, 30)];

        [btn setTitle:@"添加" forState:UIControlStateNormal];

        [btn addTarget:self action:@selector(add) forControlEvents:UIControlEventTouchUpInside];

        [btn setBackgroundColor:[UIColor redColor]];

        [self.view addSubview:btn];

    }

    -(void)add{

        _adds(imgView.image,lblTitle.text);  //block传值

        

        [self.navigationController popToRootViewControllerAnimated:YES];

    }

    -(void)addCommunityWithBlock:(addCommunity)addBlock{

        _adds = addBlock;

    }

    第二步:

      B类中:

        .m文件:

    [more addCommunityWithBlock:^(UIImage *img,NSString *title){

                    NSDictionary *dic = [NSDictionary dictionaryWithObject:img forKey:title];

                }];

    在你需要用到值的地方,调用block,说明:more是A类的一个别名。这样就把B页面的值传到了A页面的NSDictionary中。。。。。。。我觉得写得还算清楚吧!嘿嘿......

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  • 原文地址:https://www.cnblogs.com/xumei/p/3847386.html
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