block的界面间传值的使用

 1 #import "MainListBaseViewController.h"
 2 
 3 typedef void(^ChangePlayViewBlock)(NSDictionary *);
 4 
 5 @interface RadioDPlayViewController : MainListBaseViewController
 6 
 7 
 8 @property (nonatomic, copy) ChangePlayViewBlock changePlayVBlock;
 9 
10 
11 @end

 1 - (void)viewDidLoad {
 2     [super viewDidLoad];
 3      self.view.backgroundColor = [UIColor grayColor];
 4     
 5     [self createMainView];
 6     
 7     //创建数组注意放在tableView的上面。
 8     [self createDataSourceArray];
 9     //注意创建添加顺序，先加TableView，再加右视图控制器。
10     [self createMainListTableView];
11     [self createRightView];
12 
13 // 在这里接受名字为“DPlayVC有值了”的通知，接受到从视图控制器A传过来的通知后执行"assignToBlock:"方法，即self.DPlayVC有了正确的值即指向当前的视图控制器A后再给self.DPlayVC.changePlayVBlock()赋值，此时视图控制器A里的changePlayVBlock()属性就能赋上值了。在视图控制器A里面的showPlayView:方法里调用changePlayVBlock()时就可以有效执行changePlayVBlock()里的内容即这里给changePlayVBlock()赋得值。
14     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(assignToBlock:) name:@"DPlayVC有值了" object:nil];
15     
16 }
17 
18 
19 - (void)assignToBlock:(NSNotification *)notification
20 {
21     self.DPlayVC.changePlayVBlock = ^void(NSDictionary *dic){
22         
23         [self.musicImage setImage:[dic objectForKey:@"playImgView"]];
24         self.musicNameLabel.text = [dic objectForKey:@"title"];
25         self.artistLabel.text = [dic objectForKey:@"artist"];
26         [self.playBtn setBackgroundImage:[UIImage imageNamed:@"iconfont-bofang-1"] forState:UIControlStateNormal];
27     };
28 }

 1 - (void)showPlayView:(NSInteger)index
 2 {
 3     [self.playImageView sd_setImageWithURL:[NSURL URLWithString:[[self.musicListTableViewArray[index] playInfo] objectForKey:@"imgUrl"]]];
 4 
 5     self.titleLabel.text = [[self.musicListTableViewArray[index] playInfo] objectForKey:@"title"];
 6 
 7     self.likeLabel.text = [NSString stringWithFormat:@"%@",self.model.like];
 8 
 9     self.commentLabel.text = [NSString stringWithFormat:@"%@",self.model.comment];
10     
11     
12     NSString *artistText = [[[self.musicListTableViewArray[index] playInfo] objectForKey:@"authorinfo"] objectForKey:@"uname"];
13     NSDictionary *dic = @{@"playImgView":self.playImageView.image,@"title":self.titleLabel.text,@"artist":artistText};
14     
15     
16     self.rootLeftVC.DPlayVC = self;
17     
18 // 给通知中心添加一个通知，当self.rootLeftVC.DPlayVC有值时，向外界发送一个名字即name为"self.rootLeftVC.DPlayVC有值了"的通知，凡名字为此的都可以接受到这个通知。此时在视图控制器B里面就接收到了这个通知，并给self.DPlayVC.changePlayVBlock()赋值，此时self.DPlayVC有值并指向正确的此视图控制器，所以block可以赋上值。
19     [[NSNotificationCenter defaultCenter] postNotificationName:@"DPlayVC有值了" object:self userInfo:nil];
20     
21     
22     if (_changePlayVBlock) {
23         _changePlayVBlock(dic);
24         
25     }
26 
27 }