使用Block传值的常用实例

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这里写图片描述

问题：viewControllerB需要拿到viewControllerA的itemView里的Model，进行相应的信息设置。Model该如何传递过去？

/*
Model –> ItemView –> ListView : [itemClick:] —> A : [itemClickBlock(model) ] —> A : [performSegueWithIdentifier:sender] —> A : [ prepareForSegue:] –> B
*/

ItemView

@interface ItemView : UIView@property (nonatomic, strong) Model *model;@end

Model

@interface Model : NSObject@property (nonatomic, copy) NSString *icon;@property (nonatomic, copy) NSString *title;@property (nonatomic, copy) NSString *intro;@end

ListView

@interface ListView : UIScrollView// 定义一个block进行传值， 要想拥有一个block属性，只能用copy @property (nonatomic, copy) void (^itemClickBlock)(Model *model);@end@implementation ListView- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        // 加载关卡信息        [self loadStageInfo];    }    return self;}-(void)loadStageInfo{    //先取出itemView。。。。    [itemView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(itemClick:)]];}#pragma mark 点击了关卡- (void)itemClick:(UITapGestureRecognizer *)tap{    if (_itemClickBlock) {        ItemView *itemView =  (ItemView *)tap.view;        _itemClickBlock(itemView.model);    }}@end

ViewControllerA

@implementation ViewControllerA- (void)viewDidLoad{    [super viewDidLoad];    // 2.添加ListView    ListView *listView = [[ListView alloc] initWithFrame:self.view.bounds];    listView.itemClickBlock = ^(Model *model){        // MyLog(@"%@", model.title); 这里就可以拿到model里的属性        [self performSegueWithIdentifier:@"segue" sender:model];    };    // 这里用insert保证listView在最下层    [self.view insertSubview:listView atIndex:0];}#pragma mark 跳转之前会调用（一般在这里传递数据给下一个控制器）- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{    ViewControllerB *ready = segue.destinationViewController;    ready.model = sender;}

ViewControllerB

#import <UIKit/UIKit.h>@class Model;@interface ViewControllerB : UIViewController// 关卡信息@property (nonatomic, strong) Model *model; //model传进来可以赋值了@property (weak, nonatomic) IBOutlet UILabel *stageNo;@property (weak, nonatomic) IBOutlet UILabel *stageIntro;@property (weak, nonatomic) IBOutlet UIImageView *stageIcon;- (IBAction)back;@end

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