ios开发 Block(二) 实现委托

浏览数：33 / 时间：2015年06月11日

委托和block是IOS上实现回调的两种机制。Block基本可以代替委托的功能，而且实现起来比较简洁，比较推荐能用block的地方不要用委托。

实现效果如图

第一步，自定义CustomCell

 1 #import <Foundation/Foundation.h>
 2 
 3 @interface CustomCell : UITableViewCell
 4 
 5 @property (strong, nonatomic) IBOutlet UILabel *labName;
 6 @property (copy,nonatomic) void(^BuyGoods)(NSString *);
 7 
 8 - (IBAction)ButtonBuyPressed:(id)sender;
 9 
10 @end

 1 #import "CustomCell.h"
 2 
 3 @implementation CustomCell
 4 
 5 
 6 
 7 - (IBAction)ButtonBuyPressed:(id)sender {
 8     
 9     NSString *goodName=_labName.text;
10     _BuyGoods(goodName);
11     
12 }
13 
14 @end

在custom.h文件里面有

@property (copy,nonatomic) void(^BuyGoods)(NSString *);

声明了一个block变量

在custom.m文件里面回调

NSString *goodName=_labName.text;

_BuyGoods(goodName);

下面看实现的类里面

 1 #import "ViewController.h"
 2 #import "CustomCell.h"
 3 
 4 @interface ViewController ()
 5 
 6 @end
 7 
 8 @implementation ViewController
 9 
10 - (void)viewDidLoad
11 {
12     [super viewDidLoad];
13     // Do any additional setup after loading the view, typically from a nib.
14     
15     _tabGoods.delegate=self;
16     _tabGoods.dataSource=self;
17 }
18 
19 - (void)didReceiveMemoryWarning
20 {
21     [super didReceiveMemoryWarning];
22     // Dispose of any resources that can be recreated.
23 }
24 
25 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
26 {
27     static NSString *CellIdentifier = @"CustomCell";
28     CustomCell *cell = (CustomCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
29     if (cell == nil) {
30         NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomCell" owner:self options:nil];
31         cell = [nib objectAtIndex:0];
32     }
33     cell.labName.text = [NSString stringWithFormat:@"商品名称%d",indexPath.row];
34     __block NSString *tipMsg=cell.labName.text;
35     cell.BuyGoods=^(NSString *str){
36         UIAlertView *alertView=[[UIAlertView alloc]initWithTitle:@"提示内容" message:tipMsg delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:nil, nil];
37         [alertView show];
38     };
39     
40     return cell;
41 }
42 
43 -(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
44     return 1;
45 }
46 
47 -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
48     return 10;
49 }
50 
51 @end