block简单回调

例如一个cell上的点击事件，通过block回调给控制器处理

cell头文件：

#import <UIKit/UIKit.h>

typedef void(^checkMessage)(NSInteger index);

@interface InformationCell : UITableViewCell

@property(nonatomic,copy) checkMessage clickBack;

@end

cell实现文件

#pragma mark - 点击事件
- (void)clickMessage:(UIButton *)button {
    NSInteger index = button.tag;
    self.clickBack(index);
}

block回调给控制器处理

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    __weak typeof(self) weakSelf = self;
    static NSString *cellId = @"informationCell";
    InformationCell *cell = [tableView dequeueReusableCellWithIdentifier:cellId];
    if (!cell) {
        cell = [[InformationCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellId];
    }
    NewsLastModel *model = _lastNewsDataSource[indexPath.row];
    cell.model = model;
    cell.clickBack = ^(NSInteger index) {
        __strong typeof(weakSelf) strongSelf = weakSelf;
        [strongSelf checkMessageWithIndex:index model:model];
    };
    return cell;
}