• 兩個控制器之間傳值

傳送控制器需要添加的代碼

傳送的控制器.h

#import <UIKit/UIKit.h>
//定義Block類型
typedef void(^JFCityViewControllerBlock)(NSString *cityName);


@interface JFCityViewController : UIViewController

@property (nonatomic,copy) JFCityViewControllerBlock choseCityBlock;
- (void)choseCityBlock:(JFCityViewControllerBlock)block;

@end

傳送的控制器.m

//對應於.h文件中的方法,用來給需要接收的控制器調用,然後保存Block到self.choseCityBlock中
- (void)choseCityBlock:(JFCityViewControllerBlock)block {
    self.choseCityBlock = block;
}
...
//這裡開始調用Block,並將[cityData valueForKey:@"city"]字符串偉過去
        __weak typeof(self) weakSelf = self;
            if (weakSelf.choseCityBlock) {
                weakSelf.choseCityBlock([cityData valueForKey:@"city"]);
            }

接收控制器需要添加的代碼

      //只需要設置Block裏面需要做的事情,就等著傳送控制器有值後來調用了!
            [cityViewController choseCityBlock:^(NSString *cityName) {
                self.conditionView.cityName = cityName;
                self.city = cityName;
            }];