iOS反向传值

代理传值

要展示的控制器

• 需要准守<ALTargetViewControllerDeleagte>协议
• 实现(void)text:(NSString *)text fromVC:(ALTargetViewController *)fromVC indexPath:(nonnull NSIndexPath *)indexPath方法

@interface ALMainViewController ()<ALTargetViewControllerDeleagte>
@end

#pragma mark - ALTargetViewControllerDeleagte

- (void)text:(NSString *)text fromVC:(ALTargetViewController *)fromVC indexPath:(nonnull NSIndexPath *)indexPath
{
    UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
    cell.detailTextLabel.text = text;
}

要反向传值的控制器

• .h文件需要声明协议，提供一个对外delegate属性，只需要准守我的协议就能成为我的代理对象

@protocol ALTargetViewControllerDeleagte <NSObject>
@optional
- (void)text:(NSString *)text fromVC:(ALTargetViewController *)fromVC indexPath:(NSIndexPath *)indexPath;
@end
@interface ALTargetViewController : UIViewController


@property (nonatomic, weak)id <ALTargetViewControllerDeleagte> delegate;
@end

• .m文件传递展示控制器需要的内容

- (IBAction)onButton:(id)sender {
    if ([self.delegate respondsToSelector:@selector(text:fromVC:indexPath:)]) {
        [self.delegate text:self.textField.text fromVC:self indexPath:self.indexPath];
    }
    [self.navigationController popViewControllerAnimated:YES];
}

通知传值

要展示的控制器

• 添加观察者addObserver:
• 实现通知回调传回的内容(void)alNotification:(NSNotification *)noti

- (void)viewDidLoad {
    [super viewDidLoad];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alNotification:) name:@"ALNotification" object:nil];
}
#pragma mark - Notice
- (void)alNotification:(NSNotification *)noti {
    NSDictionary *dict     = noti.object;
    NSString *text         = dict[@"text"];
    NSIndexPath *indexPath = dict[@"indexPath"];
    UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
    cell.textLabel.text = text;
}

要反向传值的控制器

- (IBAction)onButton:(id)sender {
    [[NSNotificationCenter defaultCenter] postNotificationName:@"ALNotification" object:@{@"text":_textField.text, @"indexPath": self.indexPath}];
    [self.navigationController popViewControllerAnimated:YES];
    
}