IOS学习 Notification 用通知传值

#import <UIKit/UIKit.h>

#import "SecondViewController.h"

#define kCLTN @"ChangLabelTextNotification"   //通知名

#define VIEW_WIDTH self.view.bounds.size.width

#define VIEW_HEIGHT self.view.bounds.size.height

@interface HomeViewController : UIViewController

@end

@implementation HomeViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    

    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(VIEW_WIDTH/2-50, 300, 100, 40)];

    [btn setTitle:@"present" forState:UIControlStateNormal];

    btn.tintColor = [UIColor whiteColor];

    btn.backgroundColor = [UIColor purpleColor];

    [btn addTarget:self action:@selector(click) forControlEvents:UIControlEventTouchUpInside];

    [self.view addSubview:btn];

    

    UILabel *Label = [[UILabel alloc]initWithFrame:CGRectMake(VIEW_WIDTH/2-100, 160, 200, 40)];

    Label.backgroundColor = [UIColor orangeColor];

    Label.text = @"yihong";

    Label.tag = 102;

    [self.view addSubview:Label];

    

    //向数据中心了注册了一个通知，ChangLabelTextNotification

    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(changLabelText:) name:kCLTN object:nil];

}

//传值设置

- (void)changLabelText:(NSNotification *)notification {

    //根据tag查找label

    UILabel *label = (UILabel *)[self.view viewWithTag:102];

    label.text = notification.object;

}

//页面跳转

- (void)click {

    SecondViewController *secondVC = [[SecondViewController alloc]init];

    [self presentViewController:secondVC animated:YES completion:^{NSLog(@"present");}];

}

#import "HomeViewController.h"

@interface SecondViewController : UIViewController

{

@private

    UITextField *_textField;

}

@end

@implementation SecondViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view.

    

    _textField = [[UITextField alloc]initWithFrame:CGRectMake(VIEW_WIDTH/2-100, 160, 200, 40)];

    _textField.borderStyle = UITextBorderStyleRoundedRect;

    [self.view addSubview:_textField];

    

    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(VIEW_WIDTH/2-50, 300, 100, 40)];

    [btn setTitle:@"dismiss" forState:UIControlStateNormal];

    [btn addTarget:self action:@selector(dismiss) forControlEvents:UIControlEventTouchUpInside];

    btn.backgroundColor = [UIColor purpleColor];

    btn.layer.cornerRadius = 6;

    [self.view addSubview:btn];

}

- (void)dismiss{

    //监听homeVC上的通知

    [[NSNotificationCenter defaultCenter]postNotificationName:kCLTN object:_textField.text];

    //模态视图返回主页面

    [self dismissViewControllerAnimated:YES completion:^{

        NSLog(@"dismiss");}];

}