通知模式实现两个textField传值及模态视图——iOS开发

利用通知模式，实现两个不同界面的textField之间的传值，在界面二输入字符，传值到前一界面的textField。

界面的切换，这里临时先用模态视图实现。（重点在传值。所以没纠结设计界面排版。丑了点大家见谅）

大家不要看代码看上去好像挺多。由于我没使用storyboard/xib，是代码实现布局，所以通知和模态视图切换的代码非常少~

点击下一页按钮，进入界面二：

在textField处输入字符串：

点击返回按钮，回到界面一。此时界面一的textField处也有字符串

#import "AppDelegate.h"
#import "ViewController1.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];

    ViewController1 *vc1 = [[ViewController1 alloc] init];
    self.window.rootViewController = vc1;

    return YES;
}

#import "ViewController1.h"
#import "ViewController2.h"

@interface ViewController1 ()
{
    UITextField *text1;
}
@end

@implementation ViewController1

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor greenColor];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 50)];
    label.text = @"界面一";
    [self.view addSubview:label];

    text1 = [[UITextField alloc] initWithFrame:CGRectMake(50, 150, 100, 50)];
    text1.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:text1];

    UIButton *button1 = [[UIButton alloc] initWithFrame:CGRectMake(50, 250, 100, 50)];
    [button1 addTarget:self action:@selector(pushButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [button1 setTitle:@"下一页" forState:UIControlStateNormal];
    button1.backgroundColor = [UIColor blackColor];
    [self.view addSubview:button1];

//    注冊观察者
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(returnAction:) name:@"chuanzhi" object:nil];

    // Do any additional setup after loading the view.
}

- (void)returnAction:(NSNotification *)text {
    text1.text = text.userInfo[@"returnInfo"];
}

- (void)pushButtonAction:(UIButton *)btn {
    ViewController2 *vc2 = [[ViewController2 alloc] init];
    vc2.modalPresentationStyle = UIModalPresentationFullScreen;  //切换效果
    [self presentViewController:vc2 animated:YES completion:nil];
}

#import "ViewController2.h"

@interface ViewController2 ()
{
    UITextField *text2;
}
@end

@implementation ViewController2

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor blueColor];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 50)];
    label.text = @"界面二";
    [self.view addSubview:label];

    text2 = [[UITextField alloc] initWithFrame:CGRectMake(50, 150, 100, 50)];
    text2.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:text2];

    UIButton *button2 = [[UIButton alloc] initWithFrame:CGRectMake(50, 250, 100, 50)];
    [button2 addTarget:self action:@selector(returnButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [button2 setTitle:@"返回" forState:UIControlStateNormal];
    button2.backgroundColor = [UIColor blackColor];
    [self.view addSubview:button2];

    // Do any additional setup after loading the view.
}

- (void)returnButtonAction:(UIButton *)btn {
    NSDictionary *dic = @{@"returnInfo" : self->text2.text};
    NSNotification *notification = [NSNotification notificationWithName:@"chuangzhi" object:nil userInfo:dic];
    [[NSNotificationCenter defaultCenter] postNotification:notification];

    [self dismissViewControllerAnimated:NO completion:nil];
}