模態視圖（IOS開發） – iPhone手機開發技術文章 iPhone軟體開發教學課程

模態：模態視圖從屏幕下方滑出來，完成的時候需要關閉這個模態視圖，如果不關閉，就不能做別的事情，必須有響應處理的含義。

主視圖控制器－－－》模態視圖控制器。主視圖控制器與模態視圖控制器之間為父子關系。

UIViewController類中，主要有以下兩個方法：

presentViewController:animated:completion 呈現模態視圖

dismissViewControllerAnimated:completion 關閉模態視圖

代碼：

ViewController.h

#import 

@interface ViewController : UIViewController

- (IBAction)regonclick:(id)sender;

@end

ViewController.m

#import "ViewController.h"
#import "RegisterViewController.h"

@interface ViewController ()


@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // 如果要傳遞參數的時候，應該用委托設計模式或者廣播通知機制
    // 這裡為廣播通知機制
    // 註冊一個自定義通知RegisterCompletionNotification，通知到來時候發出registerCompletion:消息，其參數notification中可以包含回傳的參數,統一放在NSDictionary字典中
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(registerCompletion:) name:@"RegisterCompletionNotification" object:nil];
    
}
- (void)registerCompletion:(NSNotification *)notification
{
    // 獲取參數userInfo,是一個字典
    NSDictionary *theData = [notification userInfo];
    // 獲取字典的username索引值
    NSString *username = [theData objectForKey:@"username"];
    
    NSLog(@"username = %@", username);
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)regonclick:(id)sender {
    // 使用registerViewController的ID獲取視圖控制器對象
    UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    UIViewController *registerViewController = [mainStoryboard instantiateViewControllerWithIdentifier:@"registerViewController"];
    
    // 設定模態視圖呈現和關閉時候的動畫效果
    // 垂直方向由底向上退出
    registerViewController.modalPresentationStyle = UIModalTransitionStyleCoverVertical;
    
    // 呈現完成時調用completion代碼塊
    // 代碼塊問題回頭再說
    [self presentViewController:registerViewController animated:YES completion:^{
        NSLog(@"Present Modal View");
    }];
}
@end

ResgisterViewController.h

#import 

@interface RegisterViewController : UIViewController

- (IBAction)done:(id)sender;
@property (weak, nonatomic) IBOutlet UITextField *txtUsername;

@end

ResgisterViewController.m

#import "RegisterViewController.h"

@interface RegisterViewController ()

@end

@implementation RegisterViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

- (IBAction)done:(id)sender {
    // 關閉模態視圖，然後繼續調用代碼塊
    [self dismissViewControllerAnimated:YES completion:^{
        // 代碼塊
        NSLog(@"Modal View done");
        
        // 創建一個以username為索引的字典對象
        NSDictionary *dataDict = [NSDictionary dictionaryWithObject:self.txtUsername.text forKey:@"username"];
        [[NSNotificationCenter defaultCenter] postNotificationName:@"RegisterCompletionNotification" object:nil
         userInfo:dataDict]; 
    }];
    
    

}
@end