IOS四種反向傳值的方法

方法一:使用target-action設計模式

代碼如下:(由根視圖推出子視圖,再由子視圖推出根視圖,在推出根視圖時,子視圖傳一個color的屬性給根視圖,用來修改根視圖的背景顏色)

根視圖控制器代碼：

//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor redColor];

    [self createButton];
}

- (void)createButton
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入下一個視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];
}

- (void)btnClick
{
    Sub1ViewController * sub1 = [[Sub1ViewController alloc]init];

    sub1.view.backgroundColor = [UIColor blueColor];

    sub1.target = self;

    sub1.action = @selector(changeColor:);

    [self presentViewController:sub1 animated:YES completion:nil];
}

- (void)changeColor:(UIColor *)color
{
    self.view.backgroundColor = color;
}

子視圖控制器代碼：

//.h文件

@interface Sub1ViewController : UIViewController
@property (assign,readwrite,nonatomic)id target;
@property (assign,readwrite,nonatomic)SEL action;
@end

//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    [self createPopToRootViewBtn];
}

- (void)createPopToRootViewBtn
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入根視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];
}

- (void)btnClick
{
    if ([_target respondsToSelector:_action])
    {
        [_target performSelector:_action withObject:[UIColor orangeColor]];
    }
    [self dismissViewControllerAnimated:YES completion:nil];
}

方法二:通知

根視圖控制器代碼：

//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor redColor];

    [self createButton];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(changeColor:) name:@"ChangeColor" object:nil];
}

- (void)createButton
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入下一個視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];
}

- (void)btnClick
{
    Sub1ViewController * sub1 = [[Sub1ViewController alloc]init];

    sub1.view.backgroundColor = [UIColor blueColor];

    [self presentViewController:sub1 animated:YES completion:nil];
}

- (void)changeColor:(NSNotification *)nofi
{
    self.view.backgroundColor = [nofi.userInfo objectForKey:@"color"];
}

子視圖控制器代碼：

//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    [self createPopToRootViewBtn];
}

- (void)createPopToRootViewBtn
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入根視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

    [[NSNotificationCenter defaultCenter]postNotificationName:@"ChangeColor" object:self userInfo:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor orangeColor],@"color", nil]];

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

    [self.view addSubview:btn]; 
}

- (void)btnClick
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

方法三:代碼塊

根視圖控制器代碼:

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor redColor];

    [self createButton];
}

- (void)createButton
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入下一個視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];
}

- (void)btnClick
{
    Sub1ViewController * sub1 = [[Sub1ViewController alloc]init];

    sub1.view.backgroundColor = [UIColor blueColor];

    sub1.MyBlock = ^(UIColor * color)
    {
        self.view.backgroundColor = color;
    };

    [self presentViewController:sub1 animated:YES completion:nil];
}

子視圖控制器代碼：

//.h文件
@interface Sub1ViewController : UIViewController
@property (copy,nonatomic,readwrite)void (^MyBlock)(UIColor * color);
@end
//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    [self createPopToRootViewBtn];
}

- (void)createPopToRootViewBtn
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入根視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];


}

- (void)btnClick
{
    _MyBlock([UIColor orangeColor]);
    [self dismissViewControllerAnimated:YES completion:nil];
}

方法四:代理-協議

根視圖控制器代碼：

//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor redColor];

    [self createButton];
}

- (void)createButton
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入下一個視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];
}

- (void)btnClick
{
    Sub1ViewController * sub1 = [[Sub1ViewController alloc]init];

    sub1.view.backgroundColor = [UIColor blueColor];
    sub1.delegate = self;
    [self presentViewController:sub1 animated:YES completion:nil];
}

- (void)changeColor:(UIColor *)color
{
    self.view.backgroundColor = color;
}

子視圖控制器代碼：

//.h文件 
@protocol Sub1ViewControllerDelete <NSObject>
- (void)changeColor:(UIColor *)color;
@end

@interface Sub1ViewController : UIViewController
@property (assign,nonatomic,readwrite)id <Sub1ViewControllerDelete>delegate;
@end
//.m文件
- (void)viewDidLoad
{
    [super viewDidLoad];

    [self createPopToRootViewBtn];
}

- (void)createPopToRootViewBtn
{
    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame = CGRectMake(10, 30, 300, 40);
    [btn setTitle:@"進入根視圖控制器" forState:UIControlStateNormal];
    btn.layer.cornerRadius = 5;

    btn.backgroundColor = [UIColor blackColor];

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

    [self.view addSubview:btn];


}

- (void)btnClick
{
    [_delegate changeColor:[UIColor orangeColor]];

    [self dismissViewControllerAnimated:YES completion:nil];
}