正向傳值 反向傳值 與 雙向傳值

效果圖

效果圖

AppDelegate.h

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (nonatomic, copy) NSString *sharedString;

@end

AppDelegate.m

#import "AppDelegate.h"
#import "TestViewControllerA.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    TestViewControllerA *vcA = [[TestViewControllerA alloc] init];
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vcA];
    self.window.rootViewController = nav;
    [self.window makeKeyAndVisible];
    
    return YES;
}

TestViewControllerA.h

#import <UIKit/UIKit.h>

@interface TestViewControllerA : UIViewController

@end

TestViewControllerA.m

#import "TestViewControllerA.h"
#import "TestViewControllerB.h"
#import "AppDelegate.h"

@interface TestViewControllerA ()<TestViewControllerBDelegate>
{
    UILabel *_delegateLabel;
    UILabel *_blockLabel;
    UILabel *_notificationLabel;
    UILabel *_mediatorLabel;
}

@end

@implementation TestViewControllerA

- (instancetype)init
{
    self = [super init];
    if (self)
    {
        [self.navigationItem setTitle:@"ViewController A"];
        
        self.edgesForExtendedLayout = UIRectEdgeNone;
    }
    return self;
}

- (void)loadView
{
    UIView *view = [[UIView alloc] init];
    view.backgroundColor = [UIColor whiteColor];
    self.view = view;
    
    //property button
    UIButton *propertyButton = [[UIButton alloc] init];
    [propertyButton setBackgroundColor:[UIColor lightGrayColor]];
    [propertyButton setTitle:@"next VC (property)" forState:UIControlStateNormal];
    [propertyButton addTarget:self action:@selector(propertyButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    propertyButton.frame = CGRectMake(50, 50, 200, 30);
    [view addSubview:propertyButton];
    
    //initializer button
    UIButton *initializerButton = [[UIButton alloc] init];
    [initializerButton setBackgroundColor:[UIColor lightGrayColor]];
    [initializerButton setTitle:@"next VC (initializer)" forState:UIControlStateNormal];
    [initializerButton addTarget:self action:@selector(initializerButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    initializerButton.frame = CGRectMake(50, CGRectGetMaxY(propertyButton.frame) + 30, 200, 30);
    [view addSubview:initializerButton];
    
    //delegate button
    UIButton *delegateButton = [[UIButton alloc] init];
    [delegateButton setBackgroundColor:[UIColor lightGrayColor]];
    [delegateButton setTitle:@"next VC (delelgate)" forState:UIControlStateNormal];
    [delegateButton addTarget:self action:@selector(delegateButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    delegateButton.frame = CGRectMake(50, CGRectGetMaxY(initializerButton.frame) + 30, 200, 30);
    [view addSubview:delegateButton];
    
    _delegateLabel = [[UILabel alloc] init];
    [_delegateLabel setBackgroundColor:[UIColor lightGrayColor]];
    [_delegateLabel setTextColor:[UIColor whiteColor]];
    [_delegateLabel setFont:[UIFont systemFontOfSize:15]];
    _delegateLabel.textAlignment = NSTextAlignmentCenter;
    _delegateLabel.frame = CGRectMake(CGRectGetMaxX(delegateButton.frame) + 5, CGRectGetMinY(delegateButton.frame), 150, 30);
    [view addSubview:_delegateLabel];
    
    //block button
    UIButton *blockButton = [[UIButton alloc] init];
    [blockButton setBackgroundColor:[UIColor lightGrayColor]];
    [blockButton setTitle:@"next VC (block)" forState:UIControlStateNormal];
    [blockButton addTarget:self action:@selector(blockButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    blockButton.frame = CGRectMake(50, CGRectGetMaxY(delegateButton.frame) + 30, 200, 30);
    [view addSubview:blockButton];
    
    _blockLabel = [[UILabel alloc] init];
    [_blockLabel setBackgroundColor:[UIColor lightGrayColor]];
    [_blockLabel setTextColor:[UIColor whiteColor]];
    [_blockLabel setFont:[UIFont systemFontOfSize:15]];
    _blockLabel.textAlignment = NSTextAlignmentCenter;
    _blockLabel.frame = CGRectMake(CGRectGetMaxX(blockButton.frame) + 5, CGRectGetMinY(blockButton.frame), 150, 30);
    [view addSubview:_blockLabel];
    
    //notification button
    UIButton *notificationButton = [[UIButton alloc] init];
    [notificationButton setBackgroundColor:[UIColor lightGrayColor]];
    [notificationButton setTitle:@"next VC (notification)" forState:UIControlStateNormal];
    [notificationButton addTarget:self action:@selector(notificationButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    notificationButton.frame = CGRectMake(50, CGRectGetMaxY(blockButton.frame) + 30, 200, 30);
    [view addSubview:notificationButton];
    
    _notificationLabel = [[UILabel alloc] init];
    [_notificationLabel setBackgroundColor:[UIColor lightGrayColor]];
    [_notificationLabel setTextColor:[UIColor whiteColor]];
    [_notificationLabel setFont:[UIFont systemFontOfSize:15]];
    _notificationLabel.textAlignment = NSTextAlignmentCenter;
    _notificationLabel.frame = CGRectMake(CGRectGetMaxX(notificationButton.frame) + 5, CGRectGetMinY(notificationButton.frame), 150, 30);
    [view addSubview:_notificationLabel];
    
    //mediator button:
    UIButton *mediatorButton = [[UIButton alloc] init];
    [mediatorButton setBackgroundColor:[UIColor lightGrayColor]];
    [mediatorButton setTitle:@"next VC (mediator)" forState:UIControlStateNormal];
    [mediatorButton addTarget:self action:@selector(mediatorButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
    mediatorButton.frame = CGRectMake(50, CGRectGetMaxY(notificationButton.frame) + 30, 200, 30);
    [view addSubview:mediatorButton];
    
    
    _mediatorLabel = [[UILabel alloc] init];
    [_mediatorLabel setBackgroundColor:[UIColor lightGrayColor]];
    [_mediatorLabel setTextColor:[UIColor whiteColor]];
    [_mediatorLabel setFont:[UIFont systemFontOfSize:15]];
    _mediatorLabel.textAlignment = NSTextAlignmentCenter;
    _mediatorLabel.frame = CGRectMake(CGRectGetMaxX(mediatorButton.frame) + 5, CGRectGetMinY(mediatorButton.frame), 150, 30);
    [view addSubview:_mediatorLabel];
    
}


#pragma mark - button
- (void)propertyButtonClicked:(id)sender
{
    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] init];
    viewControllerB.property1 = @"via Property value";
    [self.navigationController pushViewController:viewControllerB animated:YES];
}


- (void)initializerButtonClicked:(id)sender
{
    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] initWithProperty1:@"via Initializer value"];
    [self.navigationController pushViewController:viewControllerB animated:YES];
}


- (void)delegateButtonClicked:(id)sender
{
    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] init];
    viewControllerB.delegate = self;
    [self.navigationController pushViewController:viewControllerB animated:YES];
}

- (void)mediatorButtonClicked:(id)sender {
    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] initWithMediator];
    [self.navigationController pushViewController:viewControllerB animated:YES];
}


#pragma mark - block - initializer 方法
//- (void)blockButtonClicked:(id)sender {
//    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] initWithDataBlock:^(NSString *data) {
//        _blockLabel.text = data;
//    }];
//    [self.navigationController pushViewController:viewControllerB animated:YES];
//}
#pragma mark - block - 定義 @porperty 屬性方法
- (void)blockButtonClicked:(id)sender {
    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] init];
    viewControllerB.dataBlock = ^(NSString *data) {
        _blockLabel.text = data;
    };
    [self.navigationController pushViewController:viewControllerB animated:YES];
}


#pragma mark - delegate
- (void)testViewControllerB:(TestViewControllerB *)testViewControllerB sendDataBack:(NSString *)data {
    _delegateLabel.text = data;
}


#pragma mark - 點擊通知按鈕進入 控制器B 頁面的方法
- (void)notificationButtonClicked:(id)sender
{
    TestViewControllerB *viewControllerB = [[TestViewControllerB alloc] initWithNotification];
    //添加 self(viewControllerA) 為通知(TestViewControllerBNotification)這個通知的觀察者:
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notificationReceived:) name:TestViewControllerBNotification object:nil];
    [self.navigationController pushViewController:viewControllerB animated:YES];
}


#pragma mark - A界面接收到通知后的方法
/**
 接收到通知中心發給A控制器的通知之后 , A界面要做的事情!!!
 在此之前 , 界面B 已經 POST 通知到了 NSNotificationCenter 并且給通知中心帶去了一個userInfo的參數值里面放的是字典:@{@"data" : @"notification data"} .
 下面這個方法的 形參:notification 就是裝著這個字典的從B頁面傳給通知中心 , 通知中心又傳給A頁面的通知 , 這里面就裝著字典@{@"data" : @"notification data"} 
 通知里的userInfo就是我在post這個通知的時候最后帶的userInfo參數;
 */
- (void)notificationReceived:(NSNotification *)notification {
    NSDictionary *userInfo = notification.userInfo;
    if ([userInfo isKindOfClass:[NSDictionary class]])
    {
        //顯示在通知的label上:
        _notificationLabel.text = userInfo[@"data"];
    }
}


#pragma mark - viewDidAppear:
//在圖像再次顯示的時候刷新UI:
- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    if (_mediatorLabel) {
        //一旦控制器給B賦值完成 , 返回到A的時候我就拿到AppDelegate的shareString這個字符串 , 然后顯示它:
        _mediatorLabel.text = ((AppDelegate *)[UIApplication sharedApplication].delegate).sharedString;
    }
}

@end

TestViewControllerB.h

#import <UIKit/UIKit.h>
@class TestViewControllerB;

FOUNDATION_EXTERN NSString *const TestViewControllerBNotification;

typedef void(^DataBlock) (NSString * data);

@protocol TestViewControllerBDelegate <NSObject>

- (void)testViewControllerB:(TestViewControllerB *)testViewControllerB sendDataBack:(NSString *)data;

@end

@interface TestViewControllerB : UIViewController

-(instancetype)initWithProperty1:(NSString *)property1Value;

-(instancetype)initWithDataBlock:(DataBlock)dataBlock;//block也可以定義出一個initializer方法出來;
@property (nonatomic, copy) DataBlock dataBlock;//block也可以定義一個變量出來;

-(instancetype)initWithNotification;

@property (nonatomic, retain) NSString *property1;

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

- (instancetype)initWithMediator;//中間媒介 , 讓 VCA 與 VCB 相互傳值;

@end

TestViewControllerB.m

#import "TestViewControllerB.h"
#import "AppDelegate.h"

//定義通知名稱:
NSString *const TestViewControllerBNotification = @"TestViewControllerBNotification";

@interface TestViewControllerB () {
    DataBlock _dataBlock;
    BOOL _useNotification;
    BOOL _userMediator;
}

@end

@implementation TestViewControllerB

#pragma mark - init
- (instancetype)init
{
    self = [super init];
    if (self)
    {
        [self.navigationItem setTitle:@"ViewController B"];
        self.edgesForExtendedLayout = UIRectEdgeNone;
    }
    return self;
}


#pragma mark - 正向傳值initializer方法
- (instancetype)initWithProperty1:(NSString *)property1Value
{
    self = [self init];
    if (self)
    {
        self.property1 = property1Value;
    }
    return self;
}


#pragma mark - 反向傳值 block 的 initializer 方法
- (instancetype)initWithDataBlock:(DataBlock)dataBlock
{
    self = [self init];
    if (self) {
        
        _dataBlock = dataBlock;
    }
    return self;
}


- (instancetype)initWithNotification
{
    self = [self init];
    if (self) {
        _useNotification = YES;
    }
    return self;
}


- (instancetype)initWithMediator {
    self = [self init];
    if (self) {
        _userMediator = YES;
    }
    return self;
}


- (void)loadView
{
    UIView *view = [[UIView alloc] init];
    view.backgroundColor = [UIColor whiteColor];
    self.view = view;
    
    //label:正向傳值的 label;
    UILabel *label = [[UILabel alloc] init];
    [label setBackgroundColor:[UIColor lightGrayColor]];
    [label setTextColor:[UIColor whiteColor]];
    [label setFont:[UIFont systemFontOfSize:15]];
    [label setTextAlignment:NSTextAlignmentCenter];
    [label setFrame:CGRectMake(50, 50, 200, 30)];
    [view addSubview:label];
    label.text = self.property1;
    
#pragma mark - 代理 UI
    if (_delegate)
    {
        UIButton *notifyDelegateButton = [[UIButton alloc] init];
        [notifyDelegateButton setBackgroundColor:[UIColor lightGrayColor]];
        [notifyDelegateButton setTitle:@"notify delegate" forState:UIControlStateNormal];
        [notifyDelegateButton addTarget:self action:@selector(notifyDelegateButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
        notifyDelegateButton.frame = CGRectMake(50, 50, 200, 30);
        [view addSubview:notifyDelegateButton];
    }
    
#pragma mark - Block UI
    else if (_dataBlock)
    {
        UIButton *blockButton = [[UIButton alloc] init];
        [blockButton setBackgroundColor:[UIColor lightGrayColor]];
        [blockButton setTitle:@"notify block" forState:UIControlStateNormal];
        [blockButton addTarget:self action:@selector(blockButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
        blockButton.frame = CGRectMake(50, 50, 200, 30);
        [view addSubview:blockButton];

    }
    
#pragma mark - 通知 UI
    else if (_useNotification)
    {
        UIButton *notificationButton = [[UIButton alloc] init];
        [notificationButton setBackgroundColor:[UIColor lightGrayColor]];
        [notificationButton setTitle:@"notify notification" forState:UIControlStateNormal];
        [notificationButton addTarget:self action:@selector(notificationButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
        notificationButton.frame = CGRectMake(50, 50, 200, 30);
        [view addSubview:notificationButton];
    }
    
#pragma mark - Mediator UI
    else if (_userMediator) {
        UIButton *mediatorButton = [[UIButton alloc] init];
        [mediatorButton setBackgroundColor:[UIColor lightGrayColor]];
        [mediatorButton setTitle:@"notify mediator" forState:UIControlStateNormal];
        [mediatorButton addTarget:self action:@selector(mediatorButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
        mediatorButton.frame = CGRectMake(50, 50, 200, 30);
        [view addSubview:mediatorButton];
    }
}


#pragma mark - 點擊代理按鈕
- (void)notifyDelegateButtonClicked:(id)sender {
    if ([_delegate respondsToSelector:@selector(testViewControllerB:sendDataBack:)])
    {
        [_delegate testViewControllerB:self sendDataBack:@"notify delegate"];
    }
    [self.navigationController popViewControllerAnimated:YES];
}


#pragma mark - 點擊 block 按鈕
- (void)blockButtonClicked:(id)sender {
    if (_dataBlock) {
        _dataBlock(@"notify Block");
    }
    [self.navigationController popViewControllerAnimated:YES];
}


#pragma mark - 點擊 通知 按鈕
- (void)notificationButtonClicked:(id)sender {
    //所需要傳遞的值放在 userInfo 里:
    [[NSNotificationCenter defaultCenter] postNotificationName:TestViewControllerBNotification object:nil userInfo:@{@"data" : @"notification data"}];
    [self.navigationController popViewControllerAnimated:YES];
}


#pragma mark - 點擊 Mediator 按鈕
//更改AppDelegate里的sharedString:
- (void)mediatorButtonClicked:(id)sender {
    ((AppDelegate *)[UIApplication sharedApplication].delegate).sharedString = @"shared mediator";
    [self.navigationController popViewControllerAnimated:YES];   
}

@end

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