UI基础 单例传值 Block 通知

app.m

#import "AppDelegate.h"
#import "RootViewController.h"
@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    
    
    RootViewController* root=[[RootViewController alloc]init];
    UINavigationController *nav =[[UINavigationController alloc]initWithRootViewController:root];
    self.window.rootViewController=nav;
    
    nav.navigationBar.barTintColor=[UIColor greenColor];
    nav.navigationBar.translucent=NO;
    
    
    
    
    return YES;
}

root.h

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface RootViewController : UIViewController

@end

NS_ASSUME_NONNULL_END

root.m

#import "RootViewController.h"
#import "SecondViewController.h"
#import "MyData.h"
@interface RootViewController ()

@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor=[UIColor yellowColor];
    
    // 跳转
    self.navigationItem.leftBarButtonItem=[[UIBarButtonItem alloc] initWithTitle:@"跳转" style:UIBarButtonItemStylePlain target:self action:@selector(jumpToNext)];
    
    //创建一个单例对象并赋值
    MyData* data =[MyData instance];
    data.name=@"赵日天";
    
    //通知
    //注册通知 （好比打开收音机 调节对应频率）
    //只要调节收音机 就能收到这些广播
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveMessage:) name:@"99.7" object:nil];
    
    
}
//收到通知执行的方法 ，参数就是接收到的通知
-(void)receiveMessage:(NSNotification *)not
{
    NSLog(@"%@",not.object);
    
}

//视图要消失
-(void)viewWillDisappear:(BOOL)animated
{
    //移除通知 （将收音机关闭）
    [[NSNotificationCenter defaultCenter]removeObserver:self name:@"99.7" object:nil];
    
}


-(void)jumpToNext
{
    SecondViewController *second =[[SecondViewController alloc]init];
    
    __block RootViewController *tempself=self;
    second.chuanzhiBlock=^(NSString *str){
        NSLog(@"%@",str);
        tempself.navigationItem.title=@"11111";
        
        
        
    };
    
    [self.navigationController pushViewController:second animated:YES];
    
}


@end

second.h

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface SecondViewController : UIViewController

@property(nonatomic,copy)void(^chuanzhiBlock)(NSString *str);



@end

NS_ASSUME_NONNULL_END

second.m

#import "SecondViewController.h"
#import "MyData.h"
@interface SecondViewController ()

@end

@implementation SecondViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.view.backgroundColor=[UIColor orangeColor];
    
    // 跳转
    self.navigationItem.leftBarButtonItem=[[UIBarButtonItem alloc] initWithTitle:@"返回" style:UIBarButtonItemStylePlain target:self action:@selector(jumpBack)];
    
    MyData *data=[MyData instance];
    NSLog(@"%@",data.name);
    
    
    //创建一个对象 并赋值
}

-(void)jumpBack
{
    self.chuanzhiBlock(@"block将王尼玛传回去");
    
    //发送广播 （通知）
    [[NSNotificationCenter defaultCenter]postNotificationName:@"99.7" object:@"通知传值"];
    
    [self.navigationController popToRootViewControllerAnimated:YES];

    
    
}

@end

MyData.h

#import <Foundation/Foundation.h>



@interface MyData : NSObject

@property(nonatomic,strong)NSString* name;
+(MyData *)instance;

@end

MyData.m

#import "MyData.h"

@implementation MyData

static MyData *myData =nil;
+(MyData *)instance
{
    if (myData ==nil){
        myData =[[MyData alloc] init];
        
    }
    return myData;
    
    
}
@end