GCD_Grand central dispatch 解决资源抢夺问题(买车票) shareSDK

／／GCD_Grand central dispatch

//
//  ViewController.m
//  GCD_Grand central dispatch
//
//  Created by DC020 on 15/12/25.
//  Copyright (c) 2015年 Bill. All rights reserved.
//

#import "ViewController.h"
#define ROW 3
#define CONLUMN 5
#define imageCount WINTH * CONLUNM

@interface ViewController (){
    NSMutableArray *_MutableArray;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    _MutableArray = [NSMutableArray array];
    for (int c = 0; c < CONLUMN; c++) {
        for (int r = 0; r < ROW; r++) {
            UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(18.75+r*118.75, 70+c*118.75, 100, 100)];
            imageView.backgroundColor = [UIColor redColor];
            [self.view addSubview:imageView];
            [_MutableArray addObject:imageView];
        }
    }
    UIButton *button  = [[UIButton alloc]initWithFrame:CGRectMake(50, 40, 275, 20)];

    [button addTarget:self action:@selector(GCDdemoRun) forControlEvents:UIControlEventTouchUpInside];
    [button setTitle:@"加载图片" forState:UIControlStateNormal];
    [button setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    [self.view addSubview:button];

}
-(void)loadImage:(int)Index{
        //打印当前线程
    NSLog(@"%@",[NSThread currentThread]);
    //获取图片数据
    NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString: [NSString stringWithFormat:@"http://b.zol-img.com.cn/desk/bizhi/image/7/2560x1600/1447404575613.jpg"]]];
    //获取主队列，更新UI
    dispatch_queue_t mainQueue = dispatch_get_main_queue();
    //同步执行
    //当前线程正在执行任务时，不会开启新线程
    dispatch_sync(mainQueue, ^{
        UIImage *image = [UIImage imageWithData:data];
        UIImageView *imageView = _MutableArray[Index];
        imageView.image = image;
    });
}

-(void)GCDdemoRun{
    //队列组
    dispatch_group_t groupQueue = dispatch_group_create();
    //组1开始异步执行
    dispatch_group_async(groupQueue, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSLog(@"组1任务完成");
    });
    //组2开始异步执行
    dispatch_group_async(groupQueue, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSLog(@"组2任务完成");
    });
    //监听组队列任务完成
    dispatch_group_notify(groupQueue, dispatch_get_main_queue(), ^{
        NSLog(@"组队列任务结束");
    });

}
//锁🔒机制
//IOS中经常使用两种方法
//1.NSLock
//2.@synchronized


//-(void)GCDdemoRun{
//    //全局队列（可开启多个线程）
//    //参数:优先级（high，default，low）
//    //参数2:标记参数，目前没有用，通常写0
//    dispatch_queue_t  globalQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
//    //建立线程执行任务
//    for (int i = 0; i < 15; i++) {
//        //异步执行队列任务
//        dispatch_async(globalQueue, ^{
//            [self loadImage:i];
//        });
//    }
//}


//-(void)GCDdemoRun{
//    //串行队列
//    //参数：队列名称，队列类型
//    dispatch_queue_t serialQueue = dispatch_queue_create("mySerialQueue", DISPATCH_QUEUE_SERIAL);
//    //建立1个线程(执行15个任务)
//    for(int i = 0; i < 15;i++){
//        //异步执行队列任务
//        //因为是串行队列，因此不会开启新的线程
//        dispatch_async(serialQueue, ^{
//            [self loadImage:i];
////            sleep(1);//休眠一秒
//        });
//    }
//}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

／／shareSDK

关键要用button添加事件；

／／  解决资源抢夺问题(买车票)

  //
//  ViewController.m
//  解决资源抢夺问题(买车票)
//
//  Created by DC020 on 15/12/25.
//  Copyright (c) 2015年 Bill. All rights reserved.
//

#import "ViewController.h"

@interface ViewController (){
    NSLock *_lock;
}

//nonatomic属性读取的是内存数据（寄存器计算好的结果）
//atomic属性保持直接读取寄存器的数据，****［这样就不会出现一个线程正在修改数据，而另外一个线程读取了修改以前的数据］****永远保证同时只有一个线程在访问一个属性
@property(atomic,strong)NSMutableArray *tickets;//票
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    _lock =[[NSLock alloc]init];
    _tickets = [NSMutableArray array];
    [_tickets addObjectsFromArray:@[@"1.上铺",@"2.中铺",@"3.下铺"]];
    [self beginSell];
}


-(void)buyTicket:(int)buyer{
    NSLog(@"%d",buyer);//10位顾客准备购买
    //使用时，把须要加锁的代码放在lock和unlock之间。
    //当一个线程A进入加锁代码后，另外一个线程B他就没法访问，只有当线程A执行完加锁的任务之后，B线程才能访问加锁代码
//    [_lock lock];//上锁
    @synchronized(self){
    if(_tickets.count > 0){
        NSLog(@"%d号顾客买到:%@",buyer,[_tickets lastObject]);
        [_tickets removeLastObject];
    }
    else{
        NSLog(@"%d号顾客晚了一步，票已卖完了！！！",buyer);
    }
    }
//    [_lock unlock];//解锁
}

-(void)beginSell{
    dispatch_queue_t globalQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    //建立10个线程用来抢票（10我的来买票）
    for(int i = 0; i < 10 ; i++){
        //异步执行
        dispatch_async(globalQueue, ^{
            [self buyTicket:i];
        });
    }
}


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

@end