GCD--队列的类型和执行任务方式的四种的排列组合

串行队列

  • 串行队列同步执行
- (IBAction)SerialQueueSync:(id)sender {
    //1.创建串行队列
    dispatch_queue_t queue = dispatch_queue_create("FirstSerialQueue", DISPATCH_QUEUE_SERIAL);
    //2.提交任务到队列中(block)
    //同步执行任务
    dispatch_sync(queue, ^{
        //任务逻辑
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"++++++++++%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第一个打印完毕");
    //第二个任务
    dispatch_sync(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"----------%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第二个打印完毕");
}

GCD--队列的类型和执行任务方式的四种的排列组合_第1张图片


  • 串行队列异步执行
- (IBAction)SerialQueueAsync:(id)sender {
    dispatch_queue_t queue = dispatch_queue_create("SecondSerialQueue", DISPATCH_QUEUE_SERIAL);
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"++++++++++%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第一个打印完毕");
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"----------%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第二个打印完毕");
}

GCD--队列的类型和执行任务方式的四种的排列组合_第2张图片


并行队列

  • 并行队列同步执行
//几乎不用这种组合(串行队列+同步执行结果一样)
- (IBAction)concurrentQueueSync:(id)sender {
    dispatch_queue_t queue = dispatch_queue_create("FirstConcurrentQueue", DISPATCH_QUEUE_CONCURRENT);
    dispatch_sync(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"++++++++++%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第一个打印完毕");
    dispatch_sync(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"----------%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第二个打印完毕");
}

GCD--队列的类型和执行任务方式的四种的排列组合_第3张图片


  • 并行队列异步执行
- (IBAction)concurrentQueuAsync:(id)sender {
    dispatch_queue_t queue = dispatch_queue_create("SecondConcurrentQueue", DISPATCH_QUEUE_CONCURRENT);
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"++++++++++%@", [NSThread currentThread]);
        }
    });

    NSLog(@"第一个打印完毕");
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"----------%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第二个打印完毕");
}

GCD--队列的类型和执行任务方式的四种的排列组合_第4张图片


全局队列

  • 全局队列异步执行
//和并行队列异步执行一模一样
- (IBAction)globalQueueAsync:(id)sender {
    //获取系统默认创建的全局队列(参数一:给定队列的优先级)
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    //提交任务到全局队列中
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"++++++++++++:%@",[NSThread currentThread]);
        }
    });
    NSLog(@"第一个打印完毕");
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"----------%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第二个打印完毕");
}

GCD--队列的类型和执行任务方式的四种的排列组合_第5张图片


主队列

  • 主队列异步执行
- (IBAction)mainQueueAsync:(id)sender {
    //注意:所有主队列中的任务都是由主线程完成
    //获取系统默认创建好的主队列
    dispatch_queue_t queue = dispatch_get_main_queue();
    //提交任务到主队列中
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"++++++++++%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第一个打印完毕");
    dispatch_async(queue, ^{
        for (int i = 0; i < 10; i++) {
            [NSThread sleepForTimeInterval:1];
            NSLog(@"----------%@", [NSThread currentThread]);
        }
    });
    NSLog(@"第二个打印完毕");
}

GCD--队列的类型和执行任务方式的四种的排列组合_第6张图片


  • 主队列同步执行
//死锁问题(任务不要放到主队列中并且同步执行)
- (IBAction)mainQueueSync:(id)sender {
    //主队列同步执行
    NSLog(@"任务一");
    dispatch_sync(dispatch_get_main_queue(), ^{
        NSLog(@"任务二");
    });
    NSLog(@"任务三");


}

主队列同步执行打印结果

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