iOS - 多线程

作者: Bruce_XHG | 来源:发表于2017-04-27 20:56 被阅读0次

多线程在开发过程中的应用。有些业务逻辑的需要,需要我们使用到多线程。今天就常用的业务模式进行一下简单的说明。

  • 串行队列同步执行;

  • 串行队列异步执行;

  • 并行队列同步执行;

  • 并行队列异步执行;

  • 主队列异步执行;

  • 主队列同步执行;

  • 子线程下载主线程刷新;

  • 队列组的使用;

  • Thread;

  • operation;

  • 1、串行队列同步执行

串行队列同步执行 (在当前线程中顺序执行) 用于前后有依赖关系的处理 用的都是一条线程(在主线程中),不会开辟新线程。注意在主线程中耗时操作会造成主线程阻塞#

dispatch_queue_t serialQueue = dispatch_queue_create("serialQueue", DISPATCH_QUEUE_SERIAL);//创建串行队列
    dispatch_sync(serialQueue, ^{
        DebugLog(@"串行队列同步执行- 1 == %@",[NSThread currentThread]);
    });
    dispatch_sync(serialQueue, ^{
        DebugLog(@"串行队列同步执行- 2 == %@",[NSThread currentThread]);
    });
    dispatch_sync(serialQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"串行队列同步执行- 3 == %@",[NSThread currentThread]);
        }
    });
    //串行队列同步执行完以后走下面的代码(回到主线程)
    [SVProgressHUD showInfoWithStatus:@"串行队列同步执行执行完毕"];
    DebugLog(@"串行队列同步执行执行完毕 == %@",[NSThread currentThread]);

看一下执行顺序##

GCDLearnViewController.m:102    
串行队列同步执行- 1 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:105    
串行队列同步执行- 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:110    
串行队列同步执行- 3 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:110    
串行队列同步执行- 3 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:110    
串行队列同步执行- 3 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:115    
串行队列同步执行执行完毕 == <NSThread: 0x61800006fe40>{number = 1, name = main}
  • 2、串行队列异步执行

串行队列异步执行 (在当前线程中顺序执行) 用于前后有依赖关系的处理 用的都是一条线程(在子线程中),耗时操作和有依赖关系的处理,可以用此方法#

dispatch_queue_t serialQueue = dispatch_queue_create("serialQueue", DISPATCH_QUEUE_SERIAL);
    dispatch_async(serialQueue, ^{
        DebugLog(@"串行队列异步执行 - 1 == %@",[NSThread currentThread]);
    });
    dispatch_async(serialQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"串行队列异步执行 - 2 == %@",[NSThread currentThread]);
        }
    });
    dispatch_async(serialQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"串行队列异步执行 - 3 == %@",[NSThread currentThread]);
        }
        
        dispatch_async(dispatch_get_main_queue(), ^{//串行队列异步执行执行完毕 回到主线程
            [SVProgressHUD showInfoWithStatus:@"串行队列异步执行执行完毕"];
            DebugLog(@"串行队列异步执行执行完毕 == %@",[NSThread currentThread]);
        });
    });

看一下执行顺序##

GCDLearnViewController.m:122    
串行队列异步执行 - 1 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:127    
串行队列异步执行 - 2 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:127    
串行队列异步执行 - 2 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:127    
串行队列异步执行 - 2 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:133    
串行队列异步执行 - 3 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:133    
串行队列异步执行 - 3 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:133    
串行队列异步执行 - 3 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:138    
串行队列异步执行执行完毕 == <NSThread: 0x61800006fe40>{number = 1, name = main}
  • 3、并行队列同步执行

并行队列同步执行 (number = 1, name = main) 在主线程中顺序执行;

dispatch_queue_t ConcurrentQueue = dispatch_queue_create("Concurrent", DISPATCH_QUEUE_CONCURRENT);
    dispatch_sync(ConcurrentQueue, ^{
        DebugLog(@"并行队列同步执行 - 1 == %@",[NSThread currentThread]);
    });
    dispatch_sync(ConcurrentQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"并行队列同步执行 - 2 == %@",[NSThread currentThread]);
        }
    });
    dispatch_sync(ConcurrentQueue, ^{
        DebugLog(@"并行队列同步执行 - 3 == %@",[NSThread currentThread]);
    });

看一下执行顺序##

GCDLearnViewController.m:147    
并行队列同步执行 - 1 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:152    
并行队列同步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:152    
并行队列同步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:152    
并行队列同步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:156    
并行队列同步执行 - 3 == <NSThread: 0x61800006fe40>{number = 1, name = main}
  • 4、并行队列异步执行

并行队列异步执行 开辟新线程 无序执行#

    dispatch_queue_t ConcurrentQueue = dispatch_queue_create("Concurrent", DISPATCH_QUEUE_CONCURRENT);
    dispatch_async(ConcurrentQueue, ^{
        DebugLog(@"并行队列异步执行 - 1 == %@",[NSThread currentThread]);
    });
    dispatch_async(ConcurrentQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"并行队列异步执行 - 2 == %@",[NSThread currentThread]);
        }
    });
    dispatch_async(ConcurrentQueue, ^{
        DebugLog(@"并行队列异步执行 - 3 == %@",[NSThread currentThread]);
    });

看一下执行顺序##

GCDLearnViewController.m:164    
并行队列异步执行 - 1 == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:169    
并行队列异步执行 - 2 == <NSThread: 0x61800007bc40>{number = 6, name = (null)}
GCDLearnViewController.m:173    
并行队列异步执行 - 3 == <NSThread: 0x608000076440>{number = 7, name = (null)}
GCDLearnViewController.m:169    
并行队列异步执行 - 2 == <NSThread: 0x61800007bc40>{number = 6, name = (null)}
GCDLearnViewController.m:169    
并行队列异步执行 - 2 == <NSThread: 0x61800007bc40>{number = 6, name = (null)}
  • 5、主队列异步执行

主队列异步执行 ({number = 1, name = main}) 在主线程中顺序执行#

dispatch_queue_t mainQueue = dispatch_get_main_queue();
    dispatch_async(mainQueue, ^{
        DebugLog(@"主队列异步执行 - 1 == %@",[NSThread currentThread]);
    });
    dispatch_async(mainQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"主队列异步执行 - 2 == %@",[NSThread currentThread]);
        }
    });
    dispatch_async(mainQueue, ^{
        DebugLog(@"主队列异步执行 - 3 == %@",[NSThread currentThread]);
    });

看一下执行顺序##

GCDLearnViewController.m:181    
主队列异步执行 - 1 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:186    
主队列异步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:186    
主队列异步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:186    
主队列异步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:190    
主队列异步执行 - 3 == <NSThread: 0x61800006fe40>{number = 1, name = main}
  • 6、主队列同步执行

主队列同步执行 会造成主线程卡死#

dispatch_queue_t mainQueue = dispatch_get_main_queue();
    dispatch_async(mainQueue, ^{
        DebugLog(@"主队列同步执行 - 1 == %@",[NSThread currentThread]);
    });
    dispatch_async(mainQueue, ^{
        for (int i = 0; i < 3; i++) {
            
            DebugLog(@"主队列同步执行 - 2 == %@",[NSThread currentThread]);
        }
    });
    dispatch_async(mainQueue, ^{
        DebugLog(@"主队列同步执行 - 3 == %@",[NSThread currentThread]);
    });

看一下执行顺序##

GCDLearnViewController.m:199    
主队列同步执行 - 1 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:204    
主队列同步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:204    
主队列同步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:204    
主队列同步执行 - 2 == <NSThread: 0x61800006fe40>{number = 1, name = main}
GCDLearnViewController.m:208    
主队列同步执行 - 3 == <NSThread: 0x61800006fe40>{number = 1, name = main}
  • 7、子线程下载主线程刷新
dispatch_async(dispatch_get_global_queue(0, 0), ^{
        for (int i = 0; i < 3; i++) {
            DebugLog(@"下载操作");
        }
        dispatch_async(dispatch_get_main_queue(), ^{//这个也是子线程和主线程间的一种通信
            [SVProgressHUD showInfoWithStatus:@"下载完成,刷新主线程"];
            DebugLog(@"下载完成,刷新主线程");
        });
    });

看一下执行顺序##

GCDLearnViewController.m:216    
下载操作
GCDLearnViewController.m:216    
下载操作
GCDLearnViewController.m:216    
下载操作
GCDLearnViewController.m:220    
下载完成,刷新主线程
  • 8、队列组的使用

全部处理结束后刷新主线程#

dispatch_group_t group = dispatch_group_create();//队列组
    dispatch_queue_t queue = dispatch_get_global_queue(0, 0);//全局并发队列
    dispatch_group_async(group, queue, ^{//异步操作1
        for (int i = 0; i < 3; i ++) {
            DebugLog(@"异步操作1");
        }
    });
    dispatch_group_async(group, queue, ^{//异步操作2
        for (int i = 0; i < 3; i ++) {
            DebugLog(@"异步操作2");
        }
    });
    dispatch_group_async(group, queue, ^{//异步操作3
        for (int i = 0; i < 3; i ++) {
            DebugLog(@"异步操作3");
        }
    });
    dispatch_group_notify(group, dispatch_get_main_queue(), ^{//全部处理结束后刷新主线程
        [SVProgressHUD showInfoWithStatus:@"异步操作完成,回到主线程"];
        DebugLog(@"异步操作完成,回到主线程");
    });

看一下执行顺序##

GCDLearnViewController.m:231    
异步操作1
GCDLearnViewController.m:231    
异步操作1
GCDLearnViewController.m:231    
异步操作1
GCDLearnViewController.m:236    
异步操作2
GCDLearnViewController.m:241    
异步操作3
GCDLearnViewController.m:236    
异步操作2
GCDLearnViewController.m:241    
异步操作3
GCDLearnViewController.m:236    
异步操作2
GCDLearnViewController.m:241    
异步操作3
GCDLearnViewController.m:246    
异步操作完成,回到主线程
  • 9、Thread
NSThread *thread01 = [[NSThread alloc] initWithTarget:self selector:@selector(thread1) object:nil];
    thread01.name = @"北京售票窗口";
    [thread01 start];//需要启动
    NSThread *thread02 = [[NSThread alloc] initWithTarget:self selector:@selector(thread1) object:nil];
    thread02.name = @"广州售票窗口";
    [thread02 start];//需要启动
while (1) {
        @synchronized (self) {//加锁,防止资源争夺出现问题
            if (ticketCont > 0) {
                ticketCont--;
                DebugLog(@"%@",[NSString stringWithFormat:@"剩余票数:%d 窗口:%@", ticketCont, [NSThread currentThread].name]);
                [NSThread sleepForTimeInterval:.2f];
            }
            else{
                if ([[NSThread currentThread] isCancelled]) {
                    break;
                }
                else{
                    DebugLog(@"票卖完了 %@",[NSThread currentThread]);
                    [[NSThread currentThread] cancel];
                }
            }
        }
    }

看一下打印##

GCDLearnViewController.m:325    
剩余票数:9 窗口:北京售票窗口
GCDLearnViewController.m:325    
剩余票数:8 窗口:广州售票窗口
GCDLearnViewController.m:325    
剩余票数:7 窗口:北京售票窗口
GCDLearnViewController.m:325    
剩余票数:6 窗口:广州售票窗口
GCDLearnViewController.m:325    
剩余票数:5 窗口:北京售票窗口
GCDLearnViewController.m:325    
剩余票数:4 窗口:广州售票窗口
GCDLearnViewController.m:325    
剩余票数:3 窗口:北京售票窗口
GCDLearnViewController.m:325    
剩余票数:2 窗口:广州售票窗口
GCDLearnViewController.m:325    
剩余票数:1 窗口:北京售票窗口
GCDLearnViewController.m:325    
剩余票数:0 窗口:广州售票窗口
GCDLearnViewController.m:333    
票卖完了 <NSThread: 0x60000007e640>{number = 8, name = 北京售票窗口}
GCDLearnViewController.m:333    
票卖完了 <NSThread: 0x610000269cc0>{number = 9, name = 广州售票窗口}
  • 10、Operation
NSInvocationOperation *op1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(operation1:) object:nil];
    op1.name = @"北京售票窗口";
    
    NSInvocationOperation *op2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(operation1:) object:nil];
    op2.name = @"广州售票窗口";
    
    //如果不添加到NSOperationQueue里面就不会开启线程,会在当前线程中执行
    operationQueue = [[NSOperationQueue alloc] init];//默认是并发的,如果想实现串行, 那么就设置队列的maxConcurrentOperationCount = 1
    [operationQueue addOperation:op1];
    [operationQueue addOperation:op2];
while (1) {
        @synchronized (self) {//加锁,防止资源争夺出现问题
            if (ticketCont > 0) {
                ticketCont--;
                DebugLog(@"%@",[NSString stringWithFormat:@"剩余票数:%d 窗口:%@ == %@", ticketCont, op.name,[NSThread currentThread]]);
            }
            else{
                DebugLog(@"票卖完了 %@",[NSThread currentThread]);
                break;
            }
        }
    }

看一下打印##

GCDLearnViewController.m:352    
剩余票数:9 窗口:(null) == <NSThread: 0x61800007ea00>{number = 11, name = (null)}
GCDLearnViewController.m:352    
剩余票数:8 窗口:(null) == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:352    
剩余票数:7 窗口:(null) == <NSThread: 0x61800007ea00>{number = 11, name = (null)}
GCDLearnViewController.m:352    
剩余票数:6 窗口:(null) == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:352    
剩余票数:5 窗口:(null) == <NSThread: 0x61800007ea00>{number = 11, name = (null)}
GCDLearnViewController.m:352    
剩余票数:4 窗口:(null) == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:352    
剩余票数:3 窗口:(null) == <NSThread: 0x61800007ea00>{number = 11, name = (null)}
GCDLearnViewController.m:352    
剩余票数:2 窗口:(null) == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:352    
剩余票数:1 窗口:(null) == <NSThread: 0x61800007ea00>{number = 11, name = (null)}
GCDLearnViewController.m:352    
剩余票数:0 窗口:(null) == <NSThread: 0x6180000755c0>{number = 5, name = (null)}
GCDLearnViewController.m:355    
票卖完了 <NSThread: 0x61800007ea00>{number = 11, name = (null)}
GCDLearnViewController.m:355    
票卖完了 <NSThread: 0x6180000755c0>{number = 5, name = (null)}

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