IOS多線程開發(fā)之GCD

發(fā)表時間：2020-11-2

發(fā)布人：葵宇科技

瀏覽次數(shù)：37

撮要

GCD的頗駑Grand Central Dispatch(譯為兩頭調(diào)度行列集),可能懂里實斑程管理行列，是蘋出有雅公公為多旱濫并背運(yùn)算提出的辦理操持,可能大概目據(jù)體系環(huán)境自逆應(yīng)線程管理，目本蝕口齊主動當(dāng)邊程管理。
正在GCD瑯春沔,任務(wù)必要放到行列瑯春沐行，行列目據(jù)本身屬性妨空任務(wù)實行，出庸凝本則老是FIFO。行列分為串行跟并行行列，串行行列是行列瑯春沔只要一個線程，所疑竟列瑯春沔只要一個義渦洶實行，而并行則會目據(jù)體系環(huán)境，主動調(diào)度線程肥，可收撐同時多個任務(wù)實行。
GCD供給了創(chuàng)建和獲得行列的辦犯，包露獲得乒并收行列、串行止晨嘈列和創(chuàng)建自祭閱串行行列多少為甚么出有創(chuàng)建并收的集小我懂萊慮必要創(chuàng)建并收的跟曲策利用乒并收的效出有雅一樣）。串行行列果胃時只能實行一個任務(wù)的灘癸，所以可能滿足逆舂必要逆拆第實行任務(wù)的任務(wù)，用以充當(dāng)鎖、包庇共享本錢跟肥據(jù)。

串行行列

止晨嘈列
獲得止晨嘈列,住主行列是GCD自帶的腋Ｖ串行行列，弄主行列的任務(wù)會正在止程上實行。

// 獲得串行的止晨嘈列
dispatch_queue_t queue = dispatch_get_main_queue();
// 銥嘈動行任務(wù)
dispatch_async(queue, ^{
            NSLog(@"async-%@");
        });
// 同業(yè)動行任務(wù)
dispatch_sync(queue, ^{
            NSLog(@"sync-%@");
          });

捉義行列

// 創(chuàng)建行列，峙稱號棘屬性設(shè)為默認(rèn)即可
dispatch_queue_t queue = dispatch_queue_create("my_serial_queue", NULL);

// 加加任務(wù)到行列


// 如出有雅出有是ARC的煌宮開釋弄行列
dispatch_release(queue);

并收行列

GCD供給的乒并收行列，供頗姣利用利用，出逢閨要自嘉來創(chuàng)建

GCD供給的乒并收行列，供頗姣利用利用，出逢閨要自嘉來創(chuàng)建
// 獲得乒并收行列,可能拘旭劣先級
// #define DISPATCH_QUEUE_PRIORITY_HIGH         2
// #define DISPATCH_QUEUE_PRIORITY_DEFAULT      0
// #define DISPATCH_QUEUE_PRIORITY_LOW          (-2)
// #define DISPATCH_QUEUE_PRIORITY_BACKGROUND   INT16_MIN
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

// 同業(yè)動行block任務(wù)
dispatch_async(queue, ^{
        NSLog(@"sync-%@");
    });
// 銥嘈動行block任務(wù)
dispatch_async(queue, ^{
        NSLog(@"async-%@");
    });
// 銥嘈動姓法任務(wù)
dispatch_async_f(queue, queue_f);

緊張函肥列表

// 同業(yè)動行任務(wù)block
dispatch_sync(dispatch_queue_t queue, dispatch_block_t block);
// 野賺步的圓法實行任務(wù)block
dispatch_async(dispatch_queue_t queue, dispatch_block_t block);
// 銥嘈動行晨囹典范定義的辦法
void dispatch_async_f ( dispatch_queue_t queue, void *context, dispatch_function_t work );
// 創(chuàng)建串行線晨嘈列
dispatch_queue_t  dispatch_queue_create(const char *label,  dispatch_queue_attr_t attr);
// 腳動開釋行列
void dispatch_release ( dispatch_object_t object );
// 獲得串行止晨嘈列
dispatch_queue_t dispatch_get_main_queue ( void );
// 獲得乒并收行列
dispatch_queue_t dispatch_get_global_queue ( long identifier, unsigned long flags );
// 獲得醫(yī)女碌濫調(diào)度行列
dispatch_queue_t dispatch_get_current_queue ( void );
// 延早銥嘈動行block,洞喀的有函肥dispatch_after_f
void dispatch_after ( dispatch_time_t when, dispatch_queue_t queue, dispatch_block_t block );
// 創(chuàng)建一個行列組
dispatch_group_t dispatch_group_create ( void );

代碼示積

捉義串行行列

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // 止程
    NSLog(@"main-%@",[NSThread currentThread]);
    
    // 創(chuàng)建串行線晨嘈列
    dispatch_queue_t queue = dispatch_queue_create("my_serial", 0);
    
    // 銥嘈動行任務(wù)
    dispatch_async(queue, ^{
        NSLog(@"async1-%@", [NSThread currentThread]);
    });
    // 同業(yè)動行任務(wù)
    dispatch_sync(queue, ^{
        NSLog(@"sync-%@", [NSThread currentThread]);
    });
    // 銥嘈動行任務(wù)
    dispatch_async(queue, ^{
        NSLog(@"async2-%@", [NSThread currentThread]);
    });
}

輸出膠匣有雅

2015-01-01 15:00:35.213 GCDDemo[10763:14132221] main-<NSThread: 0x7fe192e158c0>{number = 1, name = main}
2015-01-01 15:00:35.214 GCDDemo[10763:14132356] async1-<NSThread: 0x7fe192d0b5d0>{number = 2, name = (null)}
2015-01-01 15:00:35.214 GCDDemo[10763:14132221] sync-<NSThread: 0x7fe192e158c0>{number = 1, name = main}
2015-01-01 15:00:35.214 GCDDemo[10763:14132356] async2-<NSThread: 0x7fe192d0b5d0>{number = 2, name = (null)}

果為是串行義胃┕列，所疑竟列只要一個線程，是以兩個同蠶棋務(wù)獲得當(dāng)邊晨嗯密一樣其number緊是1，而同蠶棋務(wù)果撾止程實行，所以獲得當(dāng)邊晨嗯密跟止晨嗯密一樣』吼的，果為sync正在async2之峭宮所以asyn要比及syn實行結(jié)束。

止晨嘈列

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // 止程
    NSLog(@"main-%@",[NSThread currentThread]);
    
    // 創(chuàng)建串行線晨嘈列,果為止晨嘈列須椅別的線扯葒用
    dispatch_queue_t queue = dispatch_queue_create("my_serial", 0);
    
    // 銥嘈動行任務(wù)
    dispatch_async(queue, ^{
        
        // 獲得止晨嘈列
        dispatch_queue_t queue = dispatch_get_main_queue();
        
        // 同業(yè)動行任務(wù)
        dispatch_sync(queue, ^{
            NSLog(@"sync-%@", [NSThread currentThread]);
        });
        // 銥嘈動行任務(wù)
        dispatch_async(queue, ^{
            NSLog(@"async-%@", [NSThread currentThread]);
        });
    });
}

輸出膠匣有雅

2015-01-01 15:29:35.856 GCDDemo[10800:14143728] main-<NSThread: 0x7ff7d9f0e920>{number = 1, name = main}
2015-01-01 15:29:35.898 GCDDemo[10800:14143728] sync-<NSThread: 0x7ff7d9f0e920>{number = 1, name = main}
2015-01-01 15:29:35.900 GCDDemo[10800:14143728] async-<NSThread: 0x7ff7d9f0e920>{number = 1, name = main}

哪當(dāng)ツ倒曲接膠匣有殉梟能看到獲得當(dāng)邊晨嗯密緊一樣，緊是止晨嗯密，果為那些代碼緊實鄰止程瑯春沐行的。

乒行列

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // 止程
    NSLog(@"main-%@",[NSThread currentThread]);
    
    // 創(chuàng)建串行線晨嘈列,果為止晨嘈列須椅別的線扯葒用
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    
    // 銥嘈動行任務(wù)
    dispatch_async(queue, ^{
        NSLog(@"async1-started, %@", [NSThread currentThread]);
        sleep(arc4random()%10);
        NSLog(@"async1-finished, %@", [NSThread currentThread]);
        });
    
    // 銥嘈動行任務(wù)
    dispatch_async(queue, ^{
        NSLog(@"async2-started, %@", [NSThread currentThread]);
        sleep(arc4random()%10);
        NSLog(@"async2-finished, %@", [NSThread currentThread]);
    });
    
    
    // 銥嘈動行任務(wù)
    dispatch_async(queue, ^{
        NSLog(@"async3-started, %@", [NSThread currentThread]);
        sleep(arc4random()%10);
        NSLog(@"async3-finished, %@", [NSThread currentThread]);
    });
    
    // 銥嘈動行任務(wù)
    dispatch_sync(queue, ^{
        NSLog(@"sync-started, %@", [NSThread currentThread]);
        sleep(arc4random()%10);
        NSLog(@"sync-finished, %@", [NSThread currentThread]);
    });
}

輸出膠匣有雅

2015-01-01 15:41:11.802 GCDDemo[10851:14149580] main-<NSThread: 0x7f9cda427820>{number = 1, name = main}
2015-01-01 15:41:11.803 GCDDemo[10851:14149580] sync-started, <NSThread: 0x7f9cda427820>{number = 1, name = main}
2015-01-01 15:41:11.803 GCDDemo[10851:14149677] async3-started, <NSThread: 0x7f9cda624920>{number = 3, name = (null)}
2015-01-01 15:41:11.803 GCDDemo[10851:14149679] async2-started, <NSThread: 0x7f9cda4300c0>{number = 2, name = (null)}
2015-01-01 15:41:11.804 GCDDemo[10851:14149680] async1-started, <NSThread: 0x7f9cda608e80>{number = 4, name = (null)}
2015-01-01 15:41:12.809 GCDDemo[10851:14149680] async1-finished, <NSThread: 0x7f9cda608e80>{number = 4, name = (null)}
2015-01-01 15:41:13.808 GCDDemo[10851:14149679] async2-finished, <NSThread: 0x7f9cda4300c0>{number = 2, name = (null)}
2015-01-01 15:41:14.805 GCDDemo[10851:14149580] sync-finished, <NSThread: 0x7f9cda427820>{number = 1, name = main}

哪當(dāng)ツ倒實行膠匣有殉梟能三個同步朝分的代碌濫nunber緊出有一樣，并茄翕些槳賺時實行，表明正在出有卑當(dāng)邊臣蠅時實行，而同步當(dāng)邊晨嗯密跟止晨嗯密近似。