IOS-GCDマルチスレッド

同期&非同期:

 ： ； 。

シリアル&パラレル:

 dispatch_get_main_queue   --> 
 dispatch_get_global_queue --> ( )

簡単な例:

dispatch_async(dispatch_get_global_queue(0,0), ^{
    NSLog(@"Task Thread!");
    [NSThread sleepTimeInterval:3];
    dispatch_async(dispatch_get_main_queue(), ^{
        NSLog(@" UI Thread！")
    });
});

カスタムスレッド:

シリアル:同期スレッドであるカスタムスレッドを作成します.次の2つのdispatch_を実行します.asyncは、実際には同じスレッドであり、task 1とtask 2は前後順に実行されます.デフォルトNULLはDISPATCH_ですQUEUE_SEARIAL

dispatch_queue_t queue = dispatch_queue_create(@"gcd_queue", NULL);
dispatch_async(queue, ^{
    NSLog(@"task 1");
    [NSthread sleepForTimeInterval:2];
    NSLog(@"task 1 over");
});

dispatch_async(queue, ^{
    NSLog(@"task 2");
    [NSthread sleepForTimeInterval:2];
    NSLog(@"task 2 over");
});

パラレル:DISPATCH_QUEUE_CONCURRENTパラメータは、並列キューを作成します.

dispatch_queue_t queue = dispatch_queue_create(@"gcd_queue", DISPATCH_QUEUE_CONCURRENT);
dispatch_async(queue, ^{
    NSLog(@"task 1");
    [NSthread sleepForTimeInterval:2];
    NSLog(@"task 1 over");
});

dispatch_async(queue, ^{
    NSLog(@"task 2");
    [NSthread sleepForTimeInterval:2];
    NSLog(@"task 2 over");
});

GCD_グループの使用:

dispatch_queue_t queue = dispatch_queue_create(@"gcd_queue", DISPATCH_QUEUE_CONCURRENT);
// group
dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group, queue, ^{
    NSLog(@"task 1");
    [NSthread sleepForTimeInterval:2];
    NSLog(@"task 1 over");
});

dispatch_group_async(group, queue, ^{
    NSLog(@"task 2");
    [NSthread sleepForTimeInterval:2];
    NSLog(@"task 2 over");
});

dispatch_group_notify(group, queue, ^{
    NSLog(@"All task over!");
    dispatch_async(dispatch_get_main_queue(), ^{
        NSLog(@" UI Thread！")
    });
});

非同期スレッド制御方法:

dispatch_queue_t queue = dispatch_queue_create(@"gcd_queue", DISPATCH_QUEUE_CONCURRENT);
// group
dispatch_group_t group = dispatch_group_create();
// group
dispatch_group_enter(group);
    .
    .     // 
    .
// group
dispatch_group_leave(group);