【iOS】GCD 2个队列 插队

线程lineOne 执行任务期间，让lineTwo任务执行后，再执行剩下的lineOne任务。

//  Created by SmartGao on 17/4/25.
//  Copyright © 2017年 gc. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@property (nonatomic, strong) dispatch_queue_t lineOne;
@property (nonatomic, strong) dispatch_queue_t lineTwo;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
   
    // DISPATCH_QUEUE_SERIAL 串行队列
    _lineOne = dispatch_queue_create("test.lineOne", DISPATCH_QUEUE_SERIAL);
    _lineTwo = dispatch_queue_create("test.lineTwo", DISPATCH_QUEUE_SERIAL);
    
    // 使用dispatch_set_target_queue()实现队列的动态调度管理
    dispatch_set_target_queue(_lineOne, _lineTwo);
    
    for (NSInteger i = 0; i < 20; i++) {
        dispatch_async(_lineOne, ^{
            [NSThread sleepForTimeInterval:1.0];
            NSLog(@"lineOne: %ld ",i);
        });
    }
    
    dispatch_async(_lineOne, ^{
        NSLog(@"全部完成 ");
    });
    
}

- (IBAction)buttonAction:(id)sender {
    // 这时则只会暂停dispatchA上原来的block的执行，dispatchB的block则不受影响。而如果暂停dispatchB的运行，则会暂停dispatchA的运行。
    dispatch_suspend(_lineOne);
    dispatch_async(_lineTwo, ^{
        NSLog(@"lineTwo插队！！");
        dispatch_resume(_lineOne);
    });
    
}