GCD常用函数

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1. ios延迟执行的几种方法

[selfperformSelector:@selector(方法)withObject:nilafterDelay:2.0];

[NSTimerscheduledTimerWithTimeInterval:2.0target:selfselector:@selector(方法)userInfo:nilrepeats:NO];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)),dispatch_get_main_queue(), ^{

NSLog(@"");

});

gcd方式的优势：

可以控制在xx时间之后在哪个线程中执行。

2. GCD一次性代码：在程序的运行过程中只被执行一次

-(void)once{    static dispatch_once_t onceToken;    dispatch_once(&onceToken, ^{        NSLog(@"一次性代码")    });}

3.栅栏函数

注意：栅栏函数不能使用全局并发队列

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{            dispatch_queue_t queue=dispatch_queue_create("test", DISPATCH_QUEUE_CONCURRENT);    dispatch_async(queue, ^{                NSLog(@"test一，当前线程是%@",[NSThread currentThread]);    });            dispatch_async(queue, ^{                NSLog(@"test二，当前线程是%@",[NSThread currentThread]);    });        dispatch_barrier_async(queue, ^{        NSLog(@"我是栅栏++++++++++++++++++++++++++++++++++++++++++++");    });        dispatch_async(queue, ^{                NSLog(@"test三，当前线程是%@",[NSThread currentThread]);    });    }@end

4.GCD快速迭代

一共要传3个参数：

参数1；次数

参数2：队列（只能传并发队列，主队列会发生死锁串行队列无作用）

参数3：索引 index

转移文件夹内容代码

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    [self moveFileGCD];}-(void)moveFile{    //1.获取文件夹地址    NSString *from =@"文件夹地址";    NSString *to=@"文件夹地址";            //获取目录下面的文件的路径    NSArray *subpaths = [[NSFileManager defaultManager]subpathsAtPath:from];        NSLog(@"内容：%@",subpaths);        //遍历所有的文件    NSInteger count=subpaths.count;            for (NSInteger i=0; i<count ; i++) {        //拼接文件的全路径        NSString *fullPath=[from stringByAppendingPathComponent:subpaths[i]];        NSString *toFullPath=[to stringByAppendingPathComponent:subpaths[i]];                        [[NSFileManager defaultManager]moveItemAtPath:fullPath toPath:toFullPath error:nil];                NSLog(@"全路径：%@------------------全路径：%@-----------%@",fullPath,toFullPath,[NSThread currentThread]);            }}-(void)moveFileGCD{    //1.获取文件夹地址    NSString *from =@"文件夹地址";    NSString *to=@"文件夹地址";            //获取目录下面的文件的路径    NSArray *subpaths = [[NSFileManager defaultManager]subpathsAtPath:from];        NSLog(@"内容：%@",subpaths);    NSInteger count=subpaths.count;    //创建并发队列    dispatch_queue_t quque=dispatch_queue_create("queue", DISPATCH_QUEUE_CONCURRENT);    dispatch_apply(count, quque, ^(size_t i) {        //拼接文件的全路径        NSString *fullPath=[from stringByAppendingPathComponent:subpaths[i]];        NSString *toFullPath=[to stringByAppendingPathComponent:subpaths[i]];                        [[NSFileManager defaultManager]moveItemAtPath:fullPath toPath:toFullPath error:nil];                NSLog(@"全路径：%@------------------全路径：%@-----------%@",fullPath,toFullPath,[NSThread currentThread]);            });}@end

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