延时操作的三种方式
- (void)delay
{
// 1. NSThread
[self performSelector:@selector(run) withObject:nil afterDelay:2.0];
// 2. NSTimer
[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(run) userInfo:nil repeats:NO];
// 3. GCD
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
NSLog(@"run-----");
});
}
同步函数 + 主队列：
- (void)syncMain
{
// 1.获得主队列
dispatch_queue_t queue = dispatch_get_main_queue();
// 2.将任务加入队列
dispatch_sync(queue, ^{
NSLog(@"1-----%@", [NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"2-----%@", [NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"3-----%@", [NSThread currentThread]);
});
}
异步函数 + 主队列：只在主线程中执行任务
- (void)asyncMain
{
// 1.获得主队列
dispatch_queue_t queue = dispatch_get_main_queue();
// 2.将任务加入队列
dispatch_async(queue, ^{
NSLog(@"1-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"2-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"3-----%@", [NSThread currentThread]);
});
}
同步函数 + 串行队列：不会开启新的线程，在当前线程执行任务。任务是串行的，执行完一个任务，再执行下一个任务
- (void)syncSerial
{
// 1.创建串行队列
dispatch_queue_t queue = dispatch_queue_create("com.520it.queue", DISPATCH_QUEUE_SERIAL);
// 2.将任务加入队列
dispatch_sync(queue, ^{
NSLog(@"1-----%@", [NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"2-----%@", [NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"3-----%@", [NSThread currentThread]);
});
}
异步函数 + 串行队列：会开启新的线程，但是任务是串行的，执行完一个任务，再执行下一个任务
- (void)asyncSerial
{
// 1.创建串行队列
dispatch_queue_t queue = dispatch_queue_create("com.520it.queue", DISPATCH_QUEUE_SERIAL);
// dispatch_queue_t queue = dispatch_queue_create("com.520it.queue", NULL);
// 2.将任务加入队列
dispatch_async(queue, ^{
NSLog(@"1-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"2-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"3-----%@", [NSThread currentThread]);
});
}
同步函数 + 并发队列：不会开启新的线程
- (void)syncConcurrent
{
// 1.获得全局的并发队列
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
// 2.将任务加入队列
dispatch_sync(queue, ^{
NSLog(@"1-----%@", [NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"2-----%@", [NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"3-----%@", [NSThread currentThread]);
});
}
异步函数 + 并发队列：可以同时开启多条线程
- (void)asyncConcurrent
{
// 1.创建一个并发队列
// label : 相当于队列的名字
// dispatch_queue_t queue = dispatch_queue_create("com.520it.queue", DISPATCH_QUEUE_CONCURRENT);
// 1.获得全局的并发队列
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
// 2.将任务加入队列
dispatch_async(queue, ^{
for (NSInteger i = 0; i<10; i++) {
NSLog(@"1-----%@", [NSThread currentThread]);
}
});
dispatch_async(queue, ^{
for (NSInteger i = 0; i<10; i++) {
NSLog(@"2-----%@", [NSThread currentThread]);
}
});
dispatch_async(queue, ^{
for (NSInteger i = 0; i<10; i++) {
NSLog(@"3-----%@", [NSThread currentThread]);
}
});
}
GCD其他常用函数
// dispatch_async(<#dispatch_queue_t queue#>, <#^(void)block#>);
// dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
// dispatch_async_f(queue, NULL, download);
- (void)group
{
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
// 创建一个队列组
dispatch_group_t group = dispatch_group_create();
// 1.下载图片1
dispatch_group_async(group, queue, ^{
// 图片的网络路径
NSURL *url = [NSURL URLWithString:@"http://img.pconline.com.cn/images/photoblog/9/9/8/1/9981681/200910/11/1255259355826.jpg"];
NSData *data = [NSData dataWithContentsOfURL:url];
self.image1 = [UIImage imageWithData:data];
});
// 2.下载图片2
dispatch_group_async(group, queue, ^{
// 图片的网络路径
NSURL *url = [NSURL URLWithString:@"http://pic38.nipic.com/20140228/5571398_215900721128_2.jpg"];
NSData *data = [NSData dataWithContentsOfURL:url];
// 生成图片
self.image2 = [UIImage imageWithData:data];
});
// 3.将图片1、图片2合成一张新的图片
dispatch_group_notify(group, queue, ^{
// 开启新的图形上下文
UIGraphicsBeginImageContext(CGSizeMake(100, 100));
// 绘制图片
[self.image1 drawInRect:CGRectMake(0, 0, 50, 100)];
[self.image2 drawInRect:CGRectMake(50, 0, 50, 100)];
// 取得上下文中的图片
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
// 结束上下文
UIGraphicsEndImageContext();
// 回到主线程显示图片
dispatch_async(dispatch_get_main_queue(), ^{
// 4.将新图片显示出来
self.imageView.image = image;
});
});
}
/**
* 快速迭代
*/
- (void)apply
{
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
NSString *from = @"/Users/xiaomage/Desktop/From";
NSString *to = @"/Users/xiaomage/Desktop/To";
NSFileManager *mgr = [NSFileManager defaultManager];
NSArray *subpaths = [mgr subpathsAtPath:from];
dispatch_apply(subpaths.count, queue, ^(size_t index) {
NSString *subpath = subpaths[index];
NSString *fromFullpath = [from stringByAppendingPathComponent:subpath];
NSString *toFullpath = [to stringByAppendingPathComponent:subpath];
// 剪切
[mgr moveItemAtPath:fromFullpath toPath:toFullpath error:nil];
NSLog(@"%@---%@", [NSThread currentThread], subpath);
});
}
/**
* 传统文件剪切
*/
- (void)moveFile
{
NSString *from = @"/Users/xiaomage/Desktop/From";
NSString *to = @"/Users/xiaomage/Desktop/To";
NSFileManager *mgr = [NSFileManager defaultManager];
NSArray *subpaths = [mgr subpathsAtPath:from];
for (NSString *subpath in subpaths) {
NSString *fromFullpath = [from stringByAppendingPathComponent:subpath];
NSString *toFullpath = [to stringByAppendingPathComponent:subpath];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// 剪切
[mgr moveItemAtPath:fromFullpath toPath:toFullpath error:nil];
});
}
}
- (void)barrier
{
dispatch_queue_t queue = dispatch_queue_create("12312312", DISPATCH_QUEUE_CONCURRENT);
dispatch_async(queue, ^{
NSLog(@"----1-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"----2-----%@", [NSThread currentThread]);
});
dispatch_barrier_async(queue, ^{
NSLog(@"----barrier-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"----3-----%@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"----4-----%@", [NSThread currentThread]);
});
}
GCD定时器
// dispatch_time_t when = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC));
// dispatch_after(when, dispatch_get_main_queue(), ^{
// NSLog(@"-------");
// });
int count = 0;
// 获得队列
// dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
dispatch_queue_t queue = dispatch_get_main_queue();
// 创建一个定时器(dispatch_source_t本质还是个OC对象)
self.timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
// 设置定时器的各种属性（几时开始任务，每隔多长时间执行一次）
// GCD的时间参数，一般是纳秒（1秒 == 10的9次方纳秒）
// 何时开始执行第一个任务
// dispatch_time(DISPATCH_TIME_NOW, 1.0 * NSEC_PER_SEC) 比当前时间晚3秒
dispatch_time_t start = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC));
uint64_t interval = (uint64_t)(1.0 * NSEC_PER_SEC);
dispatch_source_set_timer(self.timer, start, interval, 0);
// 设置回调
dispatch_source_set_event_handler(self.timer, ^{
NSLog(@"------------%@", [NSThread currentThread]);
count++;
// if (count == 4) {
// // 取消定时器
// dispatch_cancel(self.timer);
// self.timer = nil;
// }
});
// 启动定时器
dispatch_resume(self.timer);
