- (void)test1 {
//创建一个并发队列
//并发队列+异步任务:创建多个线程，并发执行
dispatch_queue_t queue = dispatch_queue_create("tqh.com", DISPATCH_QUEUE_CONCURRENT);
//一步创建一个任务，任务不会立即执行
dispatch_async(queue, ^{
NSLog(@"1--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"2--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"3--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"4--%@--",[NSThread currentThread]);
});
NSLog(@"结束");
//number = 4, name = (null) 无序
}
- (void)test2 {
//并发队列+同步任务：不会开启新线程，在父线程中同步执行各个子线程，也就是逐一执行，并且是添加过任务后立即执行，之后才能添加下一个任务
dispatch_queue_t queue = dispatch_queue_create("tqh.com", DISPATCH_QUEUE_CONCURRENT);
dispatch_sync(queue, ^{
NSLog(@"1--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"2--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"3--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"4--%@--",[NSThread currentThread]);
});
NSLog(@"结束");
//number = 1, name = main 有序
}
- (void)test3 {
//串行队列+同步任务：不会开启新线程，在父线程中同步执行各个子线程，也就是逐一执行，并且是添加过任务后立即执行，之后才能添加下一个任务
dispatch_queue_t queue = dispatch_queue_create("tqh.com", DISPATCH_QUEUE_SERIAL);
dispatch_sync(queue, ^{
NSLog(@"1--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"2--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"3--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"4--%@--",[NSThread currentThread]);
});
NSLog(@"结束");
//number = 1, name = main 有序
}
- (void)test4 {
//串行队列+异步任务：创建新线程，但是只会创建一个新线程，所有的任务都是在这个子线程里执行，执行顺序按照添加任务 的先后顺序，并且不是立即执行，而是等整个方法
dispatch_queue_t queue = dispatch_queue_create("tqh.com", DISPATCH_QUEUE_SERIAL);
dispatch_async(queue, ^{
NSLog(@"1--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"2--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"3--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"4--%@--",[NSThread currentThread]);
});
NSLog(@"结束");
//number = 2,name = (null),创建了一个线程 有序
}
- (void)test5 {
//主队列+异步任务：不会创建新线程，所有的任务都是在这个父线程里执行，执行顺序按照添加任务 的先后顺序，并且不是立即执行，而是等整个方法结束后依次执行
dispatch_queue_t queue = dispatch_get_main_queue();
dispatch_async(queue, ^{
NSLog(@"1--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"2--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"3--%@--",[NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"4--%@--",[NSThread currentThread]);
});
NSLog(@"结束");
//number = 1, name = main 有序
}
- (void)test6 {
//这个会产生问题,死锁，添加任务到主队列的任务要求立即执行，但是主队列是串行队列，当前任务要求执行完当前任务在执行新添加的任务。结果就是:两个任务互相等待，产生死锁
dispatch_queue_t queue = dispatch_get_main_queue();
dispatch_sync(queue, ^{
NSLog(@"1--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"2--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"3--%@--",[NSThread currentThread]);
});
dispatch_sync(queue, ^{
NSLog(@"4--%@--",[NSThread currentThread]);
});
NSLog(@"结束");
//没有打印信息
}
//延时执行：没有NSObject和NsTimer精确度高
- (void)test7 {
NSLog(@"%@",[NSDate date]);
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
NSLog(@"%@",[NSDate date]);
});
}
//一次性代码
- (void)test8 {
for (int i = ; i < ; i ++) {
[self onece];
}
//只走了第一次
}
- (void)onece {
static dispatch_once_t once;
dispatch_once(&once, ^{
NSLog(@"只走一次%@",[NSThread currentThread]);
});
NSLog(@"----------------");
}
//快速迭代,顺序不稳定
- (void)test9 {
dispatch_apply(, dispatch_get_global_queue(, ), ^(size_t index) {
NSLog(@"%ld %@",index,[NSThread currentThread]);
});
//无序
}
//队列组
- (void)test10 {
dispatch_group_t group = dispatch_group_create();
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, );
// 先执行3个耗时操作
dispatch_group_async(group, queue, ^{
for (int i = ; i < ; i ++) {
NSLog(@"1--%@--",[NSThread currentThread]);
}
});
dispatch_group_async(group, queue, ^{
for (int i = ; i < ; i ++) {
NSLog(@"2--%@--",[NSThread currentThread]);
}
});
dispatch_group_async(group, queue, ^{
for (int i = ; i < ; i ++) {
NSLog(@"3--%@--",[NSThread currentThread]);
}
});
// 等到以上任务完成后才会执行这个notify任务
dispatch_group_notify(group, dispatch_get_main_queue(), ^{
NSLog(@"最后执行main--%@--",[NSThread currentThread]);
});
}