/延遲呼叫
[selfperformSelector:@selector(doSomeThing:) withObject:nilafterDelay:1.0f];

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

        [selfdoSomeThing:nil];
});

[NSTimerscheduledTimerWithTimeInterval:2.0ftarget:selfselector

:@selector(doSomeThing:) userInfo:nilrepeats:NO];

    
[NSThreadsleepForTimeInterval:5.0f];

//在主執行緒呼叫
[selfperformSelectorOnMainThread:@selector(doSomeThing:) withObject:nilwaitUntilDone:YES];
    
[selfperformSelector:@selector(doSomeThing:) onThread:[NSThreadmainThread] withObject:nilwaitUntilDone:YES];
    
dispatch_sync(dispatch_get_main_queue(), ^{
        [selfdoSomeThing:nil];
});
    
//開闢新執行緒執行任務  [NSThreaddetachNewThreadSelector:@selector(doSomeThing:) toTarget:selfwithObject:nil];
    
//後臺呼叫
[selfperformSelectorInBackground:@selector(doSomeThing:) withObject:@"string"];