#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        // Do any additional setup after loading the view, typically from a nib.    NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(demo) object:nil];    [thread start];        [self performSelector:@selector(demo1) onThread:thread withObject:nil waitUntilDone:NO];   }- (void) demo {        NSLog(@"I am running");    //[[NSRunLoop currentRunLoop] run];    [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:2]];        NSLog(@"end");}- (void) demo1 {        NSLog(@"I am running on runloop");}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end@end复制代码