@interface ViewController () @property (nonatomic, strong) NSMutableArray * array; @property (nonatomic, strong) NSCondition * condition; @property (nonatomic, strong) NSTimer * timer; @end @implementation ViewController //初始化 - (NSMutableArray *)array { if (!_array) { _array = [NSMutableArray array]; } return _array; } - (NSCondition *)condition { if (!_condition) { _condition = [[NSCondition alloc] init]; } return _condition; } //加载 - (void)viewDidLoad { [super viewDidLoad]; //购买 for (int i = 0; i<3; i++) { [self performSelectorInBackground:@selector(_consumer) withObject:nil]; } //生产 self.timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(_productor) userInfo:nil repeats:YES]; } - (void)_productor { [self.condition lock]; if (self.array.count != 0) { NSLog(@"结束"); [self.timer invalidate]; self.timer = nil; } else { [self.array addObject:@"aaa"]; NSLog(@"生产完成!"); [self.condition signal]; } [self.condition unlock]; } - (void)_consumer { [self.condition lock]; if (self.array.count <= 0) { NSLog(@"正在等待!"); [self.condition wait]; } [self.array removeLastObject]; NSLog(@"购买成功!"); [self.condition unlock]; } @end