15、摇奖机案例
摇奖机案例
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UILabel *lbl1;
@property (weak, nonatomic) IBOutlet UILabel *lbl2;
@property (weak, nonatomic) IBOutlet UILabel *lbl3;
@property (weak, nonatomic) IBOutlet UIButton *startButton;
//全局队列
@property (nonatomic, strong) NSOperationQueue *queue;
@end
@implementation ViewController
//懒加载
- (NSOperationQueue *)queue {
if (_queue == nil) {
_queue = [NSOperationQueue new];
}
return _queue;
}
//点击开始执行
- (IBAction)start:(UIButton *)sender {
//当队列中有操作的时候，不添加操作
if (self.queue.operationCount == 0) {
//异步执行 添加操作
[self.queue addOperationWithBlock:^{
[self random];
}];
[self.startButton setTitle:@"暂停" forState:UIControlStateNormal];
self.queue.suspended = NO;
}else if(!self.queue.isSuspended) {
//正在执行的时候，暂停
//先把当前的操作执行完毕，暂停后续的操作
self.queue.suspended = YES;
[self.startButton setTitle:@"继续" forState:UIControlStateNormal];
}
}
//随机生成3个数字，显示到label上
- (void)random {
while (!self.queue.isSuspended) {
[NSThread sleepForTimeInterval:0.05];
//生成随机数 [0,10) 0-9
int num1 = arc4random_uniform(10);
int num2 = arc4random_uniform(10);
int num3 = arc4random_uniform(10);
//回到主线程上更新UI
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
//给label赋值
self.lbl1.text = [NSString stringWithFormat:@"%d",num1];
self.lbl2.text = [NSString stringWithFormat:@"%d",num2];
self.lbl3.text = [NSString stringWithFormat:@"%d",num3];
}];
}
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(@"%zd",self.queue.operationCount);
}
@end