IOS实现验证码倒计时功能（二）

 //发送验证码按钮  _sentCodeBtn = [[UIButton alloc] initWithFrame:CGRectMake(kScreenWidth - 27 - 4 - 94, CGRectGetMinY(_registerCodeFD.frame) + 4, 94, 40)];  [_sentCodeBtn setBackgroundColor:colorWithRGBA(0, 191, 191, 0.9)];  [_sentCodeBtn setTitle:@"发送验证码" forState:UIControlStateNormal];  [_sentCodeBtn.titleLabel setFont:[UIFont systemFontOfSize:13.0f]];  //设置圆角  [_sentCodeBtn.layer setCornerRadius:3.0f];  [_sentCodeBtn.layer setShouldRasterize:YES];  [_sentCodeBtn.layer setRasterizationScale:[UIScreen mainScreen].scale];  //发送事件  [_sentCodeBtn addTarget:self action:@selector(sentCodeMethod) forControlEvents:UIControlEventTouchUpInside];  [self.view addSubview:_sentCodeBtn];

//发送验证码-(void)sentCodeMethod{ NSLog(@"发送验证码。。"); //计时器发送验证码 [self sentPhoneCodeTimeMethod]; //调用发送验证码接口-》}//计时器发送验证码-(void)sentPhoneCodeTimeMethod{ //倒计时时间 - 60秒 __block NSInteger timeOut = 59; //执行队列 dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); //计时器 -》dispatch_source_set_timer自动生成 dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue); dispatch_source_set_timer(timer, DISPATCH_TIME_NOW, 1.0 * NSEC_PER_SEC, 0 * NSEC_PER_SEC); dispatch_source_set_event_handler(timer, ^{  if (timeOut <= 0) {   dispatch_source_cancel(timer);   //主线程设置按钮样式-》   dispatch_async(dispatch_get_main_queue(), ^{    [_sentCodeBtn setTitle:@"发送验证码" forState:UIControlStateNormal];    [_sentCodeBtn setUserInteractionEnabled:YES];   });  }else{   //开始计时   //剩余秒数 seconds   NSInteger seconds = timeOut % 60;   NSString *strTime = [NSString stringWithFormat:@"%.1ld",seconds];   //主线程设置按钮样式   dispatch_async(dispatch_get_main_queue(), ^{    [UIView beginAnimations:nil context:nil];    [UIView setAnimationDuration:1.0];    [_sentCodeBtn setTitle:[NSString stringWithFormat:@"%@S后重新发送",strTime] forState:UIControlStateNormal];    [UIView commitAnimations];    //计时器件不允许点击    [_sentCodeBtn setUserInteractionEnabled:NO];   });   timeOut--;  } }); dispatch_resume(timer);}