ios - 在 block 函数内创建计时器时如何触发计时器？

Question

@interface Taxi_MainViewController : Taxi_BaseNavViewController
{
  __block NSTimer *timer_;
}



  [Taxi_do_order psg_place_orderWithMemberId:strMemberId_ orderStatus:K_orderStatus_open andCLLocationCoord:location.coordinate callback:^(NSInteger iOrderId){
        [Taxi_StatusView dismiss];
        if (iOrderId >=0)
        {
            isOrderExist = YES;
            [weakSelf_ showWaittingDriverAcceptView];
            timer_ =   [NSTimer scheduledTimerWithTimeInterval:2.0
                                                               target:weakSelf_
                                                             selector:@selector(actListen:)
                                                             userInfo:nil
                                                              repeats:YES];
        }else
            [weakSelf_ hideWaittingDriverAcceptView];
    }faile:^(){
        [Taxi_StatusView showLostNetWork];
    }];

当我调用[timer_ invalidate]时，timer_ = nil;在其他方法中，计时器函数仍然每 2 秒调用一次。

Answer 1

在你的例子中，变量 timer_ 永远不会保留，你失去了指针在结束 block 范围内。有了属性，你就有了保留/释放机制。

试试这个:

@interface Taxi_MainViewController : Taxi_BaseNavViewController
{

}

@property (nonatomic,retain) NSTimer* timer;

@end



[Taxi_do_order psg_place_orderWithMemberId:strMemberId_ orderStatus:K_orderStatus_open andCLLocationCoord:location.coordinate callback:^(NSInteger iOrderId){
        [Taxi_StatusView dismiss];
        if (iOrderId >=0)
        {
            isOrderExist = YES;
            [weakSelf_ showWaittingDriverAcceptView];
            self.timer =   [NSTimer scheduledTimerWithTimeInterval:2.0
                                                               target:weakSelf_
                                                             selector:@selector(actListen:)
                                                             userInfo:nil
                                                              repeats:YES];
        }else
            [weakSelf_ hideWaittingDriverAcceptView];
    }faile:^(){
        [Taxi_StatusView showLostNetWork];
    }];