iOS-计时器调用问题

我想在计时器过期时调用一个方法，但该方法没有被调用。不知道出了什么问题。有什么建议吗

被调用：

- (void)messageSendingReply:(id)messageID
{
    //Do something.
}

- (void)sendingMessageTimer_Start:(int64_t)sendingMsgID Time:(NSTimeInterval)replyDelay {

    NSMethodSignature *sig = [self methodSignatureForSelector:@selector(messageSendingReply:)];


    if (sig)
    {

        NSInvocation* invo = [NSInvocation invocationWithMethodSignature:sig];
        [invo setTarget:self];
        [invo setSelector:@selector(messageSendingReply:)];
        id obj= [NSNumber numberWithLongLong:sendingMsgID];
        [invo setArgument:&obj atIndex:0];
        [invo retainArguments];

        [self.replyTimerDic setValue:[NSTimer scheduledTimerWithTimeInterval:replyDelay invocation:invo repeats:NO] forKey:[NSString stringWithFormat:@"%qi",sendingMsgID]];

    }

}

调用上述命令：

- (void)messageSendingReply:(id)messageID
{
    //Do something.
}

- (void)sendingMessageTimer_Start:(int64_t)sendingMsgID Time:(NSTimeInterval)replyDelay {

    NSMethodSignature *sig = [self methodSignatureForSelector:@selector(messageSendingReply:)];


    if (sig)
    {

        NSInvocation* invo = [NSInvocation invocationWithMethodSignature:sig];
        [invo setTarget:self];
        [invo setSelector:@selector(messageSendingReply:)];
        id obj= [NSNumber numberWithLongLong:sendingMsgID];
        [invo setArgument:&obj atIndex:0];
        [invo retainArguments];

        [self.replyTimerDic setValue:[NSTimer scheduledTimerWithTimeInterval:replyDelay invocation:invo repeats:NO] forKey:[NSString stringWithFormat:@"%qi",sendingMsgID]];

    }

}

---

我通过在当前运行循环和运行中添加计时器解决了这个问题。谢谢

if (sig)
{
    NSInvocation* invo = [NSInvocation invocationWithMethodSignature:sig];
    [invo setTarget:self];
    [invo setSelector:@selector(messageSendingReply:)];
    id obj= [NSNumber numberWithLongLong:sendingMsgID];
    [invo setArgument:&obj atIndex:0];
    [invo retainArguments];

    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:replyDelay invocation:invo repeats:NO];

    [self.replyTimerDic setValue:timer forKey:[NSString stringWithFormat:@"%qi",sendingMsgID]];

    NSRunLoop* runLoop = [NSRunLoop currentRunLoop];
    [runLoop addTimer:timer forMode:NSRunLoopCommonModes];
    [runLoop run];
}

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是否将计时器添加到运行循环中？