nstimer userinfo。对象如何传递给选择器？

Question

我有这个代码：

-(void)startRotation:(RDUtilitiesBarRotation)mode {
    rotationTimer = [NSTimer scheduledTimerWithTimeInterval:0.1f target:self selector:@selector(rotateSelectedItem:) userInfo:[NSNumber numberWithInt:mode] repeats:YES];
}
-(void)rotateSelectedItem:(NSNumber*)sender {
    float currAngle = [selectedItem currentRotation];
    if ([sender intValue] == RDUtilitiesBarRotationLeft) {
        [selectedItem rotateImage:currAngle - 1];
    }
    else {
        [selectedItem rotateImage:currAngle + 1];
    }
}
-(void)stopRotation {
    [rotationTimer invalidate];
    rotationTimer = nil;
}

.

目标是在用户保存按钮时旋转视图。当用户释放它时，计时器将停止。

但我给出这个：

- [__ nscfterimer intvalue]：无法识别选择器发送到实例0x4ae360

但如果我在UserInfo中保存了一个NSNumber类，为什么我收到定时器？

谢谢。

Answer 1

Your timer action method should look like this

-(void)rotateSelectedItem:(NSTimer*)sender

You can get at the userInfo by doing

NSNumber *userInfo = sender.userInfo;

Answer 2

You misunderstood the signature of the selector that you register with the timer. The sender is NSTimer*, not the userInfo object that you pass into its constructor:

-(void)rotateSelectedItem:(NSTimer*)sender
{
    float currAngle = [selectedItem currentRotation];
    if ([sender.userInfo intValue] == RDUtilitiesBarRotationLeft)
    {
        [selectedItem rotateImage:currAngle - 1];
    }
    else
    {
        [selectedItem rotateImage:currAngle + 1];
    }
}

Answer 3

From the documentation:

The message to send to target when the timer fires. The selector must have the following signature:

- (void)timerFireMethod:(NSTimer*)theTimer