NSTimer userInfo。 对象如何传递给选择器？

Question

I have this code:

-(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;
}

The target is start rotating a view while user holds a button. When user releases it the timer will stop.

But I'm giving this:

-[__NSCFTimer intValue]: unrecognized selector sent to instance 0x4ae360

But if I'm paasing in userInfo a NSNumber class, why I'm receiving the timer?

Thanks.

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