animateWithDuration 无法识别？

Question

I'm trying to do a cross dissolve on three UILabels (display1, display2, display3), by using a block animation to fade out, change text and then fade them in one at a time. The code I'm using is:

[UIView animateWithDuration:1.0 delay: 1.0
    animations:^{
        display1.alpha = 0.0;
        display2.alpha = 0.0;
        display3.alpha = 0.0;
    }
    completion:^{
        [display1 setText:[NSString stringWithFormat:@"%@",[engine getstring]]];
        [display2 setText:[NSString stringWithFormat:@"%@",[engine getstring]]];
        [display3 setText:[NSString stringWithFormat:@"%@",[engine getstring]]];
        [UIView animateWithDuration:1.0 delay:1.0
            animations:^{
                display1.alpha = 1.0;
                [UIView animateWithDuration:1.0 delay:1.0
                    animations:^{
                        display2.alpha = 1.0;
                        [UIView animateWithDuration:1.0
                            delay:1.0
                            animations:^{
                                display3.alpha = 1.0;
                            } completion:nil];
                    } completion:nil];
        } completion:nil];
    }];

I get the following warnings:

Method '+animateWithDuration:delay:animations:completion:' not found*

and

'UIView' may not respond to method '+animateWithDuration:delay:animations:completion:'

I'm using Xcode 4.0 with an iOS Build Target of 4.3.

Answer 1

You want to use

+ animateWithDuration:delay:options:animations:completion:

instead. Note the options: in the middle.