The UIKeyboardAnimationCurveUserInfoKey
has a UIViewAnimationCurve
value. How do I convert it to the corresponding UIViewAnimationOptions
value for use with the options
argument of +[UIView animateWithDuration:delay:options:animations:completion:]
?
// UIView.h
typedef enum {
UIViewAnimationCurveEaseInOut, // slow at beginning and end
UIViewAnimationCurveEaseIn, // slow at beginning
UIViewAnimationCurveEaseOut, // slow at end
UIViewAnimationCurveLinear
} UIViewAnimationCurve;
// ...
enum {
// ...
UIViewAnimationOptionCurveEaseInOut = 0 << 16, // default
UIViewAnimationOptionCurveEaseIn = 1 << 16,
UIViewAnimationOptionCurveEaseOut = 2 << 16,
UIViewAnimationOptionCurveLinear = 3 << 16,
// ...
};
typedef NSUInteger UIViewAnimationOptions;
Obviously, I could create a simple category method with a switch
statement, like so:
// UIView+AnimationOptionsWithCurve.h
@interface UIView (AnimationOptionsWithCurve)
@end
// UIView+AnimationOptionsWithCurve.m
@implementation UIView (AnimationOptionsWithCurve)
+ (UIViewAnimationOptions)animationOptionsWithCurve:(UIViewAnimationCurve)curve {
switch (curve) {
case UIViewAnimationCurveEaseInOut:
return UIViewAnimationOptionCurveEaseInOut;
case UIViewAnimationCurveEaseIn:
return UIViewAnimationOptionCurveEaseIn;
case UIViewAnimationCurveEaseOut:
return UIViewAnimationOptionCurveEaseOut;
case UIViewAnimationCurveLinear:
return UIViewAnimationOptionCurveLinear;
}
}
@end
But, is there an even easier/better way?
The category method you suggest is the “right” way to do it—you don’t necessarily have a guarantee of those constants keeping their value. From looking at how they’re defined, though, it seems you could just do
animationOption = animationCurve << 16;
...possibly with a cast to NSUInteger and then to UIViewAnimationOptions, if the compiler feels like complaining about that.