mattdipasquale mattdipasquale - 1 year ago 130
iOS Question

iOS: How to convert UIViewAnimationCurve to UIViewAnimationOptions?

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?

Answer Source

Arguably you can take your first solution and make it an inline function to save yourself the stack push. It's such a tight conditional (constant-bound, etc) that it should compile into a pretty tiny piece of assembly.

Edit: Per @matt, here you go:

static inline UIViewAnimationOptions animationOptionsWithCurve(UIViewAnimationCurve curve)
{
  switch (curve) {
    case UIViewAnimationCurveEaseInOut:
        return UIViewAnimationOptionCurveEaseInOut;
    case UIViewAnimationCurveEaseIn:
        return UIViewAnimationOptionCurveEaseIn;
    case UIViewAnimationCurveEaseOut:
        return UIViewAnimationOptionCurveEaseOut;
    case UIViewAnimationCurveLinear:
        return UIViewAnimationOptionCurveLinear;
  }
}
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