UIImageView Animation delay between frames?

问题:

I am trying to create an animation using a UIImageView with an array if images. It works great, except that I need a different delay between some of the frames. In an animated gif you can set the delay between frames. Every example I see of an animated UIImageView has a fixed delay between images.

Does anyone know how I can set a different delay between frames? Or, is there an example of such?

Maybe UIImageView is not the right thing to use, so if anyone has an alternative please let me know.

I have posted a similiar question in other forums and no one seems to be able to answer this. It seems like it should bo doable, since .gif images have had this forever.

Thanks

回答1:

It may seem hacky, but:

From UIImageView documentation:

animationImages

An array of UIImage objects to use for an animation.

@property(nonatomic, copy) NSArray *animationImages

Discussion

The array must contain UIImage objects. You may use the same image object more than once in the array. Setting this property to a value other than nil hides the image represented by the image property. The value of this property is nil by default.

So you need to add your UIImage several times to the array for a delay.

回答2:

UIImageView does not support a different delay between different images. You will have to use multiple UIImageViews and manage the transition between them manually if you want to have different delays between frames.

Another approach would be to use a UIWebView which is sized exactly to fit a .gif image that has the delay settings you want.

回答3:

You have to use different UIImageView to get this working. Try this application page. Might be helpful for you. Link: http://www.raywenderlich.com/2454/how-to-use-uiview-animation-tutorial

回答4:

If you would like to try my animation library in your iOS app, it offers a complete solution to this problem. For example, you could take a look at the APNG app, it is a free app in the iTunes store that displays animated APNG files. This app was created using my AVAnimator library which contains APNG and GIF decoding support. The APNG format works just like a GIF in the sense that each frame can have a delay time, you would use existing software to create the APNG in this case. But, it is easier to just encode a new .mvid file (this is a custom video file format) from a series of PNG imags. To create a longer delay, you simply repeat frames that do not change in the input PNG image series. Either approach could be used to create an input movie that could display with a variable amount of time in between specific frames (the overall FPS would be the same, but specific frames can simply repeat so that they do not change for say N frames in a row). You can also implement specific user interactions like starting an animation, pausing on a specific frame, and then starting again from that same frame.