conditionally implement an interface

Question

So I'm trying to do some animations in my app and had a way to do it without using ObjectAnimator and AnimatorListener from API 11. However, they're not as smooth and robust as just doing animations using those classes.

So I made the changes to my code in my object's class with a check for the API level, so that ObjectAnimator and AnimatorListener stuff wouldn't be called unless the API level is 11+.

The problem is that my object is implementing AnimatorListener even though its functionality isn't being used in all versions of the code. I think this is leading to an VerifyError on start up of my app because now it crashes on devices with API level 10 and down.

Is there a way to conditionally implement an interface based on the API level or a different way to achieve the same thing?

Thanks!

score 3 · Answer 1 · answered May 09 '13 at 20:11

3

You can try using https://github.com/JakeWharton/NineOldAndroids/ which backports the animation UI to pre-11.

answered May 09 '13 at 20:11

Gabe Sechan

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score 3 · Accepted Answer · answered May 09 '13 at 20:39

actually, it is OK if you build against or with a higher SDK target, the issue is only when your code is really run on a device missing classes from a higher SDK. As others suggested, you can go for a factory

public class Factory {
  public static <T> T getImplementation(){
    if(<SDK_LEVEL_INCOMPATIBLE>){
      return (T)new <package>.OldSchoolAnimator();
    }else{
      return (T)new <package>.SuperAnimator();
    }
  }
}


...
SomeImplementation impl = new Factory().getImplementation();
...

watchout, "SomeImplementation" has to be a common super-type or interface of OldSchoolAnimator and SuperAnimator classes! Dont use "imports" for implementation classes in your factory, rather use full-qualified classnames.

score 2 · Answer 3 · answered May 09 '13 at 20:12

2

I think you are looking for the factory design pattern:

http://en.wikipedia.org/wiki/Factory_method_pattern

answered May 09 '13 at 20:12

jan

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Perhaps provide a relevant example rather than just a link. Withholding +1 until I see more effort :D – christopher May 09 '13 at 20:17

score 0 · Answer 4 · answered May 09 '13 at 21:10

0

I ended up using an anonymous inner class for the listener and used the full-qualified classnames instead of importing the other animation objects!

answered May 09 '13 at 21:10

corgichu

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conditionally implement an interface

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