Android 在运行时检查依赖可用性

Question

Let's say I add the following dependency to my app level build.gradle file:

compile 'com.squareup.retrofit2:retrofit:2.3.0'

How can I check at runtime that a certain dependency exists or not?

Answer 1

You would not be able to run the App in the first place, because if the dependency does not exist you can not build the .apk . There is no run-time checking for gradle dependencies.

Answer 2

I was looking for the same and I couldn't find the answer. What I would do is the following:

1. if you do have the dependency at compilation time , then I would call any method from that library surrounded by try/catch :

    try { Retrofit().whateverRetrofitApi() // if you get to this line it means the library is present } catch(e: Throwable) { // if you get to this line it means the library is not present }

Probably some other exception/error like NoClassDefFoundError would be better to catch.

2. if you do not have the dependency at compilation time , and you do want to check if it's present at runtime , then you could perform the same thing, but use reflection instead.

Hope it helps