java.lang.ClassNotFoundException: Didn't find class "retrofit2.Callback"

[lucf1103]

                                                                        Caused by: java.lang.ClassNotFoundException: Didn't find class "retrofit2.Callback" on path: DexPathList[[zip file "/data/app/com.sse.android.xxx-2/base.apk"],nativeLibraryDirectories=[/data/app/com.sse.android.xxx-2/lib/arm, /system/fake-libs, /data/app/com.sse.android.xxx-2/base.apk!/lib/armeabi-v7a, /system/lib, /vendor/lib]]

集成遇到这个问题，请问怎么解决？按照网上的方法都试了，还是不行...

[lucf1103]

java.lang.NoClassDefFoundError: Failed resolution of: Lretrofit2/Callback;

Caused by: java.lang.ClassNotFoundException: Didn't find class "retrofit2.Callback" on path: DexPathList[[zip file "/data/app/com.sse.android.xxx-2/base.apk"],nativeLibraryDirectories=[/data/app/com.sse.android.xxx-2/lib/arm, /system/fake-libs, /data/app/com.sse.android.xxx-2/base.apk!/lib/armeabi-v7a, /system/lib, /vendor/lib]]

[ZhongXiaoHong]

retrofit 错误 大哥 检查一下你网络请求部分