Java 改装多部分/表单数据图像（android）

我多次尝试创建自定义http连接，但现在我对多部分/表单数据使用libruary改进。我有一个错误：

java.lang.NoClassDefFoundError: com.squareup.okhttp.OkHttpClient
            at retrofit.client.OkClient.generateDefaultOkHttp(OkClient.java:35)
            at retrofit.client.OkClient.<init>(OkClient.java:44)
            at service.ServiceGenerator.createService(ServiceGenerator.java:14)
            at profile.Optional.onActivityResult(Optional.java:555)
            at android.app.Activity.dispatchActivityResult(Activity.java:4663)
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3131)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3178)
            at android.app.ActivityThread.access$1100(ActivityThread.java:134)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:154)
            at android.app.ActivityThread.main(ActivityThread.java:4624)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
            at dalvik.system.NativeStart.main(Native Method)

ServiceGenerator.class

上传服务

---

如果您使用的是gradle和android studio，请确保在build.gradle文件中编译了'com.squareup.okhttp:okhttp:2.2.0'

UploadPhotoRetroService service = ServiceGenerator.createService(UploadPhotoRetroService.class, "https://rest.senseloopcore.no/users/image");
                        TypedFile typedFile = new TypedFile("image/jpeg", fileName);
                        service.upload(typedFile, new Callback<String>() {
                            @Override
                            public void success(String result, Response response) {
                                Log.e("result", result);
                            }

                            @Override
                            public void failure(RetrofitError error) {
                                error.printStackTrace();
                            }
                        });

public class ServiceGenerator {
    private ServiceGenerator() {
    }

    public static <S> S createService(Class<S> serviceClass, String baseUrl) {
        RestAdapter.Builder builder = new RestAdapter.Builder()
                .setEndpoint(baseUrl)
                .setClient(new OkClient());

        RestAdapter adapter = builder.build();

        return adapter.create(serviceClass);
    }
}

public interface UploadPhotoRetroService {

    @Headers({
            "id: 123",
            "key: 222"
    })

    @Multipart
    @POST("/upload")
    void upload(@Part("Photo") TypedFile file, Callback<String> callback);
}