Change client to retrofit2

app/src/main/java/com/github/gotify/api/Api.java

@@ -1,75 +1,4 @@
 package com.github.gotify.api;
 
-import android.app.Activity;
-import com.github.gotify.client.ApiCallback;
-import com.github.gotify.client.ApiException;
-import com.github.gotify.log.Log;
-import java.util.List;
-import java.util.Map;
-
 public class Api {
-    public static <T> CallExecutor<T> withLogging(ApiCall<T> call) {
-        return new CallExecutor<T>(call);
-    }
-
-    private static <T> Callback<T> loggingCallback() {
-        return Callback.call(
-                (data) -> {},
-                (exception) ->
-                        Log.e("Error while api call: " + exception.getResponseBody(), exception));
-    }
-
-    public interface ApiCall<T> {
-        void call(ApiCallback<T> callback) throws ApiException;
-    }
-
-    public static class CallExecutor<T> {
-        private ApiCall<T> call;
-
-        private CallExecutor(ApiCall<T> call) {
-            this.call = call;
-        }
-
-        public void handle(Callback<T> callback) {
-            Callback<T> merged = Callback.merge(callback, loggingCallback());
-            try {
-                call.call(fromCallback(merged));
-            } catch (ApiException e) {
-                merged.onError(e);
-            }
-        }
-
-        public void handleInUIThread(
-                Activity activity,
-                Callback.SuccessCallback<T> onSuccess,
-                Callback.ErrorCallback onError) {
-            handle(Callback.runInUIThread(activity, Callback.call(onSuccess, onError)));
-        }
-
-        public void handle(Callback.SuccessCallback<T> onSuccess, Callback.ErrorCallback onError) {
-            handle(Callback.call(onSuccess, onError));
-        }
-    }
-
-    private static <T> ApiCallback<T> fromCallback(Callback<T> callback) {
-        return new ApiCallback<T>() {
-            @Override
-            public void onFailure(
-                    ApiException e, int statusCode, Map<String, List<String>> responseHeaders) {
-                callback.onError(e);
-            }
-
-            @Override
-            public void onSuccess(
-                    T result, int statusCode, Map<String, List<String>> responseHeaders) {
-                callback.onSuccess(result);
-            }
-
-            @Override
-            public void onUploadProgress(long bytesWritten, long contentLength, boolean done) {}
-
-            @Override
-            public void onDownloadProgress(long bytesRead, long contentLength, boolean done) {}
-        };
-    }
 }

app/src/main/java/com/github/gotify/api/ApiException.java

@@ -0,0 +1,4 @@
+package com.github.gotify.api;
+
+class ApiException {
+}