如何从函数onResponse of Retrofit返回值? [英] How can I return value from function onResponse of Retrofit?
问题描述
我正在尝试在改装
呼叫请求中返回我从 onResponse
方法获得的值,是否存在一种方法,我可以从覆盖的方法中获得这个价值?这是我的代码:
public JSONArray RequestGR(LatLng start,LatLng end)
{
final JSONArray jsonArray_GR;
EndpointInterface loginService = ServiceAuthGenerator.createService(EndpointInterface.class);
电话< GR> call = loginService.getroutedriver();
call.enqueue(新回调< GR>(){
@Override
public void onResponse(响应< GR>响应,Retrofit改装)
{
jsonArray_GR = response.body()。getRoutes();
//我需要在我的RequestGR方法中返回这个jsonArray_GR
}
@Override
public void onFailure(Throwable t){
}
});
返回jsonArray_GR;
}
我无法获得的值jsonArray_GR
因为能够在 onResponse
方法中使用它我需要将其声明为final并且我不能给它一个值。
问题是你试图同步返回 enqueue
的值,但它是使用回调的异步方法,所以你不能这样做。您有2个选项:
- 您可以更改
RequestGR
方法以接受回调然后将enqueue
回调链接到它。这类似于rxJava等框架中的映射。
这看起来大致如下:
public void RequestGR(LatLng start,LatLng end,final Callback< JSONArray> arrayCallback)
{
EndpointInterface loginService = ServiceAuthGenerator.createService( EndpointInterface.class);
电话< GR> call = loginService.getroutedriver();
call.enqueue(新回调< GR>(){
@Override
public void onResponse(响应< GR>响应,Retrofit改装)
{
JSONArray jsonArray_GR = response.body()。getRoutes();
arrayCallback.onResponse(jsonArray_GR);
}
@Override
public void onFailure(Throwable t){
//错误处理?arrayCallback.onFailure(t)?
}
});
}
这种方法的警告是它只是将异步内容推到另一个层次,这可能是你的问题。
- 你可以使用类似于
的对象BlockingQueue
,承诺
或Observable
甚至是你自己的容器对象(小心成为线程)安全),允许您检查和设置值。
这看起来像:
public BlockingQueue< JSONArray> RequestGR(LatLng start,LatLng end)
{
//您可以在回调之外创建最终容器对象,然后从回调内部将值传递给它。
final BlockingQueue< JSONArray> blockingQueue = new ArrayBlockingQueue<>(1);
EndpointInterface loginService = ServiceAuthGenerator.createService(EndpointInterface.class);
电话< GR> call = loginService.getroutedriver();
call.enqueue(新回调< GR>(){
@Override
public void onResponse(响应< GR>响应,Retrofit改装)
{
JSONArray jsonArray_GR = response.body()。getRoutes();
blockingQueue.add(jsonArray_GR);
}
@Override
public void onFailure(Throwable t){
}
});
返回blockingQueue;
}
然后您可以在调用方法中同步等待结果,如下所示:
BlockingQueue< JSONArray> result = RequestGR(42,42);
JSONArray value = result.take(); //这将阻止你的线程
我强烈建议你阅读像rxJava这样的框架。 / p>
I'm trying to return a value that i get from onResponse
method in retrofit
call request, is there a way that i can get that value out of the overrided method? here is my code:
public JSONArray RequestGR(LatLng start, LatLng end)
{
final JSONArray jsonArray_GR;
EndpointInterface loginService = ServiceAuthGenerator.createService(EndpointInterface.class);
Call<GR> call = loginService.getroutedriver();
call.enqueue(new Callback<GR>() {
@Override
public void onResponse(Response<GR> response , Retrofit retrofit)
{
jsonArray_GR = response.body().getRoutes();
//i need to return this jsonArray_GR in my RequestGR method
}
@Override
public void onFailure(Throwable t) {
}
});
return jsonArray_GR;
}
i can't get the value of jsonArray_GR
because to be able to use it in onResponse
method i need to declare it final and i can't give it a value.
The problem is you are trying to synchronously return the value of enqueue
, but it is an asynchronous method using a callback so you can't do that. You have 2 options:
- You can change your
RequestGR
method to accept a callback and then chain theenqueue
callback to it. This is similar to mapping in frameworks like rxJava.
This would look roughly like:
public void RequestGR(LatLng start, LatLng end, final Callback<JSONArray> arrayCallback)
{
EndpointInterface loginService = ServiceAuthGenerator.createService(EndpointInterface.class);
Call<GR> call = loginService.getroutedriver();
call.enqueue(new Callback<GR>() {
@Override
public void onResponse(Response<GR> response , Retrofit retrofit)
{
JSONArray jsonArray_GR = response.body().getRoutes();
arrayCallback.onResponse(jsonArray_GR);
}
@Override
public void onFailure(Throwable t) {
// error handling? arrayCallback.onFailure(t)?
}
});
}
The caveat with this approach is it just pushes the async stuff up another level, which might be a problem for you.
- You can use an object similar to a
BlockingQueue
,Promise
or anObservable
or even your own container object (be careful to be thread safe) that allows you to check and set the value.
This would look like:
public BlockingQueue<JSONArray> RequestGR(LatLng start, LatLng end)
{
// You can create a final container object outside of your callback and then pass in your value to it from inside the callback.
final BlockingQueue<JSONArray> blockingQueue = new ArrayBlockingQueue<>(1);
EndpointInterface loginService = ServiceAuthGenerator.createService(EndpointInterface.class);
Call<GR> call = loginService.getroutedriver();
call.enqueue(new Callback<GR>() {
@Override
public void onResponse(Response<GR> response , Retrofit retrofit)
{
JSONArray jsonArray_GR = response.body().getRoutes();
blockingQueue.add(jsonArray_GR);
}
@Override
public void onFailure(Throwable t) {
}
});
return blockingQueue;
}
You can then synchronously wait for your result in your calling method like this:
BlockingQueue<JSONArray> result = RequestGR(42,42);
JSONArray value = result.take(); // this will block your thread
I would highly suggest reading up on a framework like rxJava though.
这篇关于如何从函数onResponse of Retrofit返回值?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!