Tôi gặp vấn đề tương tự và phát triển giải pháp toàn cầu để xử lý (và thiếu chức năng của Volley), tôi đăng nó lên một chủ đề khác nhưng tôi nghĩ nó có thể giúp nhiều người đang tìm kiếm giải pháp cho vấn đề của bạn.
/**
* Created by laurentmeyer on 25/07/15.
*/
public class GenericRequest<T> extends JsonRequest<T> {
private final Gson gson = new Gson();
private final Class<T> clazz;
private final Map<String, String> headers;
// Used for request which do not return anything from the server
private boolean muteRequest = false;
/**
* Basically, this is the constructor which is called by the others.
* It allows you to send an object of type A to the server and expect a JSON representing a object of type B.
* The problem with the #JsonObjectRequest is that you expect a JSON at the end.
* We can do better than that, we can directly receive our POJO.
* That's what this class does.
*
* @param method: HTTP Method
* @param classtype: Classtype to parse the JSON coming from the server
* @param url: url to be called
* @param requestBody: The body being sent
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
* @param headers: Added headers
*/
private GenericRequest(int method, Class<T> classtype, String url, String requestBody,
Response.Listener<T> listener, Response.ErrorListener errorListener, Map<String, String> headers) {
super(method, url, requestBody, listener,
errorListener);
clazz = classtype;
this.headers = headers;
configureRequest();
}
/**
* Method to be called if you want to send some objects to your server via body in JSON of the request (with headers and not muted)
*
* @param method: HTTP Method
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param toBeSent: Object which will be transformed in JSON via Gson and sent to the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
* @param headers: Added headers
*/
public GenericRequest(int method, String url, Class<T> classtype, Object toBeSent,
Response.Listener<T> listener, Response.ErrorListener errorListener, Map<String, String> headers) {
this(method, classtype, url, new Gson().toJson(toBeSent), listener,
errorListener, headers);
}
/**
* Method to be called if you want to send some objects to your server via body in JSON of the request (without header and not muted)
*
* @param method: HTTP Method
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param toBeSent: Object which will be transformed in JSON via Gson and sent to the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
*/
public GenericRequest(int method, String url, Class<T> classtype, Object toBeSent,
Response.Listener<T> listener, Response.ErrorListener errorListener) {
this(method, classtype, url, new Gson().toJson(toBeSent), listener,
errorListener, new HashMap<String, String>());
}
/**
* Method to be called if you want to send something to the server but not with a JSON, just with a defined String (without header and not muted)
*
* @param method: HTTP Method
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param requestBody: String to be sent to the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
*/
public GenericRequest(int method, String url, Class<T> classtype, String requestBody,
Response.Listener<T> listener, Response.ErrorListener errorListener) {
this(method, classtype, url, requestBody, listener,
errorListener, new HashMap<String, String>());
}
/**
* Method to be called if you want to GET something from the server and receive the POJO directly after the call (no JSON). (Without header)
*
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
*/
public GenericRequest(String url, Class<T> classtype, Response.Listener<T> listener, Response.ErrorListener errorListener) {
this(Request.Method.GET, url, classtype, "", listener, errorListener);
}
/**
* Method to be called if you want to GET something from the server and receive the POJO directly after the call (no JSON). (With headers)
*
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
* @param headers: Added headers
*/
public GenericRequest(String url, Class<T> classtype, Response.Listener<T> listener, Response.ErrorListener errorListener, Map<String, String> headers) {
this(Request.Method.GET, classtype, url, "", listener, errorListener, headers);
}
/**
* Method to be called if you want to send some objects to your server via body in JSON of the request (with headers and muted)
*
* @param method: HTTP Method
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param toBeSent: Object which will be transformed in JSON via Gson and sent to the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
* @param headers: Added headers
* @param mute: Muted (put it to true, to make sense)
*/
public GenericRequest(int method, String url, Class<T> classtype, Object toBeSent,
Response.Listener<T> listener, Response.ErrorListener errorListener, Map<String, String> headers, boolean mute) {
this(method, classtype, url, new Gson().toJson(toBeSent), listener,
errorListener, headers);
this.muteRequest = mute;
}
/**
* Method to be called if you want to send some objects to your server via body in JSON of the request (without header and muted)
*
* @param method: HTTP Method
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param toBeSent: Object which will be transformed in JSON via Gson and sent to the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
* @param mute: Muted (put it to true, to make sense)
*/
public GenericRequest(int method, String url, Class<T> classtype, Object toBeSent,
Response.Listener<T> listener, Response.ErrorListener errorListener, boolean mute) {
this(method, classtype, url, new Gson().toJson(toBeSent), listener,
errorListener, new HashMap<String, String>());
this.muteRequest = mute;
}
/**
* Method to be called if you want to send something to the server but not with a JSON, just with a defined String (without header and not muted)
*
* @param method: HTTP Method
* @param url: URL to be called
* @param classtype: Classtype to parse the JSON returned from the server
* @param requestBody: String to be sent to the server
* @param listener: Listener of the request
* @param errorListener: Error handler of the request
* @param mute: Muted (put it to true, to make sense)
*/
public GenericRequest(int method, String url, Class<T> classtype, String requestBody,
Response.Listener<T> listener, Response.ErrorListener errorListener, boolean mute) {
this(method, classtype, url, requestBody, listener,
errorListener, new HashMap<String, String>());
this.muteRequest = mute;
}
@Override
protected Response<T> parseNetworkResponse(NetworkResponse response) {
// The magic of the mute request happens here
if (muteRequest) {
if (response.statusCode >= 200 && response.statusCode <= 299) {
// If the status is correct, we return a success but with a null object, because the server didn't return anything
return Response.success(null, HttpHeaderParser.parseCacheHeaders(response));
}
} else {
try {
// If it's not muted; we just need to create our POJO from the returned JSON and handle correctly the errors
String json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
T parsedObject = gson.fromJson(json, clazz);
return Response.success(parsedObject, HttpHeaderParser.parseCacheHeaders(response));
} catch (UnsupportedEncodingException e) {
return Response.error(new ParseError(e));
} catch (JsonSyntaxException e) {
return Response.error(new ParseError(e));
}
}
return null;
}
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
return headers != null ? headers : super.getHeaders();
}
private void configureRequest() {
// Set retry policy
// Add headers, for auth for example
// ...
}
}
Đây là original answer trên thread khác.
đâu Chính xác những gì bạn nhận được 'NullPointerException'? Bên trong Lib hoặc trong mã của bạn? vui lòng thêm StackTrace. – Simulant
@Simulant xin vui lòng xem các chỉnh sửa – coder
Tôi có vấn đề này quá, onError của tôi không bao giờ được gọi là – CQM