Volley framework: custom request request and response processing method
Volley framework: Custom request and response processing method exploration
Volley is a widely used network communication library in Android. Its flexible and easy -to -use characteristics make it the first choice for developers.In some special circumstances, we may need to customize Volley's requests and response processing methods to meet specific needs.This article will discuss how to customize these methods and provide some Java code examples.
Volley's core concept is the request queue, which is responsible for managing all network requests.We can define our own request type by customizing the Request class.The following is an example of a simple custom request class:
public class CustomRequest<T> extends Request<T> {
private final Gson gson;
private final Class<T> responseClass;
private final Listener<T> listener;
public CustomRequest(int method, String url, Class<T> responseClass, Listener<T> listener,
ErrorListener errorListener) {
super(method, url, errorListener);
this.responseClass = responseClass;
this.listener = listener;
this.gson = new Gson();
}
@Override
protected void deliverResponse(T response) {
listener.onResponse(response);
}
@Override
protected Response<T> parseNetworkResponse(NetworkResponse response) {
try {
String json = new String(res.networkResponse.data, HttpHeaderParser.parseCharset(res.networkResponse.headers));
return Response.success(gson.fromJson(json, responseClass), HttpHeaderParser.parseCacheHeaders(res));
} catch (UnsupportedEncodingException e) {
return Response.error(new ParseError(e));
} catch (JsonSyntaxException e) {
return Response.error(new ParseError(e));
}
}
}
In the above example, we created a custom request claim called CustomRequest.We implement the function of custom requests by inheriting the Request class of the Volley.In the constructive function, we pass the request method, URL address, Class type type of server response, listeners who have responded to successful response, and error monitoring.
We rewritten the DeliverResponse method. In this method, we pass the response of the request to the caller.
In addition, we also rewritten the PARENENETWORKRESPONSE method. In this method, we transform the data response data into the specified class type and package it into the response object of Volley.
When we need to send a custom request, we only need to create the CustomRequest object and add it to the Volley's request queue:
RequestQueue queue = Volley.newRequestQueue(context);
CustomRequest<MyResponse> request = new CustomRequest<>(Method.GET, url, MyResponse.class,
response -> {
// Request successful callback
},
error -> {
// The request fails to call back
});
queue.add(request);
In addition to custom request classes, we can also make special treatment of Volley's response through custom response processing methods.The following is an example:
public class CustomResponse<T> implements Response.Listener<T>, Response.ErrorListener {
@Override
public void onResponse(T response) {
// Response processing logic
}
@Override
public void onErrorResponse(VolleyError error) {
// Error processing logic
}
}
In the above example, we created a custom response processing class called CustomResponse.We handle success response and error responses by implementing Volley's response.listener and Response.errorListener interfaces, respectively.
When we send a request, we only need to pass the CustomResponse object to the monitor parameter in the constructor in CustomRequest:
CustomRequest<MyResponse> request = new CustomRequest<>(Method.GET, url, MyResponse.class,
new CustomResponse<MyResponse>(),
new CustomResponse<MyResponse>());
queue.add(request);
By customizing requests and response processing methods, we can easily expand the function of Volley to meet various specific needs.Whether it is a custom request class or a custom response processing class, Volley's flexibility enables us to easily integrate them into our applications and realize customized network communication functions.
