本文介绍了Android/Java:如何在方法中延迟返回的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想构建一个 Utils 类来简化 Volley 调用,如下所示:
I want to build a Utils class to make Volley calls simpler, like this:
Utils.java:
Utils.java:
public class Utils {
static JsonObjectRequest mJsonObjectRequest;
protected static boolean busy = true;
public static JSONObject makeJsonObjectRequest(Context context, int method, String url){
final JSONObject[] jsonObject = new JSONObject[1];
mJsonObjectRequest = new JsonObjectRequest
(method, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
jsonObject[0] = response;
busy = false;
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// TODO Auto-generated method stub
try {
jsonObject[0] = new JSONObject(error.toString());
} catch (JSONException e) {
e.printStackTrace();
}
busy = false;
}
});
// Access the RequestQueue through your singleton class.
VolleySingleton.getInstance(context).addToRequestQueue(mJsonObjectRequest);
while (true) {
if (!busy) break;
}
return jsonObject[0];
}
}
MainActivity.java:
MainActivity.java:
JSONObject jsonObject = Utils.makeJsonObjectRequest(this, Request.Method.GET, url);
mTxtDisplay.setText("Response: " + jsonObject.toString());
当应用程序运行时,jsonObject 始终为空.我想问一下我是否可以延迟在 makeJsonObjectRequest 中返回 jsonObject[0] 直到 onResponse 被调用.我可以这样做吗?.
When app runs, jsonObject always null. I want to ask if I can delay return jsonObject[0] inside makeJsonObjectRequest until onResponse called. Can I do that and how?.
推荐答案
我创建了这个并像下面这样管理请看,希望对你有用
I created this and managed like the following way please have a look, hope it will be useful to you
public class APIManager {
public static void createRequest(Context c, String requestTag,
String endPoint, List<NameValuePair> params,
final OnRequestCompletedListener listener,
TransParentProgressDialog pd) {
ServerDetails serverDetails = new ServerDetails(c, endPoint, params);
JsonObjectRequest request = new JsonObjectRequest(Method.GET,
serverDetails.getQueryUrl(), null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
listener.onRequestCompleted(response);
}
}, getErrorListener(c, pd)) {
};
AppController.getInstance().addToRequestQueue(request, requestTag);
}
public static ErrorListener getErrorListener(final Context c,
final TransParentProgressDialog pd, final TextView tvEmpty,
final String errorText) {
Response.ErrorListener listener = new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
if (pd != null && pd.isShowing()) {
pd.dismiss();
}
if (tvEmpty != null) {
tvEmpty.setText(errorText);
}
MyDialog dialog;
Log.d("volley-error", error.toString());
if (error instanceof TimeoutError) {
dialog = new MyDialog(c, "Server Timeout");
dialog.show();
return;
} else if (error instanceof NoConnectionError) {
dialog = new MyDialog(c, "No Connection or Invalid Url");
dialog.show();
return;
} else if (error instanceof ServerError) {
NetworkResponse response = error.networkResponse;
if (response != null) {
// int statusCode = response.statusCode;
byte[] data = response.data;
if (data != null) {
String str = new String(data);
try {
JSONObject object = new JSONObject(str);
Log.d("error response", object.toString());
if (object.has("errors")) {
JSONArray errors = object
.getJSONArray("errors");
JSONObject errorObject = errors
.getJSONObject(0);
dialog = new MyDialog(c, "Error!",
errorObject.getString("message"));
dialog.show();
} else {
dialog = new MyDialog(c, "Error!",
object.toString());
dialog.show();
}
} catch (JSONException e) {
e.printStackTrace();
dialog = new MyDialog(c, "Error!", "Error");
dialog.show();
}
} else {
dialog = new MyDialog(c, "Server Error");
dialog.show();
}
} else {
dialog = new MyDialog(c, "Server Error");
dialog.show();
}
} else if (error instanceof NetworkError) {
NetworkResponse response = error.networkResponse;
if (response != null) {
// int statusCode = response.statusCode;
byte[] data = response.data;
if (data != null) {
String str = new String(data);
try {
JSONObject object = new JSONObject(str);
Log.d("error response", object.toString());
if (object.has("errors")) {
JSONArray errors = object
.getJSONArray("errors");
JSONObject errorObject = errors
.getJSONObject(0);
dialog = new MyDialog(c, "Error!",
errorObject.getString("message"));
dialog.show();
} else {
dialog = new MyDialog(c, "Error!",
object.toString());
dialog.show();
}
} catch (JSONException e) {
e.printStackTrace();
dialog = new MyDialog(c, "Error!", "Error");
dialog.show();
}
} else {
dialog = new MyDialog(c, "Network Error");
dialog.show();
}
} else {
dialog = new MyDialog(c, "Network Error");
dialog.show();
}
} else if (error instanceof ParseError) {
dialog = new MyDialog(c, "Parse Error");
dialog.show();
} else if (error instanceof AuthFailureError) {
NetworkResponse response = error.networkResponse;
if (response != null) {
// int statusCode = response.statusCode;
byte[] data = response.data;
if (data != null) {
String str = new String(data);
try {
JSONObject object = new JSONObject(str);
Log.d("error response", object.toString());
if (object.has("errors")) {
JSONArray errors = object
.getJSONArray("errors");
JSONObject errorObject = errors
.getJSONObject(0);
dialog = new MyDialog(c, "Error!",
errorObject.getString("message"));
dialog.show();
} else {
dialog = new MyDialog(c, "Error!",
object.toString());
dialog.show();
}
} catch (JSONException e) {
e.printStackTrace();
dialog = new MyDialog(c, "Error!", "Error");
dialog.show();
}
} else {
dialog = new MyDialog(c, "Error!", "Error");
dialog.show();
}
} else {
dialog = new MyDialog(c, "Error connecting server");
dialog.show();
}
}
}
};
return listener;
}
}
请求回调完成的接口是
public interface OnRequestCompletedListener {
public void onRequestCompleted(JSONObject response);
}
这篇关于Android/Java:如何在方法中延迟返回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!