使用回调接口实现AsyncTask - 在单个回调接口中处理多个呼叫响应
问题描述:
在我的Android应用程序中,我从一个Activity进行多个API调用。我正在使用以下方法:在Activity中实现接口并从Async类调用该接口函数。使用回调接口实现AsyncTask - 在单个回调接口中处理多个呼叫响应
public interface AsyncResponse {
public void processFinish(JSONObject sb);
}
public class FetchData extends AsyncTask<String, Integer, JSONObject> {
HttpURLConnection urlConnection;
String url;
String method;
String payload = null;
AsyncResponse delegate = null;
public FetchData(AsyncResponse delegate, String url, String method) {
this.delegate = delegate;
this.url = url;
this.method = method;
}
public FetchData(AsyncResponse delegate, String url, String method, JSONObject payload) {
this(delegate, url, method);
this.payload = payload.toString();
}
@Override
protected JSONObject doInBackground(String... args) {
BufferedReader reader = null;
try {
URL url = new URL(this.url);
// Open HTTP connection
urlConnection = (HttpURLConnection) url.openConnection();
// HTTP method GET/POST/PUT/DELETE
urlConnection.setRequestMethod(this.method);
// handle issues
int statusCode = urlConnection.getResponseCode();
// Get the response
InputStream inputStream = urlConnection.getInputStream();
if(inputStream == null) {
// Nothing to do
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
String inputLine = null;
StringBuffer response = new StringBuffer();
while ((inputLine = reader.readLine()) != null) {
response.append(inputLine + "\n");
}
return new JSONObject(response.toString());
} catch(Exception e) {
try {
// Return error response
} catch(Exception e1) {
System.out.println(e1);
return null;
}
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e("PlaceholderFragment", "Error closing stream", e);
}
}
}
}
@Override
protected void onPostExecute(JSONObject result) {
super.onPostExecute(result);
this.delegate.processFinish(result);
}
}
public class AsyncTasks extends AppCompatActivity implements AsyncResponse {
TextView view = null;
int a = 1;
Utility utility = Utility.getInstance();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_async_tasks);
new FetchData(this, "<url 1>", "GET").executeOnExecutor(THREAD_POOL_EXECUTOR);
new FetchData(this, "<url 2>", "GET").executeOnExecutor(THREAD_POOL_EXECUTOR);
}
@Override
public void processFinish(JSONObject data) {
utility.showDialog(this, data.toString());
}
}
这里如何处理processFinish()接口函数第二GET调用的响应?什么是最好的方法?
答
public interface AsyncResponse {
//Add requestCode to identify request.
public void processFinish(JSONObject sb, int requestCode);
}
public class FetchData extends AsyncTask<String, Integer, JSONObject> {
HttpURLConnection urlConnection;
String url;
String method;
String payload = null;
AsyncResponse delegate = null;
int requestCode;
public FetchData(String url, String method) {
this(url, method, null);
}
public FetchData(String url, String method, JSONObject payload) {
this.url = url;
this.method = method;
if(payload!=null){
this.payload = payload.toString();
}
}
//You can set AsyncResponse and RequestCode in constructor also.
public FetchData setListener(AsyncResponse asyncResponse, int requestCode){
this.delegate = asyncResponse;
this.requestCode = requestCode;
return this;
}
@Override
protected JSONObject doInBackground(String... args) {
....
}
@Override
protected void onPostExecute(JSONObject result) {
super.onPostExecute(result);
if(delegate!=null){
//post result with given requestCode
this.delegate.processFinish(result, requestCode);
}
}
}
public class AsyncTasks extends AppCompatActivity implements AsyncResponse {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_async_tasks);
// Make first call with request code as 1
new FetchData("<url 1>", "GET").setListener(this, 1).executeOnExecutor(THREAD_POOL_EXECUTOR);
// Make second call with request code as 2
new FetchData("<url 2>", "GET").setListener(this, 2).executeOnExecutor(THREAD_POOL_EXECUTOR);
}
@Override
public void processFinish(JSONObject data, int requestCode) {
switch(requestCode){
case 1:
//perform task on 1st call finish
break;
case 2:
utility.showDialog(this, data.toString());
//perform task on 2nd call finish
break;
}
}
}
如果两个网址都不同,那么只需添加条件以匹配所提供的url并读取响应。 –
可能有相同的URL的机会。有什么办法通过设置标签或其他方式来识别呼叫吗?请提供示例代码。 – Sivakumar
我会为您的FetchData的构造函数添加一些请求ID,并将其传回processFinish以区分这两个请求。 – Viacheslav