我正在开发一个从api下载一系列字符串的应用程序，然后将它们放在一个数组中，以便可以从自动完成的textview字段调用它们。我无法下载阵列。该数组只是["String", "String" ... etc]我使用ASyncTask来调用api并下载json，但我无法弄清楚如何正确下载它...感谢您的时间......
MapFragment.java
package com.horizonservers.horizon;
import android.app.ProgressDialog;
import android.content.Context;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.reflect.Array;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.jar.Attributes;
/**
* A simple {@link Fragment} subclass.
* Activities that contain this fragment must implement the
* {@link MapFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {@link MapFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class MapFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private TextView test2;
AutoCompleteTextView textView;
ArrayList<String> Maps = new ArrayList<String>();
private OnFragmentInteractionListener mListener;
public MapFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment MapFragment.
*/
// TODO: Rename and change types and number of parameters
public static MapFragment newInstance(String param1, String param2) {
MapFragment fragment = new MapFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_map, container, false);
new PostDataTask().execute("https://www.horizonservers.net/api/mentions/maps?q=surf_&c=map");
textView = (AutoCompleteTextView) v.findViewById(R.id.map_list);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_dropdown_item_1line, Maps);
textView.setThreshold(3);
textView.setAdapter(adapter);
test2 = (TextView) v.findViewById(R.id.testMap);
return v;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
class PostDataTask extends AsyncTask<String, Void, String> {
ProgressDialog progressDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... params) {
try {
return postData(params[0]);
} catch (IOException ex) {
return "Network error !";
} catch (JSONException ex) {
return "Data Invalid !";
}
}
@Override
protected void onPostExecute(String result) {
try {
JSONArray jsonArray = new JSONArray(result);
for(int i = 0; i < jsonArray.length(); i++){
final JSONArray e = jsonArray.getJSONArray(i);
String name = e.toString();
Maps.add(name);
}
test2.setText(Maps.toString());
Toast.makeText(getActivity(), "Success", Toast.LENGTH_SHORT).show();
} catch (JSONException e) {
Log.e("Horizon", "unexpected JSON exception", e);
// Toast.makeText(getActivity(), "Failed to load maps.", Toast.LENGTH_SHORT).show();
}
super.onPostExecute(result);
if (progressDialog != null) {
progressDialog.dismiss();
}
}
private String postData(String urlPath) throws IOException, JSONException {
StringBuilder result = new StringBuilder();
BufferedWriter bufferedWriter = null;
BufferedReader bufferedReader = null;
try {
//Create data to send to server
JSONObject dataToSend = new JSONObject();
//Initialize and config request, then connect to server.
URL url = new URL(urlPath);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setReadTimeout(10000 /* milliseconds */);
urlConnection.setConnectTimeout(10000 /* milliseconds */);
urlConnection.setRequestMethod("POST");
urlConnection.setDoOutput(true); //enable output (body data)
urlConnection.setRequestProperty("Content-Type", "application/json");// set header
urlConnection.connect();
//Write data into server
OutputStream outputStream = urlConnection.getOutputStream();
bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
bufferedWriter.write(dataToSend.toString());
bufferedWriter.flush();
//Read data response from server
InputStream inputStream = urlConnection.getInputStream();
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = bufferedReader.readLine()) != null) {
result.append(line).append("&");
}
} finally {
if (bufferedReader != null) {
bufferedReader.close();
}
if (bufferedWriter != null) {
bufferedWriter.close();
}
}
return result.toString();
}
}
}
实际上调用JSON的部分是OnPostExecute，它是
@Override
protected void onPostExecute(String result) {
try {
JSONArray jsonArray = new JSONArray(result);
for(int i = 0; i < jsonArray.length(); i++){
final JSONArray e = jsonArray.getJSONArray(i);
String name = e.toString();
Maps.add(name);
}
test2.setText(Maps.toString());
Toast.makeText(getActivity(), "Success", Toast.LENGTH_SHORT).show();
} catch (JSONException e) {
Log.e("Horizon", "unexpected JSON exception", e);
// Toast.makeText(getActivity(), "Failed to load maps.", Toast.LENGTH_SHORT).show();
}
super.onPostExecute(result);
if (progressDialog != null) {
progressDialog.dismiss();
}
}
另外应该注意的是，这个数组没有对象，只有字符串，我想我遇到的问题是设置为textview 现在只是为了让我看到它有下载。我尝试将其转换为字符串，但我得到org.json.JSONException: Value Network of type java.lang.String cannot be converted to JSONArray。再次感谢您的时间。
答案 0 :(得分：0)
使用此功能连接到网络服务器
private HttpURLConnection connection;
private URL url = null;
public void connect()
{
try {
url = new URL(SERVER_ADDRESS);
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestMethod("POST");
connection.connect();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
然后使用此函数从那里获取字符串
public String getStringFromServer() {
InputStream input;
StringBuilder result;
String line,JSONRESPOND="";
BufferedReader reader;
try {
input = this.connection.getInputStream();
reader= new BufferedReader(new InputStreamReader(input));
result= new StringBuilder();
while ((line=reader.readLine())!=null)
{
result.append(line);
}
JSONRESPOND = ""+result.toString();
} catch (IOException e) {
return null;
}
return JSONRESPOND;
}
终于搞定了
connect();
String yourJSON = getStringFromServer();
JSONArray yourArray = new JSONArray(yourJSON);
您可以使用此代码段解析此数组
ArrayList<String> yourParsedStrings = new ArrayList<>();
for(int i =0; i<yourArray.length();i++){
yourParsedStrings.add(yourArray.getString(i));
}