AsyncTask的ListView控件 - JSON的Andr​​oid Studio错误 [英] AsyncTask ListView - JSON android studio error

问题描述

我在Eclipse上开发的应用程序。这是一个简单的应用程序，基本上它只是表明从Java EE服务器的数据。在Eclipse上它精致运行，那么我需要迁移到Android的工作室，复制appilication，同样的事情。但现在的ListView不从服务器加载数据，我不知道为什么。

I'm developing an app on Eclipse. It's a simple app, basically it is just to show data from a Java EE Server. On Eclipse it was running fine, then I needed to migrate to Android Studio, copied the appilication, the same thing. But now the ListView doesn't load with the data from the server, and I have no idea why.

下面是我的AsyncTask类：

Here's my AsyncTask Class:

    package com.tumta.henrique.teste;

    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.Reader;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.util.ArrayList;
    import java.util.List;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;

    import android.os.AsyncTask;

    public class ConsultaEntidades extends AsyncTask<Void, Void, List<String>> {

        private ConsultaConcluidaListener listener;

        private static final String URL_STRING = "http://192.168.0.14:7001/com.henrique.rest/api/v1/status/entidade/";

        public ConsultaEntidades(ConsultaConcluidaListener listener) {
            this.listener = listener;
        }

        @Override
        protected List<String> doInBackground(Void... arg0) {
            try {
                String resultado = ConsultaServidor();
                return InterpretaResultado(resultado);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return null;
        }

        private List<String> InterpretaResultado(String resultado) throws JSONException {
            JSONObject object = new JSONObject(resultado);
            JSONArray jsonArray = object.getJSONArray("entidade");
            List<String> listaNomes = new ArrayList<String>();
            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject jsonWaether = jsonArray.getJSONObject(i);
                //int id = jsonWaether.getInt("ent_id");
                String nome = jsonWaether.getString("ent_nome");
                listaNomes.add(i, nome);
            }

            return listaNomes;
        }

        private String ConsultaServidor() throws IOException {
            InputStream is = null;

            try {
                URL url = new URL(URL_STRING);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setConnectTimeout(10000);
                conn.setReadTimeout(15000);
                conn.setRequestMethod("GET");
                conn.setDoInput(true);
                conn.connect();
                conn.getResponseCode();

                is = conn.getInputStream();

                Reader reader = null;
                reader = new InputStreamReader(is);
                char[] buffer = new char[2048];
                reader.read(buffer);
                return new String(buffer);
            } finally {
                if (is != null) {
                    is.close();
                }
            }
        }

        @Override
        protected void onPostExecute(List<String> result) {
            listener.onConsultaConcluida(result);
            super.onPostExecute(result);
        }

        public interface ConsultaConcluidaListener {
            void onConsultaConcluida(List<String> result);
        }
    }

我的片段：

package com.tumta.henrique.teste;


import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import com.tumta.henrique.teste.ConsultaEntidades.*;
import java.util.List;


/**
 * A simple {@link Fragment} subclass.
 */
public class EntidadeFragment extends Fragment implements ConsultaConcluidaListener {

    private static final String ARG_SECTION_NUMBER = "section_number";

    public EntidadeFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_entidade, container, false);
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
    }

    public static EntidadeFragment newInstance(int sectionNumber){
        EntidadeFragment frag = new EntidadeFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        frag.setArguments(args);
        return frag;
    }

    @Override
    public void onConsultaConcluida(List<String> result) {
        ListView listaEntidades = (ListView) getView().findViewById(R.id.listaentidades);
        ArrayAdapter arrayAdapter = new ArrayAdapter<>(getView().getContext(),android.R.layout.simple_list_item_1, result);
        listaEntidades.setAdapter(arrayAdapter);
    }
}

我MainActivity：

My MainActivity:

package com.tumta.henrique.teste;

import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import com.tumta.henrique.teste.EntidadeFragment;


public class MainActivity extends ActionBarActivity
        implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    /**
     * Fragment managing the behaviors, interactions and presentation of the navigation drawer.
     */
    private NavigationDrawerFragment mNavigationDrawerFragment;

    /**
     * Used to store the last screen title. For use in {@link #restoreActionBar()}.
     */
    private CharSequence mTitle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mNavigationDrawerFragment = (NavigationDrawerFragment)
                getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the drawer.
        mNavigationDrawerFragment.setUp(
                R.id.navigation_drawer,
                (DrawerLayout) findViewById(R.id.drawer_layout));
    }

    @Override
    public void onNavigationDrawerItemSelected(int position) {
        // update the main content by replacing fragments
        FragmentManager fragmentManager = getSupportFragmentManager();
        switch(position + 1){
            case 1:
                fragmentManager.beginTransaction()
                        .replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
                        .commit();
            break;
            case 2:
                fragmentManager.beginTransaction()
                        .replace(R.id.container, EntidadeFragment.newInstance(position + 1))
                        .commit();
                break;

        }
        //fragmentManager.beginTransaction()
        //        .replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
        //        .commit();
    }

    public void onSectionAttached(int number) {
        switch (number) {
            case 1:
                mTitle = getString(R.string.title_section1);
                break;
            case 2:
                mTitle = "Entidades";
                break;
            case 3:
                mTitle = getString(R.string.title_section3);
                break;
        }
    }

    public void restoreActionBar() {
        ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle(mTitle);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        if (!mNavigationDrawerFragment.isDrawerOpen()) {
            // Only show items in the action bar relevant to this screen
            // if the drawer is not showing. Otherwise, let the drawer
            // decide what to show in the action bar.
            getMenuInflater().inflate(R.menu.main, menu);
            restoreActionBar();
            return true;
        }
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            ((MainActivity) activity).onSectionAttached(
                    getArguments().getInt(ARG_SECTION_NUMBER));
        }
    }

}

我的清单文件：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.tumta.henrique.teste" >

    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

所以，再一次：这是工作的罚款，当我用Eclipse的，现在我使用Android工作室它没有得到数据形成服务器

So again: It was working fine when I used Eclipse, now that I'M using Android Studio it doesn't get the data form the Server.

推荐答案

问题是，我忘了打电话给我上的 onCreateView 类的片段。感谢的！

The problem was that I forgot to call my class on the onCreateView on the Fragment. Thank's!

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