Question

我的PostgreSql数据库中有一个列表，我希望它出现在我的3个viewPager片段中的一个中，这是我的应用程序的mainActivity代码：

 package info.androidhive.tabsswipe;

 import info.androidhive.tabsswipe.adapter.TabsPagerAdapter;
 import android.app.ActionBar;
 import android.app.ActionBar.Tab;
 import android.app.FragmentTransaction;
 import android.os.Bundle;
 import android.support.v4.app.FragmentActivity;
 import android.support.v4.view.ViewPager;

 public class MainActivity extends FragmentActivity implements ActionBar.TabListener {

    private ViewPager viewPager;
    private TabsPagerAdapter mAdapter;
    private ActionBar actionBar;
    // Tab titles
    private String[] tabs = { "Top Rated", "Games", "Movies" };

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

        // Initilization
        viewPager = (ViewPager) findViewById(R.id.pager);
        actionBar = getActionBar();
        mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

        viewPager.setAdapter(mAdapter);
        actionBar.setHomeButtonEnabled(false);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);        

        // Adding Tabs
        for (String tab_name : tabs) {
            actionBar.addTab(actionBar.newTab().setText(tab_name)
                    .setTabListener(this));
        }

        /**
         * on swiping the viewpager make respective tab selected
         * */
        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                // on changing the page
                // make respected tab selected
                actionBar.setSelectedNavigationItem(position);
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
            }
        });
    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // on tab selected
        // show respected fragment view
        viewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    }

}

这是ListFragment代码：

package info.androidhive.tabsswipe;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.support.v4.app.ListFragment;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;

public class TopRatedFragment extends ListFragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View myFragmentView = inflater.inflate(R.layout.fragment_top_rated,
                container, false);

        return myFragmentView;

    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

    }
    ArrayList<HashMap<String, String>> interventionsList;
    // Progress Dialog
    private ProgressDialog pDialog;
 // url to get all interventions list
    private static String url_all_interventions = "http://10.0.2.2/Scripts/liste_interventions.php";
    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

     // interventions JSONArray
    JSONArray interventions = null;
    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        this.getListView().setTextFilterEnabled(true);

        // Hashmap for ListView
        interventionsList = new ArrayList<HashMap<String, String>>();

        // Loading interventions in Background Thread
        new LoadAllInterventions().execute();
    }
    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class LoadAllInterventions extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(getActivity());
            pDialog.setMessage("Loading interventions. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All interventions from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_interventions, "GET", params);

            // Check your log cat for JSON reponse
            Log.d("All Interventions: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt("success");
                Log.d("success" , json.toString());
                if (success == 1) {
                    // interventions found
                    // Getting Array of interventions
                    interventions = json.getJSONArray("interventions");

                    // looping through All interventions
                    for (int i = 0; i < interventions.length(); i++) {
                        JSONObject c = interventions.getJSONObject(i);

                        // Storing each json item in variable
                        String  id = c.getString("id");
                        String name = c.getString("name");

                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        map.put("Int_id",   id);
                        map.put("Int_name", name);

                        // adding HashList to ArrayList
                        interventionsList.add(map);
                    }
                }
            } catch (JSONException e) {e.printStackTrace();}
            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all products
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            getActivity(), interventionsList,
                            R.layout.list_item, new String[] { "Int_id",
                                    "Int_name"},
                            new int[] { R.id.pid, R.id.name });
                    // updating listview
                    setListAdapter(adapter);
                    Log.e("LIST", "setListAdapter is done");
                }
            });

        }

    }
    public void runOnUiThread(Runnable runnable) {
        // TODO Auto-generated method stub

    }

}

这是TabsPagerAdapter类的代码：

package info.androidhive.tabsswipe.adapter;

import info.androidhive.tabsswipe.GamesFragment;
import info.androidhive.tabsswipe.MoviesFragment;
import info.androidhive.tabsswipe.TopRatedFragment;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

public class TabsPagerAdapter extends FragmentPagerAdapter {

    public TabsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int index) {

        switch (index) {
        case 0:
            // Top Rated fragment activity
            return new TopRatedFragment();
        case 1:
            // Games fragment activity
            return new GamesFragment();
        case 2:
            // Movies fragment activity
            return new MoviesFragment();
        }

        return null;
    }

    @Override
    public int getCount() {
        // get item count - equal to number of tabs
        return 3;
    }

}

这是JSONParser类的代码：

package info.androidhive.tabsswipe;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    // function get json from url
    // by making HTTP POST or GET mehtod
    public JSONObject makeHttpRequest(String url, String method,
            List<NameValuePair> params) {

        // Making HTTP request
        try {

            // check for request method
            if(method == "POST"){
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            }else if(method == "GET"){
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }           

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

这是ListFragment Layout的代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#99E7E5" >
<ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
</RelativeLayout>

这是与postgresql数据库通信的php文件：

<?php
$hostname_localhost ='localhost';
$port_localhost =5432;
$database_localhost ='techmobi';
$username_localhost ='openpg';
$password_localhost ='openpgpwd';
$localhost = "host='$hostname_localhost' port='$port_localhost' dbname='$database_localhost' user='$username_localhost' password='$password_localhost'";
$connexion =pg_connect($localhost) or die ("Erreur de connexion ".pg_last_error());
$query_search = "select id,name from crm_helpdesk";
$query_exec = pg_query($query_search) or die(pg_error());


$output = array();
while($rows=pg_fetch_assoc($query_exec))
{
$output[]=$rows;
}
echo json_encode($output);
?>

运行后应用程序关闭以及logCat中显示的内容： JSONParser error

请任何帮助!!!

Answer 1

日志文件顶部的错误告诉您完全问题：

您的JSON字符串是两个JSON对象的JSON数组。但是您试图将其解析为JSON对象。

更改此行：

   // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);

要成为这样：

   // try parse the string to a JSON array
    try {
        jArr = new JSONArray(json);

其中jArr声明为JSONArray类型。

视图寻呼机内的ListFragment

1 个答案: