java - android java主机问题

Question

所以我在网上找到了一些脚本并对其进行了一些修改，但我无法让它工作!这是 AllProjects.java

 package com.main.timelogger;

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.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class AllProjects extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;

// Creating JSON Parser object
JSONParser jParser = new JSONParser();

ArrayList<HashMap<String, String>> projectsList;

// url to get all products list
private static String url_all_products = "http://10.0.2.2/test/getAllProjects.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PROJECTS = "projects";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";

// products JSONArray
JSONArray products = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_project);

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

    // Loading products in Background Thread
    new LoadAllProjects().execute();

    // Get listview
    ListView lv = getListView();

    // on selecting single product
    // launching Edit Product Screen
    lv.setOnItemClickListener(new OnItemClickListener() {

        public void onItemClick(AdapterView<?> parent, View view,int position, long id) {
            // getting values from selected ListItem
            String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                    .toString();

            // Starting new intent
            Intent in = new Intent(getApplicationContext(),
                    EditProject.class);
            // sending pid to next activity
            in.putExtra(TAG_PID, pid);

            // starting new activity and expecting some response back
            startActivityForResult(in, 100);
        }
    });

}

// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // if result code 100
    if (resultCode == 100) {
        // if result code 100 is received 
        // means user edited/deleted product
        // reload this screen again
        Intent intent = getIntent();
        finish();
        startActivity(intent);
    }

}

/**
 * Background Async Task to Load all product by making HTTP Request
 * */
class LoadAllProjects extends AsyncTask<String, String, String> {

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

    /**
     * getting All products 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_products, "GET", params);

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

        try {
            // Checking for SUCCESS TAG
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // products found
                // Getting Array of Products
                products = json.getJSONArray(TAG_PROJECTS);

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

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

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

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

                    // adding HashList to ArrayList
                    projectsList.add(map);
                }
            } else {
                // no products found
                // Launch Add New product Activity
                Intent i = new Intent(getApplicationContext(),
                        NewProject.class);
                // Closing all previous activities
                i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
            }
        } 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(
                        AllProjects.this, projectsList,
                        R.layout.list_item, new String[] { TAG_PID,
                                TAG_NAME},
                        new int[] { R.id.pid, R.id.name });
                // updating listview
                setListAdapter(adapter);
            }
        });

    }

}

这是 JSONParser.java

    package com.main.timelogger;

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 method
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) {
        Log.e("Error","1o catch");
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        Log.e("Error","2o catch");
        e.printStackTrace();
    } catch (IOException e) {
        Log.e("Error","3o catch");
        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;

}
}

这是日志

09-12 02:25:27.353: I/ActivityThread(7470): queueIdle
09-12 02:25:27.353: V/ActivityThread(7470): Reporting idle of ActivityRecord{4a3fd360 token=android.os.BinderProxy@4a3fce38 {com.main.timelogger/com.main.timelogger.AllProjects}} finished=false
09-12 02:25:27.353: W/ActivityNative(7470): send ACTIVITY_IDLE_TRANSACTION
09-12 02:25:48.343: E/Error(7470): 3o catch
09-12 02:25:48.353: W/System.err(7470): java.net.SocketException: The operation timed out
09-12 02:25:48.353: W/System.err(7470):     at org.apache.harmony.luni.platform.OSNetworkSystem.connectStreamWithTimeoutSocketImpl(Native Method)
09-12 02:25:48.353: W/System.err(7470):     at org.apache.harmony.luni.platform.OSNetworkSystem.connect(OSNetworkSystem.java:115)
09-12 02:25:48.353: W/System.err(7470):     at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:244)
09-12 02:25:48.353: W/System.err(7470):     at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:533)
09-12 02:25:48.353: W/System.err(7470):     at java.net.Socket.connect(Socket.java:1074)
09-12 02:25:48.353: W/System.err(7470):     at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
09-12 02:25:48.353: W/System.err(7470):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:153)
09-12 02:25:48.363: W/System.err(7470):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
09-12 02:25:48.363: W/System.err(7470):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
09-12 02:25:48.363: W/System.err(7470):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:348)
09-12 02:25:48.363: W/System.err(7470):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
09-12 02:25:48.363: W/System.err(7470):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
09-12 02:25:48.363: W/System.err(7470):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
09-12 02:25:48.373: W/System.err(7470):     at com.main.timelogger.JSONParser.makeHttpRequest(JSONParser.java:62)
09-12 02:25:48.373: W/System.err(7470):     at com.main.timelogger.AllProjects$LoadAllProjects.doInBackground(AllProjects.java:125)
09-12 02:25:48.373: W/System.err(7470):     at com.main.timelogger.AllProjects$LoadAllProjects.doInBackground(AllProjects.java:1)
09-12 02:25:48.373: W/System.err(7470):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
09-12 02:25:48.373: W/System.err(7470):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
09-12 02:25:48.373: W/System.err(7470):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
09-12 02:25:48.373: W/System.err(7470):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
09-12 02:25:48.373: W/System.err(7470):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
09-12 02:25:48.373: W/System.err(7470):     at java.lang.Thread.run(Thread.java:1096)
09-12 02:25:48.373: E/Buffer Error(7470): Error converting result java.lang.NullPointerException
09-12 02:25:48.373: E/JSON Parser(7470): Error parsing data org.json.JSONException: End of input at character 0 of 
09-12 02:25:48.383: W/dalvikvm(7470): threadid=8: thread exiting with uncaught exception (group=0x400207d8)
09-12 02:25:48.393: E/AndroidRuntime(7470): FATAL EXCEPTION: AsyncTask #1
09-12 02:25:48.393: E/AndroidRuntime(7470): java.lang.RuntimeException: An error occured while executing doInBackground()
09-12 02:25:48.393: E/AndroidRuntime(7470):     at android.os.AsyncTask$3.done(AsyncTask.java:200)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.lang.Thread.run(Thread.java:1096)
09-12 02:25:48.393: E/AndroidRuntime(7470): Caused by: java.lang.NullPointerException
09-12 02:25:48.393: E/AndroidRuntime(7470):     at com.main.timelogger.AllProjects$LoadAllProjects.doInBackground(AllProjects.java:128)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at com.main.timelogger.AllProjects$LoadAllProjects.doInBackground(AllProjects.java:1)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
09-12 02:25:48.393: E/AndroidRuntime(7470):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
09-12 02:25:48.393: E/AndroidRuntime(7470):     ... 4 more
09-12 02:25:48.693: E/WindowManager(7470): Activity com.main.timelogger.AllProjects has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a40c720 that was originally added here
09-12 02:25:48.693: E/WindowManager(7470): android.view.WindowLeaked: Activity com.main.timelogger.AllProjects has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a40c720 that was originally added here
09-12 02:25:48.693: E/WindowManager(7470):  at android.view.ViewRoot.<init>(ViewRoot.java:247)
09-12 02:25:48.693: E/WindowManager(7470):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
09-12 02:25:48.693: E/WindowManager(7470):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
09-12 02:25:48.693: E/WindowManager(7470):  at android.view.Window$LocalWindowManager.addView(Window.java:424)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.Dialog.show(Dialog.java:241)
09-12 02:25:48.693: E/WindowManager(7470):  at com.main.timelogger.AllProjects$LoadAllProjects.onPreExecute(AllProjects.java:115)
09-12 02:25:48.693: E/WindowManager(7470):  at android.os.AsyncTask.execute(AsyncTask.java:391)
09-12 02:25:48.693: E/WindowManager(7470):  at com.main.timelogger.AllProjects.onCreate(AllProjects.java:57)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2633)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2685)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.ActivityThread.access$2300(ActivityThread.java:126)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2038)
09-12 02:25:48.693: E/WindowManager(7470):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-12 02:25:48.693: E/WindowManager(7470):  at android.os.Looper.loop(Looper.java:123)
09-12 02:25:48.693: E/WindowManager(7470):  at android.app.ActivityThread.main(ActivityThread.java:4633)
09-12 02:25:48.693: E/WindowManager(7470):  at java.lang.reflect.Method.invokeNative(Native Method)
09-12 02:25:48.693: E/WindowManager(7470):  at java.lang.reflect.Method.invoke(Method.java:521)
09-12 02:25:48.693: E/WindowManager(7470):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
09-12 02:25:48.693: E/WindowManager(7470):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
09-12 02:25:48.693: E/WindowManager(7470):  at dalvik.system.NativeStart.main(Native Method)

服务器上的文件没有问题，也没有任何防火墙..我不明白问题出在哪里，如果可以的话请帮助我:)

Answer 1

 Caused by: java.lang.NullPointerException
09-12 02:25:48.393: E/AndroidRuntime(7470):     at com.main.timelogger.AllProjects$LoadAllProjects.doInBackground(AllProjects.java:128)

您的问题是:AllProjects.java:128，您必须验证 doInBackground()

中的变量