我创建了一个从在线MySQL数据库中获取内容的应用程序。 我已经使用了JSON Parser。我的应用程序在模拟器上工作正常但在我的移动设备上却无法获取内容。
这是我的代码，直到现在： AllPapersActivity.java
package com.papershare.bhanu;
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 AllPapersActivity extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> papersList;
// url to get all papers list
private static String url_all_papers = "http://kidessential.esy.es/android_connect_paper/get_all_papers.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_paperS = "papers";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
private static final String TAG_DESCRIPTION = "description";
// papers JSONArray
JSONArray papers = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_papers);
// Hashmap for ListView
papersList = new ArrayList<HashMap<String, String>>();
// Loading papers in Background Thread
new LoadAllpapers().execute();
// Get listview
ListView lv = getListView();
// on seleting single paper
// launching Edit paper Screen
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String description = ((TextView) view.findViewById(R.id.description)).getText()
.toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
WebViewer.class);
// sending pid to next activity
in.putExtra(TAG_DESCRIPTION, description);
// starting new activity and expecting some response back
startActivityForResult(in, 100);
}
});
}
// Response from Edit paper 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 paper
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all paper by making HTTP Request
* */
class LoadAllpapers extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AllPapersActivity.this);
pDialog.setMessage("Loading papers. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All papers 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_papers, "GET", params);
// Check your log cat for JSON reponse
Log.d("All papers: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// papers found
// Getting Array of papers
papers = json.getJSONArray(TAG_paperS);
// looping through All papers
for (int i = 0; i < papers.length(); i++) {
JSONObject c = papers.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
String descrip = c.getString(TAG_DESCRIPTION);
// 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);
map.put(TAG_DESCRIPTION, descrip);
// adding HashList to ArrayList
papersList.add(map);
}
} else {
// no papers found
// Launch Add New paper Activity
Intent i = new Intent(getApplicationContext(),
NewPapersActivity.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 papers
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
AllPapersActivity.this, papersList,
R.layout.list_item,
new String[] { TAG_PID,TAG_NAME, TAG_DESCRIPTION},
new int[] { R.id.pid, R.id.name, R.id.description});
// updating listview
setListAdapter(adapter);
}
});
}
}
}
这是JSONParser.java
package com.papershare.bhanu;
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.equals("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.equals("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;
}
}
正如您所看到的，我在我的hostinger帐户中托管我的php文件，并且还创建了我的MySQL数据库。 这是应用程序在USB调试模式下运行时的logcat。
03-22 16:42:23.268: D/dalvikvm(531): Not late-enabling CheckJNI (already on)
03-22 16:42:23.508: I/dalvikvm(531): Turning on JNI app bug workarounds for target SDK version 8...
03-22 16:42:24.228: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:42:24.238: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:42:24.648: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:42:24.698: D/dalvikvm(531): GC_FOR_ALLOC freed 64K, 2% free 12613K/12867K, paused 261ms
03-22 16:42:24.718: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:42:24.738: I/dalvikvm-heap(531): Grow heap (frag case) to 15.890MB for 3686416-byte allocation
03-22 16:42:24.858: D/dalvikvm(531): GC_CONCURRENT freed 1K, 2% free 16212K/16519K, paused 4ms+14ms
03-22 16:42:25.058: D/dalvikvm(531): GC_FOR_ALLOC freed 0K, 2% free 16212K/16519K, paused 31ms
03-22 16:42:25.118: I/dalvikvm-heap(531): Grow heap (frag case) to 22.140MB for 6554896-byte allocation
03-22 16:42:25.148: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:42:25.199: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:42:25.237: D/dalvikvm(531): GC_CONCURRENT freed 0K, 2% free 22613K/22983K, paused 5ms+5ms
03-22 16:42:25.618: D/(531): HostConnection::get() New Host Connection established 0x17c018, tid 531
03-22 16:42:25.728: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:42:25.738: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:42:26.328: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:42:26.338: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:58:22.478: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:58:22.518: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:58:22.958: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:58:23.117: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 16:58:24.167: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 16:58:24.178: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 17:01:32.008: W/System.err(531): org.apache.http.conn.HttpHostConnectException: Connection to http://10.0.2.2 refused
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:183)
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
03-22 17:01:32.008: W/System.err(531): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
03-22 17:01:32.038: W/System.err(531): at com.papershare.bhanu.JSONParser.makeHttpRequest(JSONParser.java:62)
03-22 17:01:32.048: W/System.err(531): at com.papershare.bhanu.AllPapersActivity$LoadAllpapers.doInBackground(AllPapersActivity.java:128)
03-22 17:01:32.048: W/System.err(531): at com.papershare.bhanu.AllPapersActivity$LoadAllpapers.doInBackground(AllPapersActivity.java:1)
03-22 17:01:32.048: W/System.err(531): at android.os.AsyncTask$2.call(AsyncTask.java:264)
03-22 17:01:32.048: W/System.err(531): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
03-22 17:01:32.058: W/System.err(531): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
03-22 17:01:32.058: W/System.err(531): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
03-22 17:01:32.058: W/System.err(531): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
03-22 17:01:32.058: W/System.err(531): at java.lang.Thread.run(Thread.java:856)
03-22 17:01:32.068: W/System.err(531): Caused by: java.net.ConnectException: failed to connect to /10.0.2.2 (port 80): connect failed: ETIMEDOUT (Connection timed out)
03-22 17:01:32.068: W/System.err(531): at libcore.io.IoBridge.connect(IoBridge.java:114)
03-22 17:01:32.078: W/System.err(531): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
03-22 17:01:32.078: W/System.err(531): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
03-22 17:01:32.078: W/System.err(531): at java.net.Socket.connect(Socket.java:842)
03-22 17:01:32.078: W/System.err(531): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
03-22 17:01:32.078: W/System.err(531): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
03-22 17:01:32.088: W/System.err(531): ... 15 more
03-22 17:01:32.088: W/System.err(531): Caused by: libcore.io.ErrnoException: connect failed: ETIMEDOUT (Connection timed out)
03-22 17:01:32.097: W/System.err(531): at libcore.io.Posix.connect(Native Method)
03-22 17:01:32.097: W/System.err(531): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)
03-22 17:01:32.097: W/System.err(531): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
03-22 17:01:32.097: W/System.err(531): at libcore.io.IoBridge.connect(IoBridge.java:112)
03-22 17:01:32.108: W/System.err(531): ... 20 more
03-22 17:01:32.108: E/Buffer Error(531): Error converting result java.lang.NullPointerException
03-22 17:01:32.108: E/JSON Parser(531): Error parsing data org.json.JSONException: End of input at character 0 of
03-22 17:01:32.117: W/dalvikvm(531): threadid=11: thread exiting with uncaught exception (group=0x409c01f8)
03-22 17:01:32.147: E/AndroidRuntime(531): FATAL EXCEPTION: AsyncTask #1
03-22 17:01:32.147: E/AndroidRuntime(531): java.lang.RuntimeException: An error occured while executing doInBackground()
03-22 17:01:32.147: E/AndroidRuntime(531): at android.os.AsyncTask$3.done(AsyncTask.java:278)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.lang.Thread.run(Thread.java:856)
03-22 17:01:32.147: E/AndroidRuntime(531): Caused by: java.lang.NullPointerException
03-22 17:01:32.147: E/AndroidRuntime(531): at com.papershare.bhanu.AllPapersActivity$LoadAllpapers.doInBackground(AllPapersActivity.java:131)
03-22 17:01:32.147: E/AndroidRuntime(531): at com.papershare.bhanu.AllPapersActivity$LoadAllpapers.doInBackground(AllPapersActivity.java:1)
03-22 17:01:32.147: E/AndroidRuntime(531): at android.os.AsyncTask$2.call(AsyncTask.java:264)
03-22 17:01:32.147: E/AndroidRuntime(531): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
03-22 17:01:32.147: E/AndroidRuntime(531): ... 4 more
03-22 17:01:32.808: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 17:01:32.838: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 17:01:34.098: I/dalvikvm(531): threadid=3: reacting to signal 3
03-22 17:01:34.118: I/dalvikvm(531): Wrote stack traces to '/data/anr/traces.txt'
03-22 17:01:35.828: E/WindowManager(531): Activity com.papershare.bhanu.AllPapersActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41fe6a18 that was originally added here
03-22 17:01:35.828: E/WindowManager(531): android.view.WindowLeaked: Activity com.papershare.bhanu.AllPapersActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41fe6a18 that was originally added here
03-22 17:01:35.828: E/WindowManager(531): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:344)
03-22 17:01:35.828: E/WindowManager(531): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:267)
03-22 17:01:35.828: E/WindowManager(531): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
03-22 17:01:35.828: E/WindowManager(531): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
03-22 17:01:35.828: E/WindowManager(531): at android.view.Window$LocalWindowManager.addView(Window.java:537)
03-22 17:01:35.828: E/WindowManager(531): at android.app.Dialog.show(Dialog.java:278)
03-22 17:01:35.828: E/WindowManager(531): at com.papershare.bhanu.AllPapersActivity$LoadAllpapers.onPreExecute(AllPapersActivity.java:118)
03-22 17:01:35.828: E/WindowManager(531): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:561)
03-22 17:01:35.828: E/WindowManager(531): at android.os.AsyncTask.execute(AsyncTask.java:511)
03-22 17:01:35.828: E/WindowManager(531): at com.papershare.bhanu.AllPapersActivity.onCreate(AllPapersActivity.java:58)
03-22 17:01:35.828: E/WindowManager(531): at android.app.Activity.performCreate(Activity.java:4465)
03-22 17:01:35.828: E/WindowManager(531): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-22 17:01:35.828: E/WindowManager(531): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
03-22 17:01:35.828: E/WindowManager(531): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
03-22 17:01:35.828: E/WindowManager(531): at android.app.ActivityThread.access$600(ActivityThread.java:123)
03-22 17:01:35.828: E/WindowManager(531): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
03-22 17:01:35.828: E/WindowManager(531): at android.os.Handler.dispatchMessage(Handler.java:99)
03-22 17:01:35.828: E/WindowManager(531): at android.os.Looper.loop(Looper.java:137)
03-22 17:01:35.828: E/WindowManager(531): at android.app.ActivityThread.main(ActivityThread.java:4424)
03-22 17:01:35.828: E/WindowManager(531): at java.lang.reflect.Method.invokeNative(Native Method)
03-22 17:01:35.828: E/WindowManager(531): at java.lang.reflect.Method.invoke(Method.java:511)
03-22 17:01:35.828: E/WindowManager(531): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-22 17:01:35.828: E/WindowManager(531): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-22 17:01:35.828: E/WindowManager(531): at dalvik.system.NativeStart.main(Native Method)
03-22 17:06:32.377: I/Process(531): Sending signal. PID: 531 SIG: 9
请告诉我的代码中10.0.2.2在移动设备上运行此应用时出现问题
答案 0 :(得分：3)
您似乎正在尝试访问本地网络上的localhost网络服务。您应该知道，这样的Web服务只能由计算机上的仿真器访问，该计算机可能与服务器位于同一本地网络上。 真实的设备无法访问本地网络上的Web服务。
要在真实设备上测试您的应用，您需要通过公共网址公开您的网络服务，该网址可以在公共网络上访问。这样做，它会起作用。
答案 1 :(得分：0)
10.0.2.2。对于真实设备更改wlan中服务器的本地IP地址。