我一直在开发一个应用程序，公平的预测是它的一部分..它也包含一个webpart ..但我无法登录到那个部分..应用程序终止到那个时间..登录页面链接到一个jsp页面并转入一个mysql数据库..我在这里发布代码..请帮助我..提前感谢..
package com.example.tracemeendpointsjson;
import java.util.ArrayList;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class TLogin extends Activity {
EditText uname,pwd;
Button log,signup;
String response="";
NameValuePair v;
String LoginID,LoginPassword;
HttpRequestClass mynetworkclass;
ArrayList<NameValuePair> namevaluepair;
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.tlogin);
uname=(EditText) findViewById(R.id.uname);
pwd=(EditText) findViewById(R.id.pwd);
log=(Button) findViewById(R.id.login);
signup=(Button) findViewById(R.id.bSignup);
log.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
LoginID=uname.getText().toString();
LoginPassword=pwd.getText().toString();
//CommonClassForLogin q=(CommonClassForLogin) getApplication();
//q.myUID=LoginID;
String url="http://"+details.ip+"taxinew/mobile/login.jsp";
new AsyncTaskLogin().execute(url,LoginID,LoginPassword);
}
});
}
public class AsyncTaskLogin extends AsyncTask<String, Integer, String>
{
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
mynetworkclass=new HttpRequestClass();
namevaluepair=new ArrayList<NameValuePair>();
namevaluepair.add(new BasicNameValuePair("username",params[1]));
namevaluepair.add(new BasicNameValuePair("password",params[2]));
try {
String result=mynetworkclass.getinformation(params[0],namevaluepair);
Log.d("dsfwewerte", result);
result=result.replaceAll("\\r|\\n", "");
return result;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
//Log.d("222222222", result);
if(result.equals("0"))
{
Toast.makeText(getApplicationContext(),"Welcomes You", Toast.LENGTH_SHORT).show();
Intent in=new Intent(getApplicationContext(), Trip.class);
startActivity(in);
//Log.d("11111111111", result);
}
else
{
Toast.makeText(getApplicationContext(),"Wrong Entry", Toast.LENGTH_SHORT).show();
Intent in1=new Intent(getApplicationContext(), Home.class);
startActivity(in1);
//Log.d("0000000000", result);
}
}
}
}
package com.example.tracemeendpointsjson;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
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.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
import android.widget.Toast;
public class HttpRequestClass {
HttpClient httpclient;
public String getinformation(String url,ArrayList<NameValuePair> namevaluepair) throws ParseException, IOException
{
httpclient=new DefaultHttpClient();
HttpPost request=new HttpPost(url);
request.setEntity(new UrlEncodedFormEntity(namevaluepair));
try
{
HttpResponse respnse=httpclient.execute(request);
int status=respnse.getStatusLine().getStatusCode();
if(status==200)
{
HttpEntity e=respnse.getEntity();
String data=EntityUtils.toString(e);
return data;
}
}
catch(ClientProtocolException e)
{
e.printStackTrace();
}
catch(IOException e)
{
e.printStackTrace();
}
return null;
}
public String getsingleinformation(String url) throws ParseException, IOException
{
httpclient=new DefaultHttpClient();
HttpPost request=new HttpPost(url);
try
{
HttpResponse respnse=httpclient.execute(request);
int status=respnse.getStatusLine().getStatusCode();
if(status==200)
{
HttpEntity e=respnse.getEntity();
String data=EntityUtils.toString(e);
return data;
}
}
catch(ClientProtocolException e)
{
e.printStackTrace();
}
catch(IOException e)
{
e.printStackTrace();
}
return null;
}
}
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.tracemeendpointsjson"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.SEND_SMS"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<application
android:icon="@drawable/traffic"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<uses-library android:name="com.google.android.maps"/>
<activity
android:name="com.example.tracemeendpointsjson.Home"
android:label="@string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MainActivity"></activity>
<activity
android:name=".UploadDetails"></activity>
<activity
android:name=".CurrentLocation"></activity>
<activity
android:name=".GmailLogin"></activity>
<activity
android:name=".MailReceivers"></activity>
<activity
android:name=".ShowWeather"></activity>
<activity
android:name=".DisplayWeather"></activity>
<activity
android:name=".Trip"></activity>
<activity
android:name=".ShowRoute"></activity>
<activity
android:name=".Parking"></activity>
<activity
android:name=".Estfare"></activity>
<activity
android:name=".GetFare"></activity>
<activity
android:name=".TLogin">
</activity>
<activity
android:name=".ParkingPlaceShow"></activity>
<service android:name=".ServiceClass" >
</service>
<!-- <service android:name=".GPSTracker"></service> -->
</application>
</manifest>
03-20 09:51:30.866: E/AndroidRuntime(476): FATAL EXCEPTION: main
03-20 09:51:30.866: E/AndroidRuntime(476): java.lang.NullPointerException
03-20 09:51:30.866: E/AndroidRuntime(476): at com.example.tracemeendpointsjson.TLogin$AsyncTaskLogin.onPostExecute(TLogin.java:85)
03-20 09:51:30.866: E/AndroidRuntime(476): at com.example.tracemeendpointsjson.TLogin$AsyncTaskLogin.onPostExecute(TLogin.java:1)
03-20 09:51:30.866: E/AndroidRuntime(476): at android.os.AsyncTask.finish(AsyncTask.java:417)
03-20 09:51:30.866: E/AndroidRuntime(476): at android.os.AsyncTask.access$300(AsyncTask.java:127)
03-20 09:51:30.866: E/AndroidRuntime(476): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
03-20 09:51:30.866: E/AndroidRuntime(476): at android.os.Handler.dispatchMessage(Handler.java:99)
03-20 09:51:30.866: E/AndroidRuntime(476): at android.os.Looper.loop(Looper.java:130)
03-20 09:51:30.866: E/AndroidRuntime(476): at android.app.ActivityThread.main(ActivityThread.java:3683)
03-20 09:51:30.866: E/AndroidRuntime(476): at java.lang.reflect.Method.invokeNative(Native Method)
03-20 09:51:30.866: E/AndroidRuntime(476): at java.lang.reflect.Method.invoke(Method.java:507)
03-20 09:51:30.866: E/AndroidRuntime(476): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-20 09:51:30.866: E/AndroidRuntime(476): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-20 09:51:30.866: E/AndroidRuntime(476): at dalvik.system.NativeStart.main(Native Method)
03-20 09:51:30.896: W/ActivityManager(83): Force finishing activity com.example.tracemeendpointsjson/.TLogin
03-20 09:51:31.428: W/ActivityManager(83): Activity pause timeout for HistoryRecord{40803618 com.example.tracemeendpointsjson/.TLogin}
03-20 09:51:33.555: E/InputDispatcher(83): channel '40800e70 com.example.tracemeendpointsjson/com.example.tracemeendpointsjson.Home (server)' ~ Consumer closed input channel or an error occurred. events=0x8
03-20
09:51:33.555: E/InputDispatcher(83): channel '40800e70 com.example.tracemeendpointsjson/com.example.tracemeendpointsjson.Home (server)' ~ Channel is unrecoverably broken and will be disposed!
Login.jsp如下：
<%--
Document : login
--%>
<%@page import="javax.swing.JOptionPane,DB.DbCon"%>
<%@page import="org.json.JSONObject" %>
<%@page import="org.json.JSONArray" %>
<%@page import="java.sql.ResultSet"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%
String username=request.getParameter("username");
String password=request.getParameter("password");
JSONObject jo= new JSONObject();
//JSONArray ja=new JSONArray();
String query="select * from Userdetails where name='"+username+"' and pwd='"+password+"' ";
DbCon o=new DbCon();
ResultSet rs=o.selects(query);
if(rs.next()){
jo.accumulate("0", true);
}
else
{
jo.accumulate("1", false);
}
out.print(jo);
%>
答案 0 :(得分：2)
试试这些代码..我认为这是问题所在。
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
String result;
mynetworkclass=new HttpRequestClass();
namevaluepair=new ArrayList<NameValuePair>();
namevaluepair.add(new BasicNameValuePair("username",params[1]));
namevaluepair.add(new BasicNameValuePair("password",params[2]));
try {
result=mynetworkclass.getinformation(params[0],namevaluepair);
Log.d("dsfwewerte", result);
result=result.replaceAll("\\r|\\n", "");
return result;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
答案 1 :(得分：1)
您的result为空，对if条件的简单更改可以解决此问题
if("0".equals(result))
答案 2 :(得分：0)
除了null之外，尝试在result方法中返回doInBackground。在该方法结束时，您返回null，这就是它抛出nullpointer excepection的原因。
或者您需要在onPostExecute方法中检查结果的空值，以防止抛出异常。
@Override protected String doInBackground(String... params) { // TODO Auto-generated method stub mynetworkclass=new HttpRequestClass(); namevaluepair=new ArrayList<NameValuePair>(); namevaluepair.add(new BasicNameValuePair("username",params[1])); namevaluepair.add(new BasicNameValuePair("password",params[2])); try { String result=mynetworkclass.getinformation(params[0],namevaluepair); Log.d("dsfwewerte", result); result=result.replaceAll("\\r|\\n", ""); return result; } catch (Exception e) { e.printStackTrace(); } return result; <----- Check this line. } @Override protected void onPostExecute(String result) { // TODO Auto-generated method stub super.onPostExecute(result); //Check for the result is null or not. if(result != null) { if(result.equals("0")) {} } }
答案 3 :(得分：0)
您可以使用result返回"with No data" default并与之匹配，您也可以调试并检查您的回复内容