尝试使用 Android AsyncTask 从服务器获取响应

Question

我正在尝试学习如何使用 AsyncTask 类来验证其帐户存储在远程服务器和数据库上的用户。

我正在使用一个示例，到目前为止我有这段代码：

package com.problemio;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
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.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.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class LoginActivity extends Activity 
{
    private TextView textView;

    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);

        // Show form for login_email
        final EditText loginEmail = (EditText) findViewById(R.id.login_email);  
        String name = loginEmail.getText().toString();  

        // Show field for password  
        final EditText password = (EditText) findViewById(R.id.password);  
        String text = password.getText().toString();                  

        // Show button for submit
        Button submit = (Button)findViewById(R.id.submit);   




        // Show options for create-profile and forgot-password




        submit.setOnClickListener(new Button.OnClickListener() 
        {  
           public void onClick(View v) 
           {
              String email = loginEmail.getText().toString();
              String pass = password.getText().toString(); 
              sendFeedback(pass, email);
            }
        });        
    }


    public void sendFeedback(String pass , String email) 
    {  
        Log.d( "1" , pass );
        Log.d( "1" , email );

        // Go to db and check if these r legit
        // How do I do that? :)
        ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();  
        postParameters.add(new BasicNameValuePair("username", email ));  
        postParameters.add(new BasicNameValuePair("password", pass ));


    }          



    private class DownloadWebPageTask extends AsyncTask<String, Void, String> 
    {
        @Override
        protected String doInBackground(String... urls) 
        {
            Log.d( "Inner class: " , "Doing stuff in background" );

            String response = "";
            for (String url : urls) {
                DefaultHttpClient client = new DefaultHttpClient();
                HttpGet httpGet = new HttpGet(url);
                try {
                    HttpResponse execute = client.execute(httpGet);
                    InputStream content = execute.getEntity().getContent();

                    BufferedReader buffer = new BufferedReader(
                            new InputStreamReader(content));
                    String s = "";
                    while ((s = buffer.readLine()) != null) {
                        response += s;
                    }

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return response;
        }


        @Override
        protected void onPostExecute(String result) 
        {
            textView.setText(result);
        }    
    }

        public void readWebpage(View view) 
        {
            DownloadWebPageTask task = new DownloadWebPageTask();
            task.execute(new String[] { "http://www.myurl.com" });
        }        
}

并且我在 LogCat 中遇到了一些错误，例如：

02-23 10:51:45.587: D/AndroidRuntime(1670): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<<
02-23 10:51:45.587: D/AndroidRuntime(1670): CheckJNI is ON
02-23 10:51:47.037: D/AndroidRuntime(1670): Calling main entry com.android.commands.pm.Pm
02-23 10:51:47.118: W/ActivityManager(1180): No content provider found for permission revoke: file:///data/local/tmp/Problemio.apk
02-23 10:51:47.267: W/ActivityManager(1180): No content provider found for permission revoke: file:///data/local/tmp/Problemio.apk
02-23 10:51:47.467: I/PackageManager(1180): Removing non-system package:com.problemio
02-23 10:51:47.467: I/ActivityManager(1180): Force stopping package com.problemio uid=10041
02-23 10:51:47.467: I/ActivityManager(1180): Killing proc 1648:com.problemio/10041: force stop
02-23 10:51:47.477: W/ActivityManager(1180): Force removing ActivityRecord{4147f5d0 com.problemio/.LoginActivity}: app died, no saved state
02-23 10:51:47.518: I/ActivityManager(1180):   Force finishing activity ActivityRecord{413e9e98 com.problemio/.ProblemioActivity}
02-23 10:51:47.587: W/InputDispatcher(1180): channel '4160fcd8 com.problemio/com.problemio.ProblemioActivity (server)' ~ Consumer closed input channel or an error occurred.  events=0x8
02-23 10:51:47.587: E/InputDispatcher(1180): channel '4160fcd8 com.problemio/com.problemio.ProblemioActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
02-23 10:51:47.607: I/WindowManager(1180): WIN DEATH: Window{416096c0 com.problemio/com.problemio.LoginActivity paused=false}
02-23 10:51:47.637: I/WindowManager(1180): WIN DEATH: Window{4160fcd8 com.problemio/com.problemio.ProblemioActivity paused=true}
02-23 10:51:47.637: W/InputDispatcher(1180): Attempted to unregister already unregistered input channel '4160fcd8 com.problemio/com.problemio.ProblemioActivity (server)'
02-23 10:51:47.667: I/WindowManager(1180): WINDOW DIED Window{4160fcd8 com.problemio/com.problemio.ProblemioActivity paused=true}
02-23 10:51:47.707: E/InputDispatcher(1180): Received spurious receive callback for unknown input channel.  fd=206, events=0x8
02-23 10:51:48.157: D/dalvikvm(1180): GC_CONCURRENT freed 527K, 9% free 12067K/13255K, paused 10ms+43ms
02-23 10:51:48.587: W/NetworkManagementSocketTagger(1180): setKernelCountSet(10041, 0) failed with errno -2
02-23 10:51:48.587: W/NetworkManagementSocketTagger(1180): setKernelCountSet(10009, 1) failed with errno -2
02-23 10:51:48.598: I/PackageManager(1180): Package com.problemio codePath changed from /data/app/com.problemio-1.apk to /data/app/com.problemio-2.apk; Retaining data and using new
02-23 10:51:48.667: I/PackageManager(1180): Running dexopt on: com.problemio
02-23 10:51:49.247: D/dalvikvm(1681): DexOpt: load 54ms, verify+opt 86ms
02-23 10:51:49.307: W/PackageManager(1180): Code path for pkg : com.problemio changing from /data/app/com.problemio-1.apk to /data/app/com.problemio-2.apk
02-23 10:51:49.317: W/PackageManager(1180): Resource path for pkg : com.problemio changing from /data/app/com.problemio-1.apk to /data/app/com.problemio-2.apk
02-23 10:51:49.327: I/ActivityManager(1180): Force stopping package com.problemio uid=10041
02-23 10:51:49.517: D/PackageManager(1180): New package installed in /data/app/com.problemio-2.apk
02-23 10:51:49.808: I/ActivityManager(1180): Force stopping package com.problemio uid=10041
02-23 10:51:49.997: D/dalvikvm(1275): GC_EXPLICIT freed 235K, 6% free 11344K/12039K, paused 5ms+13ms
02-23 10:51:50.177: D/dalvikvm(1341): GC_EXPLICIT freed 168K, 4% free 9389K/9735K, paused 105ms+9ms
02-23 10:51:50.646: D/dalvikvm(1180): GC_EXPLICIT freed 448K, 10% free 12001K/13255K, paused 83ms+18ms
02-23 10:51:50.728: D/PackageManager(1180): generateServicesMap(android.accounts.AccountAuthenticator): 2 services unchanged
02-23 10:51:50.897: D/PackageManager(1180): generateServicesMap(android.content.SyncAdapter): 4 services unchanged
02-23 10:51:50.929: D/BackupManagerService(1180): Received broadcast Intent { act=android.intent.action.PACKAGE_REMOVED dat=package:com.problemio flg=0x10000010 (has extras) }
02-23 10:51:51.047: I/AccountTypeManager(1408): Loaded meta-data for 1 account types, 0 accounts in 647ms(wall) 12ms(cpu)
02-23 10:51:51.117: D/PackageManager(1180): generateServicesMap(android.accounts.AccountAuthenticator): 2 services unchanged
02-23 10:51:51.217: D/PackageManager(1180): generateServicesMap(android.content.SyncAdapter): 4 services unchanged
02-23 10:51:51.357: D/BackupManagerService(1180): Received broadcast Intent { act=android.intent.action.PACKAGE_ADDED dat=package:com.problemio flg=0x10000010 (has extras) }
02-23 10:51:51.357: V/BackupManagerService(1180): updatePackageParticipantsLocked: com.problemio
02-23 10:51:51.697: W/RecognitionManagerService(1180): no available voice recognition services found
02-23 10:51:52.817: I/AccountTypeManager(1408): Loaded meta-data for 1 account types, 0 accounts in 45ms(wall) 15ms(cpu)
02-23 10:51:52.919: D/BackupManagerService(1180): Received broadcast Intent { act=android.intent.action.PACKAGE_REPLACED dat=package:com.problemio flg=0x10000010 (has extras) }
02-23 10:51:52.940: V/BackupManagerService(1180): updatePackageParticipantsLocked: com.problemio
02-23 10:51:53.977: D/dalvikvm(1180): GC_EXPLICIT freed 604K, 10% free 12042K/13255K, paused 8ms+129ms
02-23 10:51:54.157: D/AndroidRuntime(1670): Shutting down VM
02-23 10:51:54.177: D/dalvikvm(1670): GC_CONCURRENT freed 101K, 78% free 456K/2048K, paused 1ms+1ms
02-23 10:51:54.187: D/jdwp(1670): Got wake-up signal, bailing out of select
02-23 10:51:54.187: D/dalvikvm(1670): Debugger has detached; object registry had 1 entries
02-23 10:51:54.197: I/AndroidRuntime(1670): NOTE: attach of thread 'Binder Thread #3' failed
02-23 10:51:55.077: D/AndroidRuntime(1689): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<<
02-23 10:51:55.077: D/AndroidRuntime(1689): CheckJNI is ON
02-23 10:51:56.267: D/AndroidRuntime(1689): Calling main entry com.android.commands.am.Am
02-23 10:51:56.317: I/ActivityManager(1180): START {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.problemio/.ProblemioActivity} from pid 1689
02-23 10:51:56.347: W/WindowManager(1180): Failure taking screenshot for (180x300) to layer 21000
02-23 10:51:56.417: D/AndroidRuntime(1689): Shutting down VM
02-23 10:51:56.447: D/dalvikvm(1699): Not late-enabling CheckJNI (already on)
02-23 10:51:56.447: I/AndroidRuntime(1689): NOTE: attach of thread 'Binder Thread #3' failed
02-23 10:51:56.457: D/dalvikvm(1689): GC_CONCURRENT freed 101K, 77% free 485K/2048K, paused 1ms+3ms
02-23 10:51:56.457: D/jdwp(1689): Got wake-up signal, bailing out of select
02-23 10:51:56.467: D/dalvikvm(1689): Debugger has detached; object registry had 1 entries
02-23 10:51:56.517: I/ActivityManager(1180): Start proc com.problemio for activity com.problemio/.ProblemioActivity: pid=1699 uid=10041 gids={3003}
02-23 10:51:56.977: W/NetworkManagementSocketTagger(1180): setKernelCountSet(10041, 1) failed with errno -2
02-23 10:51:57.087: I/ActivityManager(1180): START {cmp=com.problemio/.LoginActivity} from pid 1699
02-23 10:51:57.606: D/gralloc_goldfish(1699): Emulator without GPU emulation detected.
02-23 10:51:58.047: E/ActivityThread(1435): Failed to find provider info for com.android.inputmethod.latin.dictionarypack
02-23 10:51:58.117: E/BinaryDictionaryGetter(1435): Could not find a dictionary pack
02-23 10:51:58.207: I/ActivityManager(1180): Displayed com.problemio/.LoginActivity: +916ms (total +1s823ms)
02-23 10:51:58.237: I/ActivityManager(1180): Displayed com.problemio/.ProblemioActivity: +1s854ms
02-23 10:51:58.427: W/NetworkManagementSocketTagger(1180): setKernelCountSet(10009, 0) failed with errno -2
02-23 10:51:58.868: E/ActivityThread(1435): Failed to find provider info for com.android.inputmethod.latin.dictionarypack
02-23 10:51:58.886: E/BinaryDictionaryGetter(1435): Could not find a dictionary pack
02-23 10:53:59.657: W/SoundPool(1180):   sample 0 not READY
02-23 10:53:59.748: D/PhoneStatusBar(1233): disable: < expand icons alerts ticker system_info BACK HOME recent* CLOCK >
02-23 10:54:00.097: I/ARMAssembler(35): generated scanline__00000077:03515104_00009002_00000000 [127 ipp] (149 ins) at [0x419dea80:0x419decd4] in 2956444 ns
02-23 10:54:00.117: D/PhoneStatusBar(1233): disable: < expand icons alerts ticker system_info back* home* recent clock* >
02-23 10:54:03.086: D/1(1699): Please enter your password
02-23 10:54:03.086: D/1(1699): Plase enter your login email address
02-23 10:54:41.017: A/BatteryStatsImpl(1180): problem reading network stats
02-23 10:54:41.017: A/BatteryStatsImpl(1180): java.lang.IllegalStateException: problem parsing idx 1
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:300)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:250)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl.getNetworkStatsDetailGroupedByUid(BatteryStatsImpl.java:5734)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl.access$100(BatteryStatsImpl.java:76)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl$Uid.computeCurrentTcpBytesReceived(BatteryStatsImpl.java:2457)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl$Uid.getTcpBytesReceived(BatteryStatsImpl.java:2446)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl.writeSummaryToParcel(BatteryStatsImpl.java:5437)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl.writeLocked(BatteryStatsImpl.java:4836)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.os.BatteryStatsImpl.writeAsyncLocked(BatteryStatsImpl.java:4818)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.server.am.ActivityManagerService.updateCpuStatsNow(ActivityManagerService.java:1649)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.server.am.ActivityManagerService$3.run(ActivityManagerService.java:1531)
02-23 10:54:41.017: A/BatteryStatsImpl(1180): Caused by: java.io.FileNotFoundException: /proc/net/xt_qtaguid/stats: open failed: ENOENT (No such file or directory)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at libcore.io.IoBridge.open(IoBridge.java:406)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at java.io.FileInputStream.<init>(FileInputStream.java:78)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:269)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   ... 10 more
02-23 10:54:41.017: A/BatteryStatsImpl(1180): Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at libcore.io.Posix.open(Native Method)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   at libcore.io.IoBridge.open(IoBridge.java:390)
02-23 10:54:41.017: A/BatteryStatsImpl(1180):   ... 12 more
02-23 10:55:09.777: D/dalvikvm(1261): GC_CONCURRENT freed 384K, 6% free 9529K/10119K, paused 8ms+9ms
02-23 10:56:33.198: W/ThrottleService(1180): unable to find stats for iface rmnet0
02-23 11:00:46.967: A/NetworkStats(1180): problem reading network stats
02-23 11:00:46.967: A/NetworkStats(1180): java.lang.IllegalStateException: problem parsing idx 1
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:300)
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.server.NetworkManagementService.getNetworkStatsUidDetail(NetworkManagementService.java:1282)
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.server.net.NetworkStatsService.performPollLocked(NetworkStatsService.java:831)
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.server.net.NetworkStatsService.performPoll(NetworkStatsService.java:799)
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.server.net.NetworkStatsService.access$100(NetworkStatsService.java:128)
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.server.net.NetworkStatsService$3.onReceive(NetworkStatsService.java:633)
02-23 11:00:46.967: A/NetworkStats(1180):   at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:728)
02-23 11:00:46.967: A/NetworkStats(1180):   at android.os.Handler.handleCallback(Handler.java:605)
02-23 11:00:46.967: A/NetworkStats(1180):   at android.os.Handler.dispatchMessage(Handler.java:92)
02-23 11:00:46.967: A/NetworkStats(1180):   at android.os.Looper.loop(Looper.java:137)
02-23 11:00:46.967: A/NetworkStats(1180):   at android.os.HandlerThread.run(HandlerThread.java:60)
02-23 11:00:46.967: A/NetworkStats(1180): Caused by: java.io.FileNotFoundException: /proc/net/xt_qtaguid/stats: open failed: ENOENT (No such file or directory)
02-23 11:00:46.967: A/NetworkStats(1180):   at libcore.io.IoBridge.open(IoBridge.java:406)
02-23 11:00:46.967: A/NetworkStats(1180):   at java.io.FileInputStream.<init>(FileInputStream.java:78)
02-23 11:00:46.967: A/NetworkStats(1180):   at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:269)
02-23 11:00:46.967: A/NetworkStats(1180):   ... 10 more
02-23 11:00:46.967: A/NetworkStats(1180): Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
02-23 11:00:46.967: A/NetworkStats(1180):   at libcore.io.Posix.open(Native Method)
02-23 11:00:46.967: A/NetworkStats(1180):   at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
02-23 11:00:46.967: A/NetworkStats(1180):   at libcore.io.IoBridge.open(IoBridge.java:390)
02-23 11:00:46.967: A/NetworkStats(1180):   ... 12 more
02-23 11:01:00.456: D/dalvikvm(1180): GC_CONCURRENT freed 632K, 10% free 12039K/13255K, paused 10ms+15ms
02-23 11:02:33.617: D/dalvikvm(1261): GC_CONCURRENT freed 384K, 6% free 9529K/10119K, paused 24ms+7ms
02-23 11:06:33.266: W/ThrottleService(1180): unable to find stats for iface rmnet0

我不太确定这意味着什么:)

但是我在我的服务器日志中看到该 url 没有被使用hit，这是重要的部分，这意味着这段代码最终没有向我的身份验证服务器发出请求。知道这里出了什么问题吗？

谢谢！

Answer 1

在您的 sendFeedback(...) 方法中执行类似以下操作...

public void sendFeedback(String pass , String email) 
{  
    Log.d( "1" , pass );
    Log.d( "1" , email );

    String[] params = new String[] { "http://www.myurl.com", email, pass };

    DownloadWebPageTask task = new DownloadWebPageTask();
    task.execute(params);
}

然后在 AsncTask 的 doInBackground(...) 方法中您可以像这样检索它们...

private class DownloadWebPageTask extends AsyncTask<String, Void, String> 
{
    @Override
    protected String doInBackground(String... theParams) 
    {
        String myUrl = theParams[0];
        String myEmail = theParams[1];
        String myPassword = theParams[2];

        ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();  
        postParameters.add(new BasicNameValuePair("username", myEmail ));  
        postParameters.add(new BasicNameValuePair("password", myPassword ));

        ...

    }
}

您还需要使用 HttpPost 而不是 HttpGet。