Android 应用程序在 Http 请求连接到在线数据库时崩溃

Question

我是 android 的新手，我需要将我的应用程序连接到在线数据库。我创建了数据库和 php 连接文件。我还创建了一个测试 index.php 文件来测试连接：

index.php

<?php
include_once 'connection.php';
echo 'hi';
?>

我也用search.php获取数据：

 <?php


     mysql_connect("localhost","****","*****");
      mysql_select_db("*****");
      $sql=mysql_query("select * from user where username like 'a%'");
      while($row=mysql_fetch_assoc($sql)) $output[]=$row;
      print(json_encode($output));
      mysql_close();

      ?>

这是search.php的输出：

[{"id":"2","username":"adla","password":"123","type":null,"customer_id":null,"employee_id":null}]

我可以从应用程序外部连接到数据库，所以错误可能出在我的代码中。

我尝试了 2 个教程中的两种方法：

http://www.helloandroid.com/tutorials/connecting-mysql-database（使用Post方法）

    public void connectNow(View view)
    {


    String result = null;
    InputStream is = null;
    StringBuilder sb =null;

    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
    //http post
    try{
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://akmiengineering.com/insurance-app/search.php");
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();

        Toast.makeText(getApplicationContext(),"Connection successful!! This is return:" +is , Toast.LENGTH_LONG).show();

    }catch(Exception e){
        Log.e("log_tag", "Error in http connection" + e.toString());


    }

    //convert response to string
    try{
        BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
        sb = new StringBuilder();
        sb.append(reader.readLine() + "\n");
        String line="0";

        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }

        is.close();
        result=sb.toString();
        Toast.makeText(getApplicationContext(),"Connection successful!! This is result:" +result , Toast.LENGTH_LONG).show();

    }catch(Exception e){
        Log.e("log_tag", "Error converting result "+e.toString());
    }

    //paring data
    String fd_id;
    String fd_name;
   try{
        jArray = new JSONArray(result);
        JSONObject json_data=null;

        for(int i=0;i<jArray.length();i++) {
            json_data = jArray.getJSONObject(i);
           fd_id = json_data.getString("username");
            fd_name = json_data.getString("password");
            Toast.makeText(getApplicationContext(), "I'm here!! This is name:" + fd_id + " and this is pass: " + fd_name, Toast.LENGTH_LONG).show();
        }

   }catch(JSONException e1){
      Toast.makeText(getBaseContext(), "No Data Found", Toast.LENGTH_LONG).show();
    }



}

我尝试在 bluestacks 上调试应用程序，因为我没有 android，所以我只是依靠断点来检测错误。当代码到达这里时，应用程序似乎崩溃了：

            HttpResponse response = httpclient.execute(httppost);

http://hmkcode.com/android-internet-connection-using-http-get-httpclient/（使用 GET）

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_http_test);
    EditText etResponse;
    TextView tvIsConnected;

        // get reference to the views
        etResponse = (EditText) findViewById(R.id.etResponse);
        tvIsConnected = (TextView) findViewById(R.id.tvIsConnected);

        // check if you are connected or not
        if(isConnected()){
            tvIsConnected.setBackgroundColor(0xFF00CC00);
            tvIsConnected.setText("You are conncted");
        }
        else{
            tvIsConnected.setText("You are NOT conncted");
        }

        // show response on the EditText etResponse
        etResponse.setText(GET("http://akmiengineering.com/insurance-app/index.php"));

    }

public static String GET(String url){
    InputStream inputStream = null;
    String result = "";
    try {

        // create HttpClient
        HttpClient httpclient = new DefaultHttpClient();

        // make GET request to the given URL
        HttpResponse httpResponse = httpclient.execute(new HttpGet(url));

        // receive response as inputStream
        inputStream = httpResponse.getEntity().getContent();

        // convert inputstream to string
        if(inputStream != null)
            result = convertInputStreamToString(inputStream);
        else
            result = "Did not work!";

    } catch (Exception e) {
        Log.d("InputStream", e.getLocalizedMessage());
    }

    return result;
}

// convert inputstream to String
private static String convertInputStreamToString(InputStream inputStream) throws IOException {
    BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
    String line = "";
    String result = "";
    while((line = bufferedReader.readLine()) != null)
        result += line;

    inputStream.close();
    return result;

}

// check network connection
public boolean isConnected(){
    ConnectivityManager connMgr = (ConnectivityManager) getSystemService(this.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected())
        return true;
    else
        return false;
}

此外，此代码会导致应用程序此时崩溃：

  HttpResponse httpResponse = httpclient.execute(new HttpGet(url));

这两种方法都是同样的问题，但我不知道是什么原因造成的，也不知道如何解决。我试图检测来自 logcat 的错误，但我无法理解它：

07-08 15:08:06.631    2750-2750/com.bluestacks.gamepophome E/bluestacksHome﹕ Hidden apps list thru binder[com.zqgame.fr.en.androidgp, com.igg.bzbee.slotsdeluxe, com.igg.clashoflords2, com.igg.pokerdeluxe, air.com.sublinet.tastytale]
07-08 15:08:06.641    2750-2750/com.bluestacks.gamepophome E/bluestacksHome﹕ Hidden list size 5
07-08 15:08:06.731    2661-2673/com.android.inputmethod.latin W/Binder﹕ Caught a RuntimeException from the binder stub implementation.
    java.lang.NullPointerException
            at android.inputmethodservice.IInputMethodWrapper.setSessionEnabled(IInputMethodWrapper.java:280)
            at com.android.internal.view.IInputMethod$Stub.onTransact(IInputMethod.java:129)
            at android.os.Binder.execTransact(Binder.java:404)
            at dalvik.system.NativeStart.run(Native Method)
07-08 15:08:06.731   2533-29585/system_process W/InputMethodManagerService﹕ Got RemoteException sending setActive(false) notification to pid 7192 uid 10066

我什至通过尝试连接到我的本地主机来测试它，但我遇到了同样的错误。

Answer 1

您是否在清单文件中声明了 Internet 许可。

Answer 2

我认为您可能面临 android 线程问题。通常像 GET 方法这样的方法应该在另一个扩展 AsyncTask 的 class 中，这将运行你的代码在主线程以外的不同线程中。

如果您不想使用 AsyncTask 并想强制您的代码运行都在同一个线程中，您应该在 onCreate 方法中有这样的东西：

if (android.os.Build.VERSION.SDK_INT > 9) {
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);
}

Android 应用程序在 Http 请求连接到在线数据库时崩溃

Android application crashes on Http Request to connect to online database

php

post

android

get

httprequest