使用Android应用程序无法连接到PHP

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现在我正在发展，需要连接到数据库的应用程序，我试图将Android应用程序直接连接到MySQL，但我失败了，人很多说我应该这样做来用PHP。所以在平均时间我想这code连接到PHP。

包com.climacon.androidapp;进口java.io.BufferedReader中;进口的java.io.InputStream;进口java.io.InputStreamReader中;进口org.apache.http.HttpEntity;进口org.apache.http.Htt presponse;进口org.apache.http.client.HttpClient;进口org.apache.http.client.methods.HttpPost;进口org.apache.http.impl.client.DefaultHttpClient;进口org.json.JSONException;进口org.json.JSONObject;进口android.util.Log;公共类Phpmysql {  公共静态的JSONObject连接（字符串URL）{    InputStream为= NULL;    字符串结果=;    JSONObject的jArray = NULL;    // URL从下载JSON数据    尝试{        HttpClient的HttpClient的=新DefaultHttpClient（）;        HttpPost httppost =新HttpPost（192.168.1.20/Project/）;        HTT presponse响应= httpclient.execute（httppost）;        HttpEntity实体= response.getEntity（）;        是= entity.getContent（）;    }赶上（例外五）{        Log.e（log_tag，在HTTP连接错误+ e.toString（））;    }    //响应转换成字符串    尝试{        读者的BufferedReader =新的BufferedReader（新的InputStreamReader（                是，ISO-8859-1），8）;        StringBuilder的SB =新的StringBuilder（）;        串线= NULL;        而（（行= reader.readLine（））！= NULL）{            sb.append（行+\\ n）;        }        is.close（）;        结果= sb.toString（）;    }赶上（例外五）{        Log.e（log_tag，错误转换结果+ e.toString（））;    }    尝试{        jArray =新的JSONObject（结果）;    }赶上（JSONException E）{        Log.e（log_tag，错误分析数据+ e.toString（））;    }    返回jArray;  }}

我呼吁从另一个类此功能（连接（）），但它不工作，它给了我以下错误消息

错误http连接android.os.NetworkOnMainThreadException错误转换结果显示java.lang.NullPointerException：锁== NULL解析错误数据org.json.JSONException：在字符输入0结束

和我添加

＆LT;使用许可权的android：NAME =android.permission.INTERNET对/＆GT;＆LT;使用许可权的android：NAME =android.permission.ACCESS_NETWORK_STATE/＆GT;

现在，它正在使用异步任务，但是当我尝试

NNode节点= NULL;node.set_temp（j​​Object.length（））;value4.setText（将String.valueOf（tempprogress））

我收到以下错误

E / JSON解析器（3336）：错误分析数据org.json.JSONException：价值与LT; java.lang.String类型的DOCTYPE不能转换到的JSONObjectE / ActivityManager（714）：应用程序崩溃！工艺：com.climacon.androidappE / AndroidRuntime（3336）：致命异常：主要E / AndroidRuntime（3336）：工艺：com.climacon.androidapp，PID：3336E / AndroidRuntime（3336）：显示java.lang.NullPointerExceptionE / AndroidRuntime（3336）：在com.climacon.androidapp.climatemonitor $ ConnectToPHP.onPostExecute（climatemonitor.java:83）E / AndroidRuntime（3336）：在com.climacon.androidapp.climatemonitor $ ConnectToPHP.onPostExecute（climatemonitor.java:1）E / AndroidRuntime（3336）：在android.os.AsyncTask.finish（AsyncTask.java:632）E / AndroidRuntime（3336）：在android.os.AsyncTask.access $ 600（AsyncTask.java:177）E / AndroidRuntime（3336）：在android.os.AsyncTask $ InternalHandler.handleMessage（AsyncTask.java:645）E / AndroidRuntime（3336）：在android.os.Handler.dispatchMessage（Handler.java:102）E / AndroidRuntime（3336）：在android.os.Looper.loop（Looper.java:157）E / AndroidRuntime（3336）：在android.app.ActivityThread.main（ActivityThread.java:5872）E / AndroidRuntime（3336）：在java.lang.reflect.Method.invokeNative（本机方法）E / AndroidRuntime（3336）：在java.lang.reflect.Method.invoke（Method.java:515）E / AndroidRuntime（3336）：在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1069）E / AndroidRuntime（3336）：在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:885）E / AndroidRuntime（3336）：在dalvik.system.NativeStart.main（本机方法）

解决方案

在http连接android.os.NetworkOnMainThreadException错误

以上说的你在做网络调用主线程异常状态，你必须这样做，在的AsyncTask 或处理程序。看看下面的类：

类ConnectToPHP扩展的AsyncTask＆LT;字符串，字符串，字符串＆GT;{    @覆盖    在preExecute保护无效（）    {        // TODO自动生成方法存根        //显示进度对话框这里        super.on preExecute（）;    }    @覆盖    保护字符串doInBackground（字符串... PARAMS）    {       // TODO自动生成方法存根       的JSONObject jObject = Phpmysql.connections（PARAMS [0]）;       的System.out.println（jObject.toString（））;       //做你的code在这里       返回null;    }    @覆盖    保护无效onPostExecute（字符串结果）    {        // TODO自动生成方法存根        //解雇进度对话框这里        super.onPostExecute（结果）;    }}

调用此的AsyncTask 类的onCreate（）象下面这样的活动：

字符串my_url =192.168.1.20/Project/index.php;新ConnectToPHP.execute（my_url）;

Now I was developing an application which requires connection to a database, I tried to connect the android application directly to MYSQL but I failed and alot of people said that I should do it through PHP. So in the mean time I am trying this code to connect to a PHP.

package com.climacon.androidapp; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONException; import org.json.JSONObject; import android.util.Log; public class Phpmysql { public static JSONObject connections (String url) { InputStream is = null; String result = ""; JSONObject jArray = null; // Download JSON data from URL try { HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost("192.168.1.20/Project/"); HttpResponse response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); is = entity.getContent(); } 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); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); result = sb.toString(); } catch (Exception e) { Log.e("log_tag", "Error converting result " + e.toString()); } try { jArray = new JSONObject(result); } catch (JSONException e) { Log.e("log_tag", "Error parsing data " + e.toString()); } return jArray; } }

And I call this function (connections()) from another class but it doesn't work and it gives me the following error message

Error in http connection android.os.NetworkOnMainThreadException Error converting result java.lang.NullPointerException: lock == null Error parsing data org.json.JSONException: End of input at character 0 of

and I added

<uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Now it is working using the ASYNC task but when i try

NNode node = null; node.set_temp(jObject.length()); value4.setText(String.valueOf(tempprogress))

i get the following error

E/JSON Parser(3336): Error parsing data org.json.JSONException: Value <!DOCTYPE of type java.lang.String cannot be converted to JSONObject E/ActivityManager(714): App crashed! Process: com.climacon.androidapp E/AndroidRuntime(3336): FATAL EXCEPTION: main E/AndroidRuntime(3336): Process: com.climacon.androidapp, PID: 3336 E/AndroidRuntime(3336): java.lang.NullPointerException E/AndroidRuntime(3336): at com.climacon.androidapp.climatemonitor$ConnectToPHP.onPostExecute(climatemonitor.java:83) E/AndroidRuntime(3336): at com.climacon.androidapp.climatemonitor$ConnectToPHP.onPostExecute(climatemonitor.java:1) E/AndroidRuntime(3336): at android.os.AsyncTask.finish(AsyncTask.java:632) E/AndroidRuntime(3336): at android.os.AsyncTask.access$600(AsyncTask.java:177) E/AndroidRuntime(3336): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645) E/AndroidRuntime(3336): at android.os.Handler.dispatchMessage(Handler.java:102) E/AndroidRuntime(3336): at android.os.Looper.loop(Looper.java:157) E/AndroidRuntime(3336): at android.app.ActivityThread.main(ActivityThread.java:5872) E/AndroidRuntime(3336): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime(3336): at java.lang.reflect.Method.invoke(Method.java:515) E/AndroidRuntime(3336): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1069) E/AndroidRuntime(3336): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:885) E/AndroidRuntime(3336): at dalvik.system.NativeStart.main(Native Method)

解决方案

Error in http connection android.os.NetworkOnMainThreadException

Above exception state that you are doing network calling on main thread, you have to do it in asynctask or handler. Have a look at below class:

class ConnectToPHP extends AsyncTask<String, String, String> { @Override protected void onPreExecute() { // TODO Auto-generated method stub // show progress dialog here super.onPreExecute(); } @Override protected String doInBackground(String... params) { // TODO Auto-generated method stub JSONObject jObject = Phpmysql.connections(params[0]); System.out.println(jObject.toString()); // do your code here return null; } @Override protected void onPostExecute(String result) { // TODO Auto-generated method stub // dismiss progress dialog here super.onPostExecute(result); } }

Call this asynctask class in onCreate() of activity like below:

String my_url = "192.168.1.20/Project/index.php"; new ConnectToPHP.execute(my_url);