Android Post Request Error using HttpURLConnection

Question

I am trying to do a post request in Android. This is the code I am using but it cause the app to crash

    String urlParameters = "user="+ email.getText().toString() + "&name="+ Username.getText().toString() + "&pass="+ pass.getText().toString() +"";

    // Send post request
    URL serverUrl =
            new URL("http://schoolcheating.3eeweb.com/new_user.php");
    HttpURLConnection urlConnection = (HttpURLConnection) serverUrl.openConnection();

    // Indicate that we want to write to the HTTP request body
    urlConnection.setDoOutput(true);
    urlConnection.setRequestMethod("POST");

    // Writing the post data to the HTTP request body
    BufferedWriter httpRequestBodyWriter =
            new BufferedWriter(new OutputStreamWriter(urlConnection.getOutputStream()));
    httpRequestBodyWriter.write(urlParameters);
    httpRequestBodyWriter.close();

The crash happens at the defining off "httpRequestBodyWriter". Here is the error log:

10-24 19:48:04.049  10501-10501/com.example.mohamedsherif.mysql E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.mohamedsherif.mysql, PID: 10501
    java.lang.IllegalStateException: Could not execute method of the activity
            at android.view.View$1.onClick(View.java:4221)
            at android.view.View.performClick(View.java:5155)
            at android.view.View$PerformClick.run(View.java:20747)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:5832)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
     Caused by: java.lang.reflect.InvocationTargetException
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4216)
            at android.view.View.performClick(View.java:5155)
            at android.view.View$PerformClick.run(View.java:20747)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:5832)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
     Caused by: android.os.NetworkOnMainThreadException
            at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
            at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
            at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
            at java.net.InetAddress.getAllByName(InetAddress.java:215)
            at com.android.okhttp.HostResolver$1.getAllByName(HostResolver.java:29)
            at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:232)
            at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:124)
            at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:361)
            at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:289)
            at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:373)
            at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:106)
            at com.android.okhttp.internal.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:208)
            at com.example.mohamedsherif.mysql.MainActivity.llll(MainActivity.java:73)
            at com.example.mohamedsherif.mysql.MainActivity.cr(MainActivity.java:57)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4216)
            at android.view.View.performClick(View.java:5155)
            at android.view.View$PerformClick.run(View.java:20747)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:5832)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)

also this is the php code of the file that i send to it the post request

<?php

/*
 * Following code will create a new product row
 * All product details are read from HTTP Post Request
*/

// array for JSON response
$response = array();

// check for required fields
if (isset($_POST['name'])) {
$user = $_POST['user']; //User Name
$pass = $_POST['pass']; //Password
$name = $_POST['name']; //Name
$school = $_POST['school']; //School
$type = $_POST['type']; //Type
$pic = $_POST['pic']; //Profile Picture


// include db connect class
require_once __DIR__ . '/db_connect.php';

// connecting to db
$db = new DB_CONNECT();

// mysql inserting a new row
$result = mysql_query("INSERT INTO user(username, name, school, type, profile_picture, password) VALUES('$user', '$name', '$school', '$type', '$pic', '$pass')");

// check if row inserted or not
if ($result) {
    // successfully inserted into database
    $response["success"] = 1;
    $response["message"] = "User successfully created.";

    // echoing JSON response
    echo json_encode($response);
} else {
    // failed to insert row
    $response["success"] = 0;
    $response["message"] = "Oops! An error occurred.";

    // echoing JSON response
    echo json_encode($response);
}
} else {
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";

// echoing JSON response
echo json_encode($response);
}
?>

Dude, NullPointer in your urlConnection. Check if urlConnection gets HTTP_OK or not — Ankur Aggarwal, Oct 24 '15 at 17:43
@MohamedSherif: [NetworkOnMainThreadException](http://stackoverflow.com/questions/6343166/android-os-networkonmainthreadexception) — ρяσѕρєя K, Oct 24 '15 at 17:51
You have **extremely serious security issues** with this PHP code (SQL injection and unhashed/unsalted passwords). You will put your users' security, and your system, at risk if you use it. Switch to a database library that is still currently maintained, use parameter binding for your queries, and an appropriate hashing/salting algorithm for your password storage. — halfer, Oct 24 '15 at 19:38
Yes i know @halfer this is only for testing of course before publishing i will close sql injections and xss and csrf but this is only for testing Thanks — Mohamed Sherif, Oct 24 '15 at 19:46

Shishupal Shakya · Accepted Answer · 2015-10-25T05:09:24.057

According to your Error logs you are getting NetworkOnMainThreadException ,this is because you are performing network operations on main thread i.e UI thread .You need to perform this operation inside a background thread like AsyncTask .Put your network connection code inside doInBackground() of AsyncTask .

private class BackgroundOperation extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String... params) 
        //Your network connection code should be here .
        String response = postCall();
        return response ;
    }

    @Override
    protected void onPostExecute(String result) {
        //Print your response here .
        Log.d("Post Response",result);

    }

    @Override
    protected void onPreExecute() {}

    @Override
    protected void onProgressUpdate(Void... values) {}
}

    public String  postCall(){
    URL url;
    HashMap<String ,String> postDataParams = new HashMap<String ,String>();
        postDataParams .put("user", email.getText().toString());
        postDataParams .put("name", Username.getText().toString());
        postDataParams .put("pass", pass.getText().toString());

    String response = "";
    try {
        url = new URL(""http://schoolcheating.3eeweb.com/new_user.php"");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setReadTimeout(15000);
        conn.setConnectTimeout(15000);
        conn.setRequestMethod("POST");
        conn.setDoInput(true);
        conn.setDoOutput(true);
        OutputStream os = conn.getOutputStream();
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
        writer.write(getPostDataString(postDataParams));
        writer.flush();
        writer.close();
        os.close();
        int responseCode=conn.getResponseCode();
        if(responseCode == HttpsURLConnection.HTTP_OK){
            String line;
            BufferedReader br=new BufferedReader(new InputStreamReader(conn.getInputStream()));
            while ((line=br.readLine()) != null) {response+=line;}}else {
            response="";    }
    } catch (Exception e) {
        e.printStackTrace();}
    return response;
}

 private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException{
        StringBuilder result = new StringBuilder();
        boolean first = true;
        for(Map.Entry<String, String> entry : params.entrySet()){
            if (first)
                first = false;
            else
                result.append("&");

            result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }

        return result.toString();
    }

Now you can call above from from your activity's onCreate() function using below code .

new BackgroundOperation().execute("");

Note : Don't forget to mention below permission in your manifest.xml

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

The problem you have mentioned here ,has been solved ,now should upvote and accept the answer . — Shishupal Shakya, Oct 24 '15 at 19:00
You should ask another question with the problem you are facing now . — Shishupal Shakya, Oct 24 '15 at 19:03
Of course no cause it is the same problem and i am sure that my php code is working cause i tested it so the problem has to be in the http connection done from android and that means you didnt solve my question — Mohamed Sherif, Oct 24 '15 at 19:32
I have edited the above answer to meet your requirement , It's working code for me . I have printed the response in Logcat ,so check your Logcat after executing above code . — Shishupal Shakya, Oct 25 '15 at 04:41
Thanks i am going test when i go back home and tell you but it looks like it works @Android Dev — Mohamed Sherif, Oct 25 '15 at 04:44
I am getting {"success":1,"message":"User successfully created."} in my Logcat . So it should work for you definitely . — Shishupal Shakya, Oct 25 '15 at 05:11
Really Thanks you have solved a problem that i faced for about a year — Mohamed Sherif, Oct 25 '15 at 15:16

Android Post Request Error using HttpURLConnection

1 Answers1