Hello. Trying to make a POST request for ajax page using HttpURLConnection . Do not kick much, I just started practicing Java and Android today. Testing for API 22 (Intel x86). In normal chrome, the same page loads normally. Logcat:

 03-24 10:23:26.842 4679-4679/? I/art: Late-enabling -Xcheck:jni 03-24 10:23:27.402 4679-4679/com.gobonus.gobonus D/AndroidRuntime: Shutting down VM 03-24 10:23:27.427 4679-4679/com.gobonus.gobonus E/AndroidRuntime: FATAL EXCEPTION: main Process: com.gobonus.gobonus, PID: 4679 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gobonus.gobonus/com.gobonus.gobonus.WelcomeActivity}: android.os.NetworkOnMainThreadException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2358) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2420) at android.app.ActivityThread.access$900(ActivityThread.java:154) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5294) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699) Caused by: android.os.NetworkOnMainThreadException at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147) at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:110) at libcore.io.IoBridge.connectErrno(IoBridge.java:137) at libcore.io.IoBridge.connect(IoBridge.java:122) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:183) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:456) at java.net.Socket.connect(Socket.java:882) at com.android.okhttp.internal.Platform.connectSocket(Platform.java:174) at com.android.okhttp.Connection.connect(Connection.java:152) at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:276) at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:211) at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:382) at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:106) at com.android.okhttp.internal.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:217) at com.gobonus.gobonus.Request.<init>(Request.java:65) at com.gobonus.gobonus.WelcomeActivity.onCreate(WelcomeActivity.java:15) at android.app.Activity.performCreate(Activity.java:5990) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2311) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2420) at android.app.ActivityThread.access$900(ActivityThread.java:154) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5294) 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:904) at

com.android.internal.os.ZygoteInit.main (ZygoteInit.java:699) 03-24 10: 23: 27.498 4679-4690 / com.gobonus.gobonus W / art: Suspending all threads flow: 26.757ms Request.java:

 package com.gobonus.gobonus;

 import java.io.BufferedReader;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.ProtocolException;
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;


 public class Request {

     private final String USER_AGENT = "GoBonus Android Client 1.0";
     private final String API_SERVER = "http://192.168.2.21";

     public String Content;


     public Request (String session_token, String uri, String params) {

         String urlParameters = "session_token =" + session_token + "&" + params;  // url params
         byte [] postData = new byte [0];

         System.setProperty ("http.agent", USER_AGENT);  // user agent truck

         // api = android.os.Build.VERSION_CODES.KITKAT) {
             postData = urlParameters.getBytes (StandardCharsets.UTF_8);
         }
         else
             postData = urlParameters.getBytes (Charset.forName ("UTF-8"));

         int postDataLength = postData.length;
         URL url = null;

         try {
             url = new URL (API_SERVER + uri);
         } catch (MalformedURLException e) {
             e.printStackTrace ();
         }
         HttpURLConnection conn = null;
         try {
             conn = (HttpURLConnection) url.openConnection ();
         } catch (IOException e) {
             e.printStackTrace ();
         }
         conn.setDoOutput (true);
         conn.setInstanceFollowRedirects (false);
         try {
             conn.setRequestMethod ("POST");
         } catch (ProtocolException e) {
             e.printStackTrace ();
         }
         conn.setRequestProperty ("Content-Type", "application / x-www-form-urlencoded");
         conn.setRequestProperty ("charset", "utf-8");
         conn.setRequestProperty ("Content-Length", Integer.toString (postDataLength));

         conn.setUseCaches (false);
         try {
             DataOutputStream wr = new DataOutputStream (conn.getOutputStream ());
             wr.write (postData);
             conn.connect ();
             Content = ConvertData (conn);
         } catch (IOException e) {
             e.printStackTrace ();
         }
     }
     protected String ConvertData (HttpURLConnection url) throws IOException {
         // local variables
         String line;
         StringBuffer text = new StringBuffer ();

         InputStreamReader in = new InputStreamReader ((InputStream) url.getContent ());
         BufferedReader buff = new BufferedReader (in);
         do {
             line = buff.readLine ();
             text.append (line + "\ n");
         } while (line! = null);
         return text.toString ();
     }

 }

WelcomeActivity.java

 package com.gobonus.gobonus;

 import android.content.Intent;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.TextView;

 public class WelcomeActivity extends AppCompatActivity {

     @Override
     protected void onCreate (Bundle savedInstanceState) {
         super.onCreate (savedInstanceState);
         TextView WebTest = (TextView) findViewById (R.id.webTest);
         WebTest.setText (new Request ("123", "/ ajax", "foo = bar"). Content);
         setContentView (R.layout.activity_welcome);
     }

     public void LoginGo (View view) {
         Intent intent = new Intent (WelcomeActivity.this, LoginActivity.class);
         startActivity (intent);
     }
 }

Manifesto

 <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.gobonus.gobonus"> <!-- To auto-complete the email text field in the login form with the user's emails --> <uses-permission android:name="android.permission.GET_ACCOUNTS" /> <uses-permission android:name="android.permission.READ_PROFILE" /> <uses-permission android:name="android.permission.READ_CONTACTS" /> <uses-permission android:name="android.permission.INTERNET" /> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/GB"> <activity android:name=".WelcomeActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".LoginActivity" android:label="@string/title_activity_login" android:parentActivityName=".WelcomeActivity"> <meta-data android:name="android.support.PARENT_ACTIVITY" android:value="com.gobonus.gobonus.WelcomeActivity" /> </activity> </application> </manifest>

Layout

 <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.gobonus.gobonus.WelcomeActivity"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/sign" android:id="@+id/button" android:background="#B6B6B6" android:layout_marginBottom="162dp" android:onClick="LoginGo" android:layout_alignParentBottom="true" android:layout_alignRight="@+id/button2" android:layout_alignEnd="@+id/button2" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/reg" android:id="@+id/button2" android:background="#B6B6B6" android:layout_alignTop="@+id/button" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_marginTop="82dp" android:layout_alignParentRight="true" android:layout_alignParentEnd="true" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="New Text" android:id="@+id/webTest" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:layout_marginTop="56dp" /> </RelativeLayout>
  • 3
    Possible duplicate question: NetworkOnMainThreadException Exception - Vladyslav Matviienko
  • four
    There is such a thing called search . Have you tried? Great stuff! - Vladyslav Matviienko
  • four
    I'm afraid you're wrong, the problem is that the person directly referred to the doInBackground method, and I didn't even have AsyncTask . - blits

1 answer 1

NetworkOnMainThreadException indicates that you are using network requests in the main thread, use AsyncTask to run the request in a separate thread from the UI.

And the setContentView Method, needs to be called before you access the markup elements.

  @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_welcome); TextView WebTest = (TextView) findViewById(R.id.webTest); WebTest.setText(new Request("123", "/ajax", "foo=bar").Content); }

UPD

Sample request through AsyncTask . The doInBackground method runs in a separate thread from the UI , after you have completed the request and received a response, your data will drop into onPostExecute , which is already running in the UI stream. Do not access the UI thread in doInBackground , will cause Exception .

 public class WelcomeActivity extends AppCompatActivity { TextView WebTest; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_welcome); WebTest = (TextView) findViewById(R.id.webTest); new AsyncRequest().execute("123", "/ajax", "foo=bar"); } class AsyncRequest extends AsyncTask<String, Integer, String>{ @Override protected String doInBackground(String... arg) { return new Request(arg[0], arg[1], arg[2]).Content; } @Override protected void onPostExecute(String s) { super.onPostExecute(s); WebTest.setText(s); } } }