Get IP address of Android device using API

Question

I am trying to get the IP address of the android device using an API from ipify. I tried using the API suggested in https://www.ipify.org/. It is simple.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.example.ramesh.getipaddress">
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity><!-- ATTENTION: This was auto-generated to add Google Play services to your project for
     App Indexing.  See https://g.co/AppIndexing/AndroidStudio for more information. -->
        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version"/>

    </application>

</manifest>



import android.net.Uri;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;


public void onClick(View v) {


        Log.i("Test", "End");

        new networkingTask().execute();

        //getContents("http://localhost:8080");


        Log.i("Error", "Error1");
    }

}

 class networkingTask extends AsyncTask<String, String,String> {
    protected String doInBackground(String... urls) {
        //now call your ipify method which is doing the networking or calling a method that might be doing the networkign

        //getContents("http://localhost:8080");

        getipify();

        return null;
    }

     public void getipify() {

        try (java.util.Scanner s = new java.util.Scanner(new java.net.URL("https://api.ipify.org").openStream(), "UTF-8").useDelimiter("\\A")) {
            System.out.println("My current IP address is " + s);
        } catch (java.io.IOException e) {
            System.out.println("======");
            System.out.println(e);
            System.out.println("======");

        }


         Log.i("Test","====TEST====");
     }

}

For some reason it wont open the stream. I get the error

java.lang.IllegalStateException: Could not execute method for android:onClick at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick

I have used this method in swift and it works just fine. I have looked at all other methods but this appears easy.

Error section from Android Studio: --------- beginning of crash E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.ramesh.getipaddress, PID: 2381 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ramesh.getipaddress/com.example.ramesh.getipaddress.MainActivity}: android.os.NetworkOnMainThreadException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) at android.app.ActivityThread.access$800(ActivityThread.java:151) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5254) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) Caused by: android.os.NetworkOnMainThreadException at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147) at java.net.InetAddress.lookupHostByName(InetAddress.java:418) at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)

Any help will be greatly appreciated.

Thanks

Ramesh

Answer 1

Going through your full code looks like your acitivty is crashing because you are attempting to perform a network call on the main thread. You must do the networking in a background thread. You can and should use async task to achieve this:

You code will look like this:

Update: For the second error: do this:

 // just make sure to replace button with the id of your button
 Button b = (Button) findViewById(R.id.button);

    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
        new networkingTask().execute();
        }
    });

public void onClick(View v) {

        Log.i("Test", "End");
        Log.i("Error", "Error1");

new networkingTask().execute();

    } 

//create a asynctask class:

private class networkingTask extends AsyncTask<String, String,String> {
     protected String doInBackground(String... urls) {
       //now call your ipify method which is doing the networking or calling a method that might be doing the networkign

        //getContents("http://localhost:8080");

                   getipify();

      return null;
     }

}