How to check currently internet connection is avai

问题:

I want to execute my application offline also, so I need to check if currently an internet connection is available or not. Can anybody tell me how to check if internet is available or not in android? Give sample code. I tried with the code below and checked using an emulator but it's not working

public  boolean isInternetConnection() 
{ 

    ConnectivityManager connectivityManager =  (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
    return connectivityManager.getActiveNetworkInfo().isConnectedOrConnecting(); 
} 

Thanks

回答1:

This will tell if you're connected to a network:

boolean connected = false;
ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
    if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED || 
            connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
        //we are connected to a network
        connected = true;
    }
    else
        connected = false;

Warning: If you are connected to a WiFi network that doesn't include internet access or requires browser-based authentication, connected will still be true.

You will need this permission in your manifest:

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

回答2:

Also, be aware that sometimes the user will be connected to a Wi-Fi network, but that network might require browser-based authentication. Most airport and hotel hotspots are like that, so you application might be fooled into thinking you have connectivity, and then any URL fetches will actually retrieve the hotspot's login page instead of the page you are looking for.

Depending on the importance of performing this check, in addition to checking the connection with ConnectivityManager, I'd suggest including code to check that it's a working Internet connection and not just an illusion. You can do that by trying to fetch a known address/resource from your site, like a 1x1 PNG image or 1-byte text file.

回答3:

Use Below Code:

private boolean isNetworkAvailable() {
  ConnectivityManager connectivityManager 
      = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
  return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

if isNetworkAvailable() returns true then internet connection available, otherwise internet connection not available

Here need to add below uses-Permission in your application Manifest file

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

回答4:

You can just try to establish a TCP connection to a remote host:

public boolean hostAvailable(String host, int port) {
  try (Socket socket = new Socket()) {
    socket.connect(new InetSocketAddress(host, port), 2000);
    return true;
  } catch (IOException e) {
    // Either we have a timeout or unreachable host or failed DNS lookup
    System.out.println(e);
    return false;
  }
}

Then:

boolean online = hostAvailable("www.google.com", 80);

回答5:

use the next code:

public static boolean isNetworkAvaliable(Context ctx) {
    ConnectivityManager connectivityManager = (ConnectivityManager) ctx
            .getSystemService(Context.CONNECTIVITY_SERVICE);
    if ((connectivityManager
            .getNetworkInfo(ConnectivityManager.TYPE_MOBILE) != null && connectivityManager
            .getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED)
            || (connectivityManager
                    .getNetworkInfo(ConnectivityManager.TYPE_WIFI) != null && connectivityManager
                    .getNetworkInfo(ConnectivityManager.TYPE_WIFI)
                    .getState() == NetworkInfo.State.CONNECTED)) {
        return true;
    } else {
        return false;
    }
}

remember that yo need put in your manifest the next line:

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

回答6:

You can use two method :

1 - for check connection :

   private boolean isNetworkConnected() {
        ConnectivityManager cm = (ConnectivityManager) getContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        return cm.getActiveNetworkInfo() != null;
    }

2 - for check internet :

  public boolean internetIsConnected() {
        try {
            String command = "ping -c 1 google.com";
            return (Runtime.getRuntime().exec(command).waitFor() == 0);
        } catch (Exception e) {
            return false;
        }
    }

Add permissions to manifest :

 <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" />

回答7:

Use the method checkConnectivity:

  if (checkConnectivity()){
    //do something 

    }

Method to check your connectivity:

private boolean checkConnectivity() {
        boolean enabled = true;

        ConnectivityManager connectivityManager = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = connectivityManager.getActiveNetworkInfo();

        if ((info == null || !info.isConnected() || !info.isAvailable())) {
                            Toast.makeText(getApplicationContext(), "Sin conexión a Internet...", Toast.LENGTH_SHORT).show();
            return false;
        } else {
            return true;
        }

        return false;
    }

回答8:

package com.base64;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Base64;
import android.widget.ImageView;
import android.widget.Toast;

import com.androidquery.AQuery;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if(isConnectingToInternet(MainActivity.this))
        {
            Toast.makeText(getApplicationContext(),"internet is available",Toast.LENGTH_LONG).show();
        }
        else {
            System.out.print("internet is not available");
        }
    }

    public static boolean isConnectingToInternet(Context context)
    {
        ConnectivityManager connectivity =
                (ConnectivityManager) context.getSystemService(
                        Context.CONNECTIVITY_SERVICE);
        if (connectivity != null)
        {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null)
                for (int i = 0; i < info.length; i++)
                    if (info[i].getState() == NetworkInfo.State.CONNECTED)
                    {
                        return true;
                    }
        }
        return false;
    }
}

/*  manifest */

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.base64">

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

</manifest>

回答9:

try using ConnectivityManager

ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity != null) {
        NetworkInfo[] info = connectivity.getAllNetworkInfo();
        if (info != null) {
            for (int i = 0; i < info.length; i++) {
                if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                    return true;
                }
            }
        }
    }
 return false

Also Add permission to AndroidManifest.xml

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

回答10:

public boolean isOnline() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnectedOrConnecting()) {
        return true;
    } else {
        return false;
    }
}

Use this. Because device can be not connected to Internet even if it is connected to wifi. Wifi can be not connected to Internet

回答11:

public static   boolean isInternetConnection(Context mContext)
{
    ConnectivityManager connectivityManager = (ConnectivityManager)mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
    if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
            connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
        //we are connected to a network
        return  true;
    }
    else {
        return false;
    }
}

回答12:

Use ConnectivityManager Service

Source Link

...
...
import android.net.ConnectivityManager;
....
....
public class Utils {

   static ConnectivityManager connectivityManager;
   ....
   ....

    public static String isOnline(Context context) {
        JSONArray array = new JSONArray();
        JSONObject jsonObject = new JSONObject();
        try {
            jsonObject.put("connected","false");
        } catch (JSONException e) {
            e.printStackTrace();
        }
        try {
            connectivityManager = (ConnectivityManager) context
                    .getSystemService(Context.CONNECTIVITY_SERVICE);

            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            Log.i("networkInfo", networkInfo.toString());
            jsonObject.put("connected",(networkInfo != null && networkInfo.isAvailable() &&
                    networkInfo.isConnected()));
            jsonObject.put("isAvailable",(networkInfo.isAvailable()));
            jsonObject.put("isConnected",(networkInfo.isConnected()));
            jsonObject.put("typeName",(networkInfo.getTypeName()));
            array.put(jsonObject);
            return array.toString();


        } catch (Exception e) {
            System.out.println("CheckConnectivity Exception: " + e.getMessage());
            Log.v("connectivity", e.toString());
        }
        array.put(jsonObject);
        return array.toString();
    }

}

回答13:

  public  boolean isInternetConnection()
    {
        ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
        if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
                connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
            //we are connected to a network
            return  true;
        }
        else {
            return false;
        }
    }