Android check internet connection [duplicate]

2018-12-31 07:18发布

This question already has an answer here:

I want to create an app that uses the internet and I'm trying to create a function that checks if a connection is available and if it isn't, go to an activity that has a retry button and an explanation.

Attached is my code so far, but I'm getting the error Syntax error, insert "}" to complete MethodBody.

Now I have been placing these in trying to get it to work, but so far no luck... Any help would be appreciated.

public class TheEvoStikLeagueActivity extends Activity {
    private final int SPLASH_DISPLAY_LENGHT = 3000;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);

        private boolean checkInternetConnection() {
            ConnectivityManager conMgr = (ConnectivityManager) getSystemService (Context.CONNECTIVITY_SERVICE);
            // ARE WE CONNECTED TO THE NET
            if (conMgr.getActiveNetworkInfo() != null
                    && conMgr.getActiveNetworkInfo().isAvailable()
                    && conMgr.getActiveNetworkInfo().isConnected()) {

                return true;

                /* New Handler to start the Menu-Activity
                 * and close this Splash-Screen after some seconds.*/
                new Handler().postDelayed(new Runnable() {
                    public void run() {
                        /* Create an Intent that will start the Menu-Activity. */
                        Intent mainIntent = new Intent(TheEvoStikLeagueActivity.this, IntroActivity.class);
                        TheEvoStikLeagueActivity.this.startActivity(mainIntent);
                        TheEvoStikLeagueActivity.this.finish();
                    }
                }, SPLASH_DISPLAY_LENGHT);
            } else {
                return false;

                Intent connectionIntent = new Intent(TheEvoStikLeagueActivity.this, HomeActivity.class);
                TheEvoStikLeagueActivity.this.startActivity(connectionIntent);
                TheEvoStikLeagueActivity.this.finish();
            }
        }
    }

20条回答
浅入江南
2楼-- · 2018-12-31 07:49

Try the following code:

public static boolean isNetworkAvailable(Context context) {
        boolean outcome = false;

        if (context != null) {
            ConnectivityManager cm = (ConnectivityManager) context
                    .getSystemService(Context.CONNECTIVITY_SERVICE);

            NetworkInfo[] networkInfos = cm.getAllNetworkInfo();

            for (NetworkInfo tempNetworkInfo : networkInfos) {


                /**
                 * Can also check if the user is in roaming
                 */
                if (tempNetworkInfo.isConnected()) {
                    outcome = true;
                    break;
                }
            }
        }

        return outcome;
    }
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只若初见
3楼-- · 2018-12-31 07:50

in manifest

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

in code,

public static boolean isOnline(Context ctx) {
    if (ctx == null)
        return false;

    ConnectivityManager cm =
            (ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnectedOrConnecting()) {
        return true;
    }
    return false;
}
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梦寄多情
4楼-- · 2018-12-31 07:51

The above methods work when you are connected to a Wi-Fi source or via cell phone data packs. But in case of Wi-Fi connection there are cases when you are further asked to Sign-In like in Cafe. So in that case your application will fail as you are connected to Wi-Fi source but not with the Internet.

This method works fine.

    public static boolean isConnected(Context context) {
        ConnectivityManager cm = (ConnectivityManager)context
                .getSystemService(Context.CONNECTIVITY_SERVICE);

    NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
    if (activeNetwork != null && activeNetwork.isConnected()) {
        try {
            URL url = new URL("http://www.google.com/");
            HttpURLConnection urlc = (HttpURLConnection)url.openConnection();
            urlc.setRequestProperty("User-Agent", "test");
            urlc.setRequestProperty("Connection", "close");
            urlc.setConnectTimeout(1000); // mTimeout is in seconds
            urlc.connect();
            if (urlc.getResponseCode() == 200) {
                return true;
            } else {
                return false;
            }
        } catch (IOException e) {
            Log.i("warning", "Error checking internet connection", e);
            return false;
        }
    }

    return false;

}

Please use this in a separate thread from the main thread as it makes a network call and will throw NetwrokOnMainThreadException if not followed.

And also do not put this method inside onCreate or any other method. Put it inside a class and access it.

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ら面具成の殇う
5楼-- · 2018-12-31 07:52

Check to make sure it is "connected" to a network:

public boolean isNetworkAvailable(Context context) {
    final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
    return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
}

Check to make sure it is "connected" to a network:

public boolean isInternetAvailable() {
    try {
        final InetAddress address = InetAddress.getByName("www.google.com");
        return !address.equals("");
    } catch (UnknownHostException e) {
        // Log error
    }
    return false;
}

Permission needed:

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

https://stackoverflow.com/a/17583324/950427

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忆尘夕之涩
6楼-- · 2018-12-31 07:52

I had issues with the IsInternetAvailable answer not testing for cellular networks, rather only if wifi was connected. This answer works for both wifi and mobile data:

How to check network connection enable or disable in WIFI and 3G(data plan) in mobile?

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笑指拈花
7楼-- · 2018-12-31 07:54

You can use following snippet to check Internet Connection.

It will useful both way that you can check which Type of NETWORK Connection is available so you can do your process on that way.

You just have to copy following class and paste directly in your package.

/**
 * 
 * @author Pratik Butani
 * 
 */
public class InternetConnection {

    /** CHECK WHETHER INTERNET CONNECTION IS AVAILABLE OR NOT */
    public static boolean checkConnection(Context context) {
        final ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetworkInfo = connMgr.getActiveNetworkInfo();

        if (activeNetworkInfo != null) { // connected to the internet
            Toast.makeText(context, activeNetworkInfo.getTypeName(), Toast.LENGTH_SHORT).show();

            if (activeNetworkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
                // connected to wifi
                return true;
            } else if (activeNetworkInfo.getType() == ConnectivityManager.TYPE_MOBILE) {
                // connected to the mobile provider's data plan
                return true;
            }
        }
        return false;
    }
}

Now you can use like:

if (InternetConnection.checkConnection(context)) {
    // Its Available...
} else {
    // Not Available...
}

DON'T FORGET to TAKE Permission :) :)

<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" />

You can modify based on your requirement.

Thank you.

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