Question

我想创建一个使用互联网的应用程序，我正在尝试创建一个检查连接是否可用的功能，如果不可用，请转到具有重试按钮和解释的活动。

到目前为止附件是我的代码，但我收到错误Syntax error, insert "}" to complete MethodBody.

现在我一直在努力让它发挥作用，但到目前为止还没有运气......任何帮助都会受到赞赏。

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();
            }
        }
    }

Answer 1

此方法检查移动设备是否已连接到互联网，如果已连接则返回true：

private boolean isNetworkConnected() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    return cm.getActiveNetworkInfo() != null;
}

清单中的

，

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

修改此方法实际检查设备是否连接到互联网（有可能它连接到网络但不连接到互联网）。

public boolean isInternetAvailable() { try { InetAddress ipAddr = InetAddress.getByName("google.com"); //You can replace it with your name return !ipAddr.equals(""); } catch (Exception e) { return false; } }

Answer 2

检查以确保它“连接”到网络：

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

检查以确保它“连接”到网络：

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

需要许可：

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

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

Answer 3

您只需ping一个在线网站，例如google：

for (int i = 0; i < Array.Count - 1; i++)
{
    for (int j = (i + 1); j < Array.Count; j++)
    {
         ans.Add(Array.ElementAt(i) + Array.ElementAt(j));     

    }
}

Answer 4

当您连接到Wi-Fi源或通过手机数据包时，上述方法可以正常工作。但是在Wi-Fi连接的情况下，有些情况下您会被要求在Cafe中登录。因此，在这种情况下，当您连接到Wi-Fi源而不是Internet时，您的应用程序将会失败。

此方法正常。

    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;

}

请在主线程的单独线程中使用它，因为它进行网络调用，如果不跟随，将抛出NetwrokOnMainThreadException。

并且也不要将此方法放在onCreate或任何其他方法中。把它放在一个类中并访问它。

Answer 5

接受的答案的编辑显示了如何检查是否可以访问互联网上的内容。如果不是这样的话，我不得不等待太久的答案（没有互联网连接的wifi）。不幸的是，InetAddress.getByName没有超时参数，因此下一个代码可以解决这个问题：

private boolean internetConnectionAvailable(int timeOut) {
    InetAddress inetAddress = null;
    try {
        Future<InetAddress> future = Executors.newSingleThreadExecutor().submit(new Callable<InetAddress>() {
            @Override
            public InetAddress call() {
                try {
                    return InetAddress.getByName("google.com");
                } catch (UnknownHostException e) {
                    return null;
                }
            }
        });
        inetAddress = future.get(timeOut, TimeUnit.MILLISECONDS);
        future.cancel(true);
    } catch (InterruptedException e) {
    } catch (ExecutionException e) {
    } catch (TimeoutException e) {
    } 
    return inetAddress!=null && !inetAddress.equals("");
}

Answer 6

您无法在其他方法中创建方法，将private boolean checkInternetConnection() {方法移出onCreate

Answer 7

您可以使用以下代码段来检查Internet连接。

您可以通过两种方式检查网络的类型连接可用，因此您可以通过这种方式完成处理。

您只需要复制以下课程并直接粘贴到您的包中。

/**
 * 
 * @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;
    }
}

现在您可以使用：

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

不要忘记获取权限:)：）

<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" />

您可以根据自己的要求进行修改。

谢谢。

Answer 8

所有官方方法仅告知设备是否对网络开放，
如果你的设备连接到Wifi但Wifi没有连接到互联网，那么这些方法将失败（这种情况很多次发生），没有内置的网络检测方法会告诉这个场景，所以创建了Async Callback类，它将返回 onConnectionSuccess 和 onConnectionFail

        new CheckNetworkConnection(this, new CheckNetworkConnection.OnConnectionCallback() {

            @Override
            public void onConnectionSuccess() {
   Toast.makeText(context, "onSuccess()", toast.LENGTH_SHORT).show();
            }

            @Override
            public void onConnectionFail(String msg) {
   Toast.makeText(context, "onFail()", toast.LENGTH_SHORT).show();
            }
        }).execute();

来自异步任务的网络呼叫

public class CheckNetworkConnection extends AsyncTask<Void, Void, Boolean> {
private OnConnectionCallback onConnectionCallback;
private Context context;

public CheckNetworkConnection(Context con, OnConnectionCallback onConnectionCallback) {
     super();
     this.onConnectionCallback = onConnectionCallback;
    this.context = con;
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
}

@Override
protected Boolean doInBackground(Void... params) {
    if (context == null)
        return false;

    boolean isConnected = new NetWorkInfoUtility().isNetWorkAvailableNow(context);
    return isConnected;
}

@Override
protected void onPostExecute(Boolean b) {
    super.onPostExecute(b);

    if (b) {
        onConnectionCallback.onConnectionSuccess();
    } else {
        String msg = "No Internet Connection";
        if (context == null)
            msg = "Context is null";
        onConnectionCallback.onConnectionFail(msg);
    }

}

public interface OnConnectionCallback {
    void onConnectionSuccess();

    void onConnectionFail(String errorMsg);
}
}

将ping到服务器的实际类

class NetWorkInfoUtility {

public boolean isWifiEnable() {
    return isWifiEnable;
}

public void setIsWifiEnable(boolean isWifiEnable) {
    this.isWifiEnable = isWifiEnable;
}

public boolean isMobileNetworkAvailable() {
    return isMobileNetworkAvailable;
}

public void setIsMobileNetworkAvailable(boolean isMobileNetworkAvailable) {
    this.isMobileNetworkAvailable = isMobileNetworkAvailable;
}

private boolean isWifiEnable = false;
private boolean isMobileNetworkAvailable = false;

public boolean isNetWorkAvailableNow(Context context) {
    boolean isNetworkAvailable = false;

    ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

    setIsWifiEnable(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnected());
    setIsMobileNetworkAvailable(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnected());

    if (isWifiEnable() || isMobileNetworkAvailable()) {
        /*Sometime wifi is connected but service provider never connected to internet
        so cross check one more time*/
        if (isOnline())
            isNetworkAvailable = true;
    }

    return isNetworkAvailable;
}

public boolean isOnline() {
    /*Just to check Time delay*/
    long t = Calendar.getInstance().getTimeInMillis();

    Runtime runtime = Runtime.getRuntime();
    try {
        /*Pinging to Google server*/
        Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
        int exitValue = ipProcess.waitFor();
        return (exitValue == 0);
    } catch (IOException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    } finally {
        long t2 = Calendar.getInstance().getTimeInMillis();
        Log.i("NetWork check Time", (t2 - t) + "");
    }
    return false;
 }
}

Answer 9

无需复杂。最简单的框架方式是使用ACCESS_NETWORK_STATE权限并只创建一个连接的方法

public boolean isOnline() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnectedOrConnecting();
}

如果您有特定的主机和连接类型（wifi /移动设备），也可以使用requestRouteToHost。

您还需要：

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

在您的Android清单中。

了解更多详情go here

Answer 10

使用此方法：

public static boolean isOnline() {
    ConnectivityManager cm = (ConnectivityManager) context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    return netInfo != null && netInfo.isConnectedOrConnecting();
}

这是所需的许可：

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

Answer 11

请尝试以下代码：

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;
    }

Answer 12

清单中的

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

代码，

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;
}

Answer 13

public boolean checkInternetConnection(Context context) {
    ConnectivityManager connectivity = (ConnectivityManager) context
        .getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity == null) {
        return false;
    } else {
        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;
}

Answer 14

使用此代码检查互联网连接

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;
        }

Answer 15

在“return”语句之后，你不能写任何代码（不包括try-finally块）。在“返回”语句之前移动新的活动代码。

Answer 16

1-创建新的java文件（右键单击包.new＆gt; class＆gt;将文件命名为ConnectionDetector.java

2-将以下代码添加到文件

package <add you package name> example com.example.example;

import android.content.Context;
import android.net.ConnectivityManager;

public class ConnectionDetector {

    private Context mContext;

    public ConnectionDetector(Context context){
        this.mContext = context;
    }

    public boolean isConnectingToInternet(){

        ConnectivityManager cm = (ConnectivityManager)mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
        if(cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected() == true)
        {
            return true; 
        }

        return false;

    }
}

3-打开您的MainActivity.java - 要检查连接的活动，然后执行以下操作

创建并定义功能。

ConnectionDetector mConnectionDetector;</pre>

B-在＆＃34; OnCreate＆＃34;添加以下

mConnectionDetector = new ConnectionDetector(getApplicationContext());

c-检查连接使用以下步骤

if (mConnectionDetector.isConnectingToInternet() == false) {
//no connection- do something
} else {
//there is connection
}

Answer 17

我遇到的问题是IsInternetAvailable回答没有测试蜂窝网络，而只是连接了wifi。这个答案适用于wifi和移动数据：

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

Answer 18

使用互联网数据速度检查网络在Android中可用。

public boolean isConnectingToInternet(){
        ConnectivityManager connectivity = (ConnectivityManager) Login_Page.this.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)
                      {
                          try
                            {
                                HttpURLConnection urlc = (HttpURLConnection) (new URL("http://www.google.com").openConnection());
                                urlc.setRequestProperty("User-Agent", "Test");
                                urlc.setRequestProperty("Connection", "close");
                                urlc.setConnectTimeout(500); //choose your own timeframe
                                urlc.setReadTimeout(500); //choose your own timeframe
                                urlc.connect();
                                int networkcode2 = urlc.getResponseCode();
                                return (urlc.getResponseCode() == 200);
                            } catch (IOException e)
                            {
                                return (false);  //connectivity exists, but no internet.
                            }
                      }

          }
          return false;
    }

此函数返回true或false。必须获得用户许可

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

Answer 19

这是处理所有情况的另一种选择：

public void isNetworkAvailable() {
    ConnectivityManager connectivityManager = (ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
    if (activeNetworkInfo != null && activeNetworkInfo.isConnected()) {
    } else {
        Toast.makeText(ctx, "Internet Connection Is Required", Toast.LENGTH_LONG).show();

    }
}

Answer 20

这是一个我用作Utils类的一部分的函数：

public static boolean isNetworkConnected(Context context) {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    return (cm.getActiveNetworkInfo() != null) && cm.getActiveNetworkInfo().isConnectedOrConnecting();
}

使用它：Utils.isNetworkConnected(MainActivity.this);

Android检查互联网连接

20 个答案: