50

我也想离线执行我的应用程序，所以我需要检查当前是否有可用的互联网连接。谁能告诉我如何检查 android 中是否有互联网可用？给出示例代码。我尝试使用下面的代码并使用模拟器进行检查，但它不起作用

public  boolean isInternetConnection() 
{ 

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

谢谢

4

21 回答 21

92

这将告诉您是否已连接到网络：

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;

警告：如果您连接到不包括互联网访问或需要基于浏览器的身份验证的 WiFi 网络，connected则仍然如此。

您将在清单中需要此权限：

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
于 2011-03-29T14:36:18.560 回答
16

您可以使用两种方法：

1 - 检查连接：

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

2 - 检查互联网：

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

向清单添加权限： 

 <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" />
于 2018-08-05T07:37:07.357 回答
15

此外，请注意，有时用户会连接到 Wi-Fi 网络，但该网络可能需要基于浏览器的身份验证。大多数机场和酒店热点都是这样，因此您的应用程序可能会误以为您已连接，然后任何 URL 获取实际上都会检索热点的登录页面，而不是您正在寻找的页面。

根据执行此检查的重要性，除了检查与 ConnectivityManager 的连接之外，我建议包含代码以检查它是否是有效的 Internet 连接，而不仅仅是一种错觉。您可以通过尝试从您的站点获取已知地址/资源来做到这一点，例如 1x1 PNG 图像或 1 字节文本文件。

于 2011-03-29T14:48:20.053 回答
12

使用下面的代码：

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

如果isNetworkAvailable()返回true则 Internet 连接可用，否则 Internet 连接不可用

这里需要在您的应用程序清单文件中添加以下使用权限

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
于 2013-10-17T17:52:33.327 回答
9 
public boolean isOnline() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnectedOrConnecting()) {
        return true;
    } else {
        return false;
    }
}

Google 推荐使用此代码块检查互联网连接。因为即使连接到 WiFi，设备也可能没有互联网连接。

于 2018-06-27T19:38:02.373 回答
8

API 29 已弃用。

getActiveNetworkInfo在 API 29 中已弃用。所以我们可以在下面的 29 中使用它。

Kotlin 中用于所有 API 的新代码

fun isNetworkAvailable(context: Context): Boolean {
    val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
   
    // For 29 api or above
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        val capabilities = connectivityManager.getNetworkCapabilities(connectivityManager.activeNetwork) ?: return false
        return when {
            capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) ->    true
            capabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) ->   true
            capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) ->   true
            else ->     false
         }
    }
    // For below 29 api
    else {
        if (connectivityManager.activeNetworkInfo != null && connectivityManager.activeNetworkInfo!!.isConnectedOrConnecting) {
            return true
        }
    }
    return false
}
于 2020-03-29T12:11:32.257 回答
4

代码 ：

    fun isInternetConnection(): Boolean {
    var returnVal = false
    thread {
        returnVal = try {
            khttp.get("https://www.google.com/")
            true
        }catch (e:Exception){
            false
        }
    }.join()
    return returnVal
}

摇篮：

implementation 'io.karn:khttp-android:0.1.0'

我使用khttp是因为它很容易使用。

因此，在上面的代码中，如果成功连接到 google.com，则返回 true，否则返回 false。

于 2021-06-01T10:05:13.473 回答
3

使用下一个代码：

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;
    }
}

请记住，您需要在清单中放入下一行：

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
于 2013-11-21T18:03:26.387 回答
3

您可以尝试建立与远程主机的 TCP 连接：

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;
  }
}

然后：

boolean online = hostAvailable("www.google.com", 80);
于 2016-02-26T09:28:38.907 回答
3

此代码用于检查所有 Android 版本（包括 Android 9.0 及更高版本）的网络可用性：

public static boolean isNetworkConnected(Context  context) {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = cm.getActiveNetworkInfo();
    // For 29 api or above
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        NetworkCapabilities capabilities = cm.getNetworkCapabilities(cm.getActiveNetwork());
        return capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) ||
                capabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) ||
                capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR);
    } else return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

不要忘记在清单中添加网络状态权限

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

另外，在方法之前添加 @SuppressWarnings("deprecation") 以避免 android studio deprecation 警告。

于 2020-12-11T05:17:06.293 回答
2

这是您可以使用的方法。这适用于所有 API。

    public boolean isConnected() {
        ConnectivityManager cm = (ConnectivityManager) getApplicationContext()
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (cm == null) {
            return false;
        }
        /* NetworkInfo is deprecated in API 29 so we have to check separately for higher API Levels */
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            Network network = cm.getActiveNetwork();
            if (network == null) {
                return false;
            }
            NetworkCapabilities networkCapabilities = cm.getNetworkCapabilities(network);
            if (networkCapabilities == null) {
                return false;
            }
            boolean isInternetSuspended = !networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_NOT_SUSPENDED);
            return networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
                    && networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
                    && !isInternetSuspended;
        } else {
            NetworkInfo networkInfo = cm.getActiveNetworkInfo();
            return networkInfo != null && networkInfo.isConnected();
        }
    }
于 2021-04-07T08:41:30.590 回答
1

这个功能很好用...

public void checkConnection()
    {
        ConnectivityManager connectivityManager=(ConnectivityManager)

                this.getSystemService(Context.CONNECTIVITY_SERVICE);


  NetworkInfo wifi=connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);


 NetworkInfo  network=connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);


        if (wifi.isConnected())
        {
           //Internet available

        }
        else if(network.isConnected())
        {
             //Internet available


        }
        else
        {
             //Internet is not available
        }
    }

将权限添加到 AndroidManifest.xml

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
于 2020-01-15T07:47:13.513 回答
1

你可以试试这个：

private boolean isConnectedToWifi(){
    ConnectivityManager cm = (ConnectivityManager) getApplication().getSystemService(Context.CONNECTIVITY_SERVICE);
    if(cm != null){    
        NetworkCapabilities nc = cm.getNetworkCapabilities(cm.getActiveNetwork());
        return nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI);
    }
    return false;
}
于 2021-01-25T06:37:02.983 回答
1 
public boolean isNetworkAvailable(Context context) {
    ConnectivityManager connectivityManager = (ConnectivityManager) context
            .getSystemService(context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connectivityManager
            .getActiveNetworkInfo();
    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}
于 2020-09-06T02:39:52.607 回答
1 
  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;
        }
    }
于 2018-07-30T08:56:43.520 回答
1

如果没有网络连接，这将显示一个对话框错误框

    ConnectivityManager connMgr = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

    if (networkInfo != null && networkInfo.isConnected()) {
        // fetch data
    } else {
        new AlertDialog.Builder(this)
            .setTitle("Connection Failure")
            .setMessage("Please Connect to the Internet")
            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                }
            })
            .setIcon(android.R.drawable.ic_dialog_alert)
            .show();
    }
于 2020-03-27T19:01:55.550 回答
1

使用方法 checkConnectivity：

  if (checkConnectivity()){
    //do something 

    }

检查连接的方法：

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;
    }
于 2016-04-20T18:06:27.420 回答
1

尝试使用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

还向 AndroidManifest.xml 添加权限

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
于 2016-02-26T13:18:55.140 回答
1 
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;
    }
}
于 2018-07-30T22:02:52.940 回答
0

使用ConnectivityManager服务

来源链接 

...
...
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();
    }

}
于 2018-12-20T09:22:07.860 回答
0 
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>
于 2016-09-05T10:44:50.070 回答