这适用于Q之前和之后的Android设备

fun isWifiConnected(context: Context):Boolean {
    val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
             val capabilities = cm.getNetworkCapabilities(cm.activeNetwork)
             capabilities?.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)==true
        } else {
            val activeNetwork: NetworkInfo? = cm.activeNetworkInfo
            activeNetwork?.typeName?.contains("wifi",ignoreCase = true)?:false
        }
}

我简单地使用以下方法:

SupplicantState supState; 
wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
supState = wifiInfo.getSupplicantState();

它将在调用getSupplicantState()时返回这些状态之一;

ASSOCIATED - Association completed. ASSOCIATING - Trying to associate with an access point. COMPLETED - All authentication completed. DISCONNECTED - This state indicates that client is not associated, but is likely to start looking for an access point. DORMANT - An Android-added state that is reported when a client issues an explicit DISCONNECT command. FOUR_WAY_HANDSHAKE - WPA 4-Way Key Handshake in progress. GROUP_HANDSHAKE - WPA Group Key Handshake in progress. INACTIVE - Inactive state. INVALID - A pseudo-state that should normally never be seen. SCANNING - Scanning for a network. UNINITIALIZED - No connection.

从API级别29开始，NetworkInfo类以及相关的访问方法(如connectivitymanager# getNetworkInfo()和connectivitymanager# getActiveNetworkInfo())都已弃用。

文档现在建议人们使用ConnectivityManager。NetworkCallback API用于异步回调监控，或使用connectivitymanager# getNetworkCapabilities或connectivitymanager# getLinkProperties来同步访问网络信息

调用者应该使用ConnectivityManager。NetworkCallback API来了解连接变化，或切换到使用connectivitymanager# getNetworkCapabilities或connectivitymanager# getLinkProperties来同步获取信息。

要检查是否连接了WiFi，下面是我使用的代码:

科特林：

val connMgr = applicationContext.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager?
connMgr?: return false
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    val network: Network = connMgr.activeNetwork ?: return false
    val capabilities = connMgr.getNetworkCapabilities(network)
    return capabilities != null && capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
} else {
    val networkInfo = connMgr.activeNetworkInfo ?: return false
    return networkInfo.isConnected && networkInfo.type == ConnectivityManager.TYPE_WIFI
}

Java:

ConnectivityManager connMgr = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
if (connMgr == null) {
    return false;
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    Network network = connMgr.getActiveNetwork();
    if (network == null) return false;
    NetworkCapabilities capabilities = connMgr.getNetworkCapabilities(network);
    return capabilities != null && capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI);
} else {
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    return networkInfo.isConnected() && networkInfo.getType() == ConnectivityManager.TYPE_WIFI;
}

记住还要向Manifest文件添加ACCESS_NETWORK_STATE权限。

添加到JAVA:

public boolean CheckWifiConnection() {
        ConnectivityManager conMgr = (ConnectivityManager) getSystemService (Context.CONNECTIVITY_SERVICE);
        if (conMgr.getActiveNetworkInfo() != null
                && conMgr.getActiveNetworkInfo().isAvailable()
                && conMgr.getActiveNetworkInfo().isConnected()) {
            return true;
        } else {
            return false;
        }
    }

在Manifest文件中添加以下权限:

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

试试这个方法。

public boolean isInternetConnected() {
    ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    boolean ret = true;
    if (conMgr != null) {
        NetworkInfo i = conMgr.getActiveNetworkInfo();

        if (i != null) {
            if (!i.isConnected()) {
                ret = false;
            }

            if (!i.isAvailable()) {
                ret = false;
            }
        }

        if (i == null)
            ret = false;
    } else
        ret = false;
    return ret;
}

这种方法将有助于找到互联网连接是否可用。

这个问题有点老了，但我用的就是这个。要求最低api级别21也考虑到废弃的Networkinfo api。

boolean isWifiConn = false;
    ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        Network network = connMgr.getActiveNetwork();
        if (network == null) return false;
        NetworkCapabilities capabilities = connMgr.getNetworkCapabilities(network);
        if(capabilities != null && capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)){
            isWifiConn = true;
            Toast.makeText(context,"Wifi connected Api >= "+Build.VERSION_CODES.M,Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(context,"Wifi not connected Api >= "+Build.VERSION_CODES.M,Toast.LENGTH_LONG).show();
        }
    } else {
        for (Network network : connMgr.getAllNetworks()) {
            NetworkInfo networkInfo = connMgr.getNetworkInfo(network);
            if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI && networkInfo.isConnected()) {
                isWifiConn = true;
                Toast.makeText(context,"Wifi connected ",Toast.LENGTH_LONG).show();
                break;
            }else{
                Toast.makeText(context,"Wifi not connected ",Toast.LENGTH_LONG).show();
            }
        }
    }
    return isWifiConn;