我不希望我的用户尝试下载任何东西，除非他们连接了Wi-Fi。然而，我似乎只能判断是否启用了Wi-Fi，但他们仍然可能有3G连接。
android.net.wifi.WifiManager m = (WifiManager) getSystemService(WIFI_SERVICE);
android.net.wifi.SupplicantState s = m.getConnectionInfo().getSupplicantState();
NetworkInfo.DetailedState state = WifiInfo.getDetailedStateOf(s);
if (state != NetworkInfo.DetailedState.CONNECTED) {
return false;
}
然而，这种状态并不是我所期望的。即使Wi-Fi是连接的，我得到OBTAINING_IPADDR作为状态。
当前回答
许多答案使用了废弃的代码，或者在更高API版本上可用的代码。现在我用这样的东西
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if(connectivityManager != null) {
for (Network net : connectivityManager.getAllNetworks()) {
NetworkCapabilities nc = connectivityManager.getNetworkCapabilities(net);
if (nc != null && nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
&& nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET))
return true;
}
}
return false;
其他回答
ConnectivityManager manager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
boolean is3g = manager.getNetworkInfo(
ConnectivityManager.TYPE_MOBILE).isConnectedOrConnecting();
boolean isWifi = manager.getNetworkInfo(
ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting();
Log.v("", is3g + " ConnectivityManager Test " + isWifi);
if (!is3g && !isWifi) {
Toast.makeText(
getApplicationContext(),
"Please make sure, your network connection is ON ",
Toast.LENGTH_LONG).show();
}
else {
// Put your function() to go further;
}
这是一个更简单的解决方案。参见Stack Overflow 在Android上检查是否启用Wi-Fi。
注:不要忘记将代码添加到manifest.xml文件中以允许权限。如下图所示。
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" >
</uses-permission>
由于方法NetworkInfo.isConnected()现在在API-23中已弃用，下面是一个方法，它可以检测Wi-Fi适配器是否打开，并使用WifiManager连接到接入点:
private boolean checkWifiOnAndConnected() {
WifiManager wifiMgr = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if (wifiMgr.isWifiEnabled()) { // Wi-Fi adapter is ON
WifiInfo wifiInfo = wifiMgr.getConnectionInfo();
if( wifiInfo.getNetworkId() == -1 ){
return false; // Not connected to an access point
}
return true; // Connected to an access point
}
else {
return false; // Wi-Fi adapter is OFF
}
}
使用WifiManager你可以做到:
WifiManager wifi = (WifiManager) getSystemService (Context.WIFI_SERVICE);
if (wifi.getConnectionInfo().getNetworkId() != -1) {/* connected */}
方法getNeworkId只有在没有连接到网络时才返回-1;
下面是我在我的应用程序中使用的实用方法:
public static boolean isDeviceOnWifi(final Context context) {
ConnectivityManager connManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
return mWifi != null && mWifi.isConnectedOrConnecting();
}
