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
你可以打开WIFI，如果它没有被激活如下 1. 查看@Jason Knight回复的WIFI状态 2. 如果没有激活，请激活它 不要忘记在manifest文件中添加WIFI权限
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
您的Java类应该是这样的
public class TestApp extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//check WIFI activation
ConnectivityManager connManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (mWifi.isConnected() == false) {
showWIFIDisabledAlertToUser();
}
else {
Toast.makeText(this, "WIFI is Enabled in your devide", Toast.LENGTH_SHORT).show();
}
}
private void showWIFIDisabledAlertToUser(){
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setMessage("WIFI is disabled in your device. Would you like to enable it?")
.setCancelable(false)
.setPositiveButton("Goto Settings Page To Enable WIFI",
new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int id){
Intent callGPSSettingIntent = new Intent(
Settings.ACTION_WIFI_SETTINGS);
startActivity(callGPSSettingIntent);
}
});
alertDialogBuilder.setNegativeButton("Cancel",
new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int id){
dialog.cancel();
}
});
AlertDialog alert = alertDialogBuilder.create();
alert.show();
}
}
其他回答
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();
}
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;
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.
Try
wifiManager.getConnectionInfo().getIpAddress()
这将返回0，直到设备有一个可用的连接(在我的机器上，三星SM-T280, Android 5.1.1)。
