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
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
}
}
这适用于最新版本的android:
fun getConnectionType(context: Context): ConnectivityType {
var result = NONE
val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager?
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (cm != null) {
val capabilities = cm.getNetworkCapabilities(cm.activeNetwork)
if (capabilities != null) {
when {
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> {
result = WIFI
}
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> {
result = MOBILE_DATA
}
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_VPN) -> {
result = VPN
}
}
}
}
} else {
if (cm != null) {
val activeNetwork = cm.activeNetworkInfo
if (activeNetwork != null) {
// connected to the internet
when (activeNetwork.type) {
ConnectivityManager.TYPE_WIFI -> {
result = WIFI
}
ConnectivityManager.TYPE_MOBILE -> {
result = MOBILE_DATA
}
ConnectivityManager.TYPE_VPN -> {
result = VPN
}
}
}
}
}
return result
}
enum class ConnectivityType {
NONE,
MOBILE_DATA,
WIFI,
VPN,
}
在清单中:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
我在我的应用程序中使用这个来检查活动网络是否为Wi-Fi:
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo ni = cm.getActiveNetworkInfo();
if (ni != null && ni.getType() == ConnectivityManager.TYPE_WIFI)
{
// Do your work here
}
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;
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" />
