Develop Reference

Is there a way to check the connect ability of a BLE device in Xamarin.Forms (Plugin.BLE)?

Is there a way to check the connect ability of a BLE device in Xamarin.Forms (I'm using Plugin.BLE)? I need a method (similar to isConnactable) that will check the connect ability of each element from the ObservableCollection. I'm developing an Android application, so cross-platform is not necessary.
Sample illustration in code:
ObservableCollection<IDevice> DevicesList = new ObservableCollection<IDevice>();
ObservableCollection<IDevice> IsConnactableDevicesList = new ObservableCollection<IDevice>();
DevicesList = new ObservableCollection<IDevice>();
IsConnactableDevicesList = IfDeviceConnactable(DevicesList);

Do you mean the connectable property sent in the advertising packet? (i.e. https://developer.android.com/reference/android/bluetooth/le/ScanResult#isConnectable()). It seems your chosen library does not expose that info. You can skip the plugin and call the native Android framework directly to get this working, since you don't need cross platform compatibility anyway.
You can also modify the plugin to make it expose this info.

Allow user to access wifi settings without giving free reign

We are developing a locked down "kiosk-style" Android app on a stock Samsung tablet, which is mounted in customer vehicles. We would like to be able to allow customers to edit their wifi settings, without giving them access to the rest of the Settings app (e.g. Launcher, accounts, etc)
We have been able to launch the Wifi Settings activity, but it allows the user to go into other areas.
I'm not sure whether it's possible to create a custom interface for connecting to wifi, but even if it were possible, this seems fragile and a lot of work for something quite simple.
Is there any way to solve this well?

I would create a device policy controller app that is provisioned on the device as a device owner using Android Enterprise (Android for Work) APIs.
https://developers.google.com/android/work/dpc/build-dpc
As a device owner, you can set your app in lock task mode which is generally used for kiosks.
https://developer.android.com/work/cosu.html
Then, you can set user restrictions:
addUserRestriction api
user restrictions list
The user restrictions don't cover everything in the settings app, but the coverage is pretty good.
Then I would provision it using NFC or QR code reader from the Google Setup Wizard welcome screen.
https://github.com/googlesamples/android-NfcProvisioning
You might want to also look at existing open source EMM/MDM implementations that already exist such as WSO2.
Other references:
How to enable task locking in Android 5.0 production devices
How to make sure there is only one app

I was also working on Kiosk Type applications and we have to give options for Change wifi and Display Settings So we have used these commands on Button click for Wifi And Display
Settings
btnWifiSetting.setOnClickListener {
startActivityForResult( Intent(android.provider.Settings.ACTION_WIFI_SETTINGS), 0);
}
And For Display Setting
btnDisplay.setOnClickListener {
startActivityForResult(Intent(android.provider.Settings.ACTION_DISPLAY_SETTINGS),0)
}
And you can also check the full list of Available Commands here
https://ourcodeworld.com/articles/read/318/how-to-open-android-settings-programmatically-with-java

try LineAgeOS
https://lineageos.org/
Your requirement needs to access OS System level, this way you have access and customize the WIFI settings before releasing the phone itself

can you try this way.
WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
if (wifiManager.isWifiEnabled()) {
wifiManager.setWifiEnabled(false);
Tools_WiFi.setImageResource(R.drawable.tool_wifi_off);
} else {
wifiManager.setWifiEnabled(true);
Tools_WiFi.setImageResource(R.drawable.tool_wifi_on);
}

You can try this:
startActivityForResult(new Intent(Settings.ACTION_WIFI_SETTINGS), 0);
Hope it helps you.

Unity : Detect if mobile is on Tether connection

Short question: I want to check if the Personal Hotspot functionality is turned on
I am currently building a client/server application. I would like to know if my mobile (Android for instance) has tether connection activated (personal hotspot), since my server could connect to it.
I found how to detect wifi connection thanks to this answer Unity check internet connection availability but this does not detect if I am using tether connection.
Do you know how ?
Thanks you all !
ps : I don't need to know if I have an internet connection, just tether wifi working on

So you want to check if the Personal Hotspot functionality is turned on? That would only allow you to determine if other devices can use your device to connect to the internet. To do that from within an Android app on the device, you would use the WiFiManager class as shown here.
Do you want to tell if something is actually connected to the hotspot? If so, you can look at this source (specifically in the getClientList method) to check for connected clients.
You mention a server. Are you trying to run a server on a desktop / laptop computer and then connect it to the personal hotspot on the device, then have the mobile app connect to some server on the desktop? If so, there are other things you'll need to consider.

Thanks to wottle links and help, I manage to find the solution
public bool isWifiApEnabled()
{
using (AndroidJavaObject activity = new AndroidJavaClass("com.unity3d.player.UnityPlayer").GetStatic<AndroidJavaObject>("currentActivity"))
{
try
{
using (var wifiManager = activity.Call<AndroidJavaObject>("getSystemService", "wifi"))
{
return wifiManager.Call<bool>("isWifiApEnabled");
}
}
catch (System.Exception e)
{
}
}
return false;
}

How to use wifi as 3G/2G on Android?

There are some code on Android:
if(netType == NetType.3G ||netType == NetType.2G)
{
//do something
}
So I need use 3G/2G to test this code. But for security reason . I can only reach this if statement when I using the specific WIFI.
So is there any way to use WIFI and let code looks it as 3G/2G?

You can use the android emulator. With the emulator you can simulate various network connections.

Android JellyBean and P2P support

I am analysing Android JellyBean 4.3 source code.I could find the varialbe p2p_supported in HAL layer for Wi-Fi Direct support. In the below code snippet from wifi_ath.c
int wifi_start_supplicant(int p2p_supported)
{
if (p2p_supported)
{
strcpy(supplicant_name, P2P_SUPPLICANT_NAME);
strcpy(supplicant_prop_name, P2P_PROP_NAME); // for P2P support
.......................
}
else {
strcpy(supplicant_name, SUPPLICANT_NAME);
strcpy(supplicant_prop_name, SUPP_PROP_NAME); //for station support
}
The values of the macros are:
P2P_SUPPLICANT_NAME = p2p_supplicant ,P2P_PROP_NAME= init.svc.p2p_supplicant
SUPPLICANT_NAME=wpa_supplicant ,SUPP_PROP_NAME=init.svc.wpa_supplicant
Even while connecting in station mode the if part is getting executed and I could not make the WiFi up. Where in the code exactly p2p_supported variable is enabled and disabled so that both the P2P and Wi-Fi works smoothly?

From Jelly Bean(4.1) you only need to turn WiFi on to use WiFi Direct functionality, though using both together depends upon whether your chip supports it.(For that see this SO question)