I try to implement a flutter code that will control NIR Spectrometer via BLE.
I have a very long protocol of service and characteristic uuid pair, and I actually did the same in ionic by just using the uuid pairs and it worked fine...
Is there a way in flutter to call read/write/notify with out do all the:
List<BluetoothService> services = await device.discoverServices();
services.forEach((service) {
// do something with service
for(BluetoothCharacteristic c in characteristics) {
// save the characteristic for latter usage if needed
}
});
something like:
c = BluetoothCharacteristic(device, service_uuid, characteristic_uuid); // why there is no constructor!!
It's going to make life more easy for me!
I finally gave up, also some services that I need don't do advertisement.. So I started to use the plugin flutter_reactive_ble which gives me this option
Related
I'm trying to set up notify so that my BLE with sensor can send data to my android phone. My embedded code is based off of the example for Custom HRM on Adafruit's site (https://learn.adafruit.com/bluefruit-nrf52-feather-learning-guide/custom-hrm ) and the code for flutter is based off flutter blue's example
for (final BluetoothService service in services) {
if(service.uuid == widget.serviceID){
for (final BluetoothCharacteristic characteristic in service.characteristics) {
if(characteristic.uuid == widget.charID) {
await characteristic.setNotifyValue(true);
characteristic.value.listen((value) {
print(value);
});
}
}
I keep getting this error:
Unhandled Exception: PlatformException(set_notification_error, could not locate CCCD descriptor for characteristic: 00002a24-0000-1000-8000-00805f9b34fb, null, null)
I tested my flutter code for every available characteristic in case my ID is wrong (it's not though). I also tried printing out all descriptors for that characteristic and found out there's none.
In the example adafruit code, we don't need to add any descriptors, we only need to do
characteristic.setProperties(CHR_PROPS_NOTIFY);
characteristic.setPermission(SECMODE_OPEN, SECMODE_NO_ACCESS);
Am I missing something? How can I fix this?
Solved: It was a hardware issue. Service and characteristic UUIDs weren't setting correctly. Tested on a new Feather nRF52 and everything is good.
I'd like to run tests that call multiple Cloud Functions in the emulator that make use of a mocked out external service (getstream.io). That means the mock would have to stay around across function invocations. Is something like this possible?
let mock = new SomethingMock();
exports.resetMock = functions.https.onCall((data, context) => {
mock = new SomethingMock();
});
exports.addActivity = functions.https.onCall(async (data, context) => {
await mock.addActivity(something);
});
exports.getActivities = functions.https.onCall((data, context) => {
// assumes addActivity has been called a few times
return mock.getActivities();
});
This page says gives no guarantees about preservation of global state in production, but says nothing about the emulator:
https://firebase.google.com/docs/functions/tips#use_global_variables_to_reuse_objects_in_future_invocations
The firebase emulator will neither guarantee the preservation of global state.
The answer is in the definition itself:
The Firebase Local Emulator Suite consists of individual service emulators built to accurately mimic the behavior of Firebase services. This means you can connect your app directly to these emulators to perform integration testing or QA without touching production data. They(emulatored firebase services) are built for accuracy, not performance or security, and are not appropriate to use in production.
Having said that, there is not much added value in having an emulator that does not return results as if the service was in production.
I have a project that scans a iBeacon, and i had also learned this plugin
I have also googled so many projects for that but can't get expected result.
Here i had some code that I write for scan a beacon
listenToBeaconEvents() {
this.events.subscribe("didRangeBeaconsInRegion", data => {
// update the UI with the beacon list
this.zone.run(() => {
let json = data.region;
console.log("-------Beacons-------" + JSON.stringify(json));
this.beacons.push({
uuid: JSON.stringify(json.uuid),
identifier: JSON.stringify(json.identifier),
typename: JSON.stringify(json.typeName)
});
});
}
But my question is if i don't have an UUID of particular beacon then how i can search the beacon?
Please Help me. Thanks.
On iOS you cannot find beacons without a particular UUID -- the platform simply does not allow you to do this. Android has no such restriction.
See this related question for a more detailed explanation:
iOS iBeacon: How to get all of proximityUUID programmatically?
I am building an app on nativescript+Angular2. I have downloaded the "nativescript-google-maps-sdk" plugin from npm. If I enable setMyLocationEnabled(true), I get the "my-location" button on the upper right corner of the screen and clicking it takes me to my actual location.
What I would like to do is to get these coordinates programmaticaly, because I will need them for other operations (markers, proximity values etc.).
Ran through their code, but couldn't find how they are getting this current location. gMap.getMyLocation() is deprecated, so I can't use that, based on what's written here: https://developers.google.com/android/reference/com/google/android/gms/maps/GoogleMap
We should be using FusedLocationProviderApi. If this plugin isn't using it, then how does it acquire current location?
Can anyone shed some light?
mapReady(args) {
console.log("Map Ready");
var gMap = args.gMap;
gMap.setMyLocationEnabled(true);
// gMap.getMyLocation(); deprecated
// need to get current location coordinates, somehow...
}
The nativescript-google-maps-sdk plugin doesn't support getting your location from the device.
You need to get the location from nativescript-geolocation ( you are already doing that) and then pass that to the google-map.
If you check the google-maps plugin's AndroidManifest.xml, it doesn't have the permission to access the device's location.
So, as it turns out, you can get your location from your device in 2 ways:
with built in android LocationManager
with google play services location module, which uses FusedLocationProviderApi which is built on default android LocationManager
The difference, from what I've read, is that the googles' version is more advanced - it switches from different location modes (gps, wifi) automatically and saves up your battery.
So, in order to use the googles' way, we need to:
Import google play services location module (+ means newest version):
dependencies {
compile 'com.google.android.gms:play-services-location:+'
}
Then initialise the play services API:
declare var com: any;
GoogleApiClient = com.google.android.gms.common.api.GoogleApiClient;
LocationServices = com.google.android.gms.location.LocationServices;
var dis = this; // writing in typescript, so this is reference to our current component where this code will lay
// Create an instance of GoogleAPIClient.
if (this.googleApiClient == null) {
this.googleApiClient = new dis.GoogleApiClient.Builder(application.android.context)
.addConnectionCallbacks(new dis.GoogleApiClient.ConnectionCallbacks({
onConnected: function() {
console.log("GoogleApiClient: CONNECTED");
}.bind(this),
onConnectionSuspended: function() {
console.log("GoogleApiClient: SUSPENDED");
}.bind(this)
}))
.addOnConnectionFailedListener(new dis.GoogleApiClient.OnConnectionFailedListener({
onConnectionFailed: function() {
console.log("GoogleApiClient: CONNECTION ERROR");
}.bind(this)
}))
.addApi(dis.LocationServices.API)
.build();
}
this.googleApiClient.connect();
I am trying to register to a "Device added/ Device removed" event using WMI. When I say device - I mean something in the lines of a Disk-On-Key or any other device that has files on it which I can access...
I am registering to the event, and the event is raised, but the EventType propery is different from the one I am expecting to see.
The documentation (MSDN) states : 1- config change, 2- Device added, 3-Device removed 4- Docking. For some reason I always get a value of 1.
Any ideas ?
Here's sample code :
public class WMIReceiveEvent
{
public WMIReceiveEvent()
{
try
{
WqlEventQuery query = new WqlEventQuery(
"SELECT * FROM Win32_DeviceChangeEvent");
ManagementEventWatcher watcher = new ManagementEventWatcher(query);
Console.WriteLine("Waiting for an event...");
watcher.EventArrived +=
new EventArrivedEventHandler(
HandleEvent);
// Start listening for events
watcher.Start();
// Do something while waiting for events
System.Threading.Thread.Sleep(10000);
// Stop listening for events
watcher.Stop();
return;
}
catch(ManagementException err)
{
MessageBox.Show("An error occurred while trying to receive an event: " + err.Message);
}
}
private void HandleEvent(object sender,
EventArrivedEventArgs e)
{
Console.WriteLine(e.NewEvent.GetPropertyValue["EventType"]);
}
public static void Main()
{
WMIReceiveEvent receiveEvent = new WMIReceiveEvent();
return;
}
}
Well, I couldn't find the code. Tried on my old RAC account, nothing. Nothing in my old backups. Go figure. But I tried to work out how I did it, and I think this is the correct sequence (I based a lot of it on this article):
Get all drive letters and cache
them.
Wait for the WM_DEVICECHANGE
message, and start a timer with a
timeout of 1 second (this is done to
avoid a lot of spurious
WM_DEVICECHANGE messages that start
as start as soon as you insert the
USB key/other device and only end
when the drive is "settled").
Compare the drive letters with the
old cache and detect the new ones.
Get device information for those.
I know there are other methods, but that proved to be the only one that would work consistently in different versions of windows, and we needed that as my client used the ActiveX control on a webpage that uploaded images from any kind of device you inserted (I think they produced some kind of printing kiosk).
Oh! Yup, I've been through that, but using the raw Windows API calls some time ago, while developing an ActiveX control that detected the insertion of any kind of media. I'll try to unearth the code from my backups and see if I can tell you how I solved it. I'll subscribe to the RSS just in case somebody gets there first.
Well,
u can try win32_logical disk class and bind it to the __Instancecreationevent.
You can easily get the required info
I tried this on my system and I eventually get the right code. It just takes a while. I get a dozen or so events, and one of them is the device connect code.