I am making an application that allows me to scan QR codes, and I managed to make the code work but my doubt is that when I scan the plugin phonegap-plugin-barcodescanner takes me out of the camera interface, what I want to do is to stay in it and show me an alert with the scanned code, and to give it ok in the alert to stay in it, to avoid being clicked to enter it.
I'm working with the plugin phonegap-plugin-barcodescanner, in ionic 3
public scanQR2() {
this._ButtonText = "Escanear";
this._barcodeScanner.scan().then((barcodeData) => {
if (barcodeData.cancelled) {
console.log("User cancelled the action!");
this._ButtonText = "Escanear";
return false;
}
console.log("Scanned successfully!");
console.log(barcodeData);
}, (err) => {
console.log(err);
});
}
I hope that the application when performing a scan stays on the same interface and does not redirect me to another page
Related
I'm building a PWA using Web Bluetooth API. Connection is OK, I set an eventlistener for getting data and when my Arduino with BLE module HM10 send data, I get them.
But my PWA has more than one page. So on first one I have a "Connection" button, and after connection I "listen".
When I go to a second page, I use navigator.bluetooth.getDevices() to get previsouly connected device.
But I get an empty list.
I though my getDevices() function was bugged but I discoverd a strange thing:
my PWA run a browser tab on Chrome. I connect to the device. Then, on another tab I open this url with a Google example (https://googlechrome.github.io/samples/web-bluetooth/get-devices.html) and call Get Bluetooth Devices to get list of connected device, I see my device in this example page.
Without closing this second tab, I use my PWA: all page are able to get the device (using navigator.bluetooth.getDevices()), set the even and get data from the Arduino. Great!
If I close this tab, connection is lost...
So I think my "connection" is not perfect and when I close my PWA first page, I loose it... But as example avaible on internet are about "one page", I'm a bit lost (like the device connection in fact...).
Here is the code I use:
function reconnect_ble()
{
console.log('Search previously connected devices...');
navigator.bluetooth.getDevices()
.then(devices => {
console.log('> Got ' + devices.length + ' Bluetooth devices.');
if (devices.length == 0)
{
alert("No module");
return false;
}
var flag_module = false;
for (const device of devices)
{
var nom = device.name;
// Check if it's our modle
if (nom == pwa_hm10)
{
flag_module = connectToBluetoothDevice(device);
}
}
if (flag_module == false)
{
alert("Nothing for us");
return false;
}
else
{
return true;
}
})
.catch(error => {
console.log('Erreur:' + error);
});
}
//===================================================================================
// First Connection
function connect_ble()
{
return (deviceCache ? Promise.resolve(deviceCache) :
requestBluetoothDevice()).
then(device => connectToBluetoothDevice(device)).
catch(error => display_info(error));
}
//-------------------------------------------------------------------------------------
function connectToBluetoothDevice(device)
{
const abortController = new AbortController();
// Evenement sur ce device
device.addEventListener('advertisementreceived', (event) =>
{
console.log('connectToBluetoothDevice- Advertisements from "' + device.name + '"...');
// Stop watching advertisements to conserve battery life.
abortController.abort();
// Connexion au serveur GATT
device.gatt.connect()
.then(() =>
{
console.log('connectToBluetoothDevice - Server GATT from "' + device.name + '"...');
// Set our event
connectDeviceAndCacheCharacteristic(device).
then(characteristic => startNotifications(characteristic)).
catch(error => display_info(error));
})
.catch(error =>
{
// Erreur pas de connexion
console.log(error);
});
}, { once: true });
console.log('connectToBluetoothDevice - Watching advertisements from "' + device.name + '"...');
device.watchAdvertisements({ signal: abortController.signal })
.catch(error =>
{
console.log(error);
});
}
//----------------------------------------------------------------------------------
// Form to choose device
function requestBluetoothDevice()
{
return navigator.bluetooth.requestDevice(
{
acceptAllDevices: true,
optionalServices: [0xFFE0]
}).
then(device => {
display_info('Selected: ' + device.name);
deviceCache = device;
deviceCache.addEventListener('gattserverdisconnected',handleDisconnection);
return deviceCache;
});
}
//-----------------------------------------------------------------------------------
function connectDeviceAndCacheCharacteristic(device)
{
if (device.gatt.connected && characteristicCache)
{
return Promise.resolve(characteristicCache);
}
return device.gatt.connect().
then(server => {
return server.getPrimaryService(0xFFE0);
}).
then(service => {
return service.getCharacteristic(0xFFE1);
}).
then(characteristic => {
display_info('characteristic founded');
characteristicCache = characteristic;
return characteristicCache;
});
}
//------------------------------------------------------------------------------------
function startNotifications(characteristic)
{
return characteristic.startNotifications().
then(() => {
characteristic.addEventListener('characteristicvaluechanged',handleCharacteristicValueChanged);
});
}
//--------------------------------------------------------------------------------------
function handleCharacteristicValueChanged(event)
{
// Decoding received data
var decodage = new TextDecoder().decode(event.target.value);
traitement_data_ble(decodage);
}
Edit
If you connect to the bluetooth on Page 1, and go to Page 2 on same tab, connection is lost.
If you connect to the bluetooth on Page 1, set an event listenner to get data then open Page 2 on another tab, Page 2 will "see" the bluetooth module, but even if Page 2 set an event listener, this is even from Page 1 that will receive the data.
If you connect to the bluetooth on Page 1, don't set event listenner, open Page 2 in other tab and set event listenner on Page 2, Page 2 will receive the data.
So case 3 seems to be the only way. Maybe using iFrame for the connection page??
Accessing the same device from multiple pages is not supported and the fact that it seems to partially work is more of a bug than a feature. A device can't effectively distinguish between multiple pages on the same host trying to communicate with it so you need to have a single piece of code which manages the connection to the device.
The correct way to do this today is to create a single-page application so that the connection held by that page can remain own even if the user navigates to different "pages" of your application. If you need to create separate windows these can communicate with the device by sending commands back through the single page that owns the connection using postMessage or Broadcast Channel.
The ideal solution, which is not currently supported, is to use a Shared Worker for this. Shared Workers are a type of web worker which is owned by all the currently open pages of your app at once. It can thus hold shared state (such as the Bluetooth connection) in behalf of your application and won't exit unless every window of your app is closed.
so in ionic 3 there was registerBackButton() but in ionic 4 this option is no longer there and has been sitting on the shelf for quite some time now.
I have read the post here that tries to solve the solution I am looking for, however, the back button still performs as it wants to.
this SO answer shows another way but it is the same idea of intercepting and navigating, however, I am just, for now, trying to dismiss the top modal in the stack.
scenario: users open a search modal(modal1) which then they click on a users profile modal(modal2). The person wants to go back to the search modal(modal1) but instead of clicking the nice button that allows them to do that, they use the hardware back button.
result: all modals(modal1 and modal2) are closed.
desired effect: using the hardware back button will allow for custom navigation based on logic in place.
attempted code:
this.platform.backButton.subscribeWithPriority(0, (): void => {
this.modalCtrl.getTop().then(
async (value: HTMLIonModalElement): Promise<void> => {
if (!!value) {
await this.modalCtrl.dismiss();
} else {
this.navCtrl.navigateRoot('/home');
}
},
);
});
also have tried :
// registering back, if there is a view on top, close it, don't go to home.
this.platform.backButton.subscribeWithPriority(0, async (): Promise<void>=> {
try {
console.log('try');
const element = await this.modalCtrl.getTop();
if (element) {
console.log('in true');
await element.dismiss();
}
} catch (error) {
console.log('error closing modal', error);
}
});
note when pressing the back button I never see ANY of the console logs... maybe things have changed a lot more? since the previous Stack overflow questions.
UPDATE:
If you are having this same issue then know you are not alone!
This, and many others are well known, see here for a list they are tracking the issues. Nothing else to do... but wait... I guess...
I will update this when there is a change
I am developing an app in Xamarin.Forms, before I was trying to make a master detail page to become my MainPage when I logged in to my app, this I have already achieved. Now I have the problem that when I use the button behind the phone my app is miimiza and goes to the background which is the behavior I hope, but when I return to my app does not continue showing my master detail page, but returns to my LginPage.
It is as if my app was running twice or at least there were two instances of LoginPage existing at the same time, this is because in my LoginPage I trigger some DisplayAlert according to some messages that my page is listening through the MessaginCenter and they are they shoot twice.
Can someone tell me how I can return the same to my app on the master detail page and not restart in the strange way described?
LoginView.xaml.cs:
public partial class LogonView : ContentPage
{
LogonViewModel contexto = new LogonViewModel();
public LogonView ()
{
InitializeComponent ();
BindingContext = contexto;
MessagingCenter.Subscribe<LogonViewModel>(this, "ErrorCredentials", async (sender) =>
{
await DisplayAlert("Error", "Email or password is incorrect.", "Ok");
}
);
}
protected override void OnDisappearing()
{
base.OnDisappearing();
MessagingCenter.Unsubscribe<LogonViewModel>(this, "ErrorCredentials");
}
}
Part of my ViewModel:
if (Loged)
{
App.token = token;
Application.Current.MainPage = new RootView();
}
else
{
MessagingCenter.Send(this, "ErrorCredentials");
}
Thanks.
I hope this is in Android. All you can do is, you can override the backbuttonpressed method in MainActivity for not closing on back button pressed of the entry page. like below, you can add some conditions as well.
public override void OnBackPressed()
{
Page currentPage = Xamarin.Forms.Application.Current.MainPage.Navigation.NavigationStack.LastOrDefault();
if (currentPage != null)
{
if (currentPage.GetType().Name == "HomePage" || currentPage.GetType().Name == "LoginPage")
{
return;
}
}
base.OnBackPressed();
}
When you press the Home button, the application is paused and the
current state is saved, and finally the application is frozen in
whatever state it is. After this, when you start the app, it is
resumed from the last point it was saved with.
However, when you use the Back button, you keep traversing back in
the activity stack, closing one activity after another. in the end,
when you close the first activity that you opened, your application
exits. This is why whenever you close your application like this, it
gets restarted when you open it again.
Answer taken from this answer. The original question asks about the native Android platform, but it still applies here.
It means you have to Use Setting Plugin or save data in Application properties.
You have to add below code in App.xaml.cs file:
if (SettingClass.UserName == null)
MainPage = new LoginPage();
else
MainPage = new MasterDetailPage();
For Setting Plugin you can refer this link.
I am using Ionic 2 and would like to kill the page from feather loading similar to PHP die(); function
Below is the method that I currently working with.
fetch_data() {
let loader = this.loadingCtrl.create({ content: 'Loading...' });
loader.present();
this.bank.types().subscribe( response => {
this.linkBankTypes = response.results;
loader.dismiss();
}, err => {
loader.dismiss();
loader = this.loadingCtrl.create({ content: 'No Internet connection. Make sure Wi-Fi or cellular data is turned on, then try again.' });
//Kill the page from here
});
}
PHP's die() function stops creation of the page and lets PHP run environment to return a nasty error message to the client browser.
You can cause the Ionic to crash by throwing exceptions, but that is not a pleasant user experience and not recommended.
Instead you either navigate to an error page or show a message indicating the error.
The NavController's push or popcan be used to navigate to an error page or back to the previous page.
i am just trying to implement facebook and twitter in my Webworks App and cannot get them work together.
I am using the FaceBook-OAuth-2 and the Twitter-OAuth-1 sample and i just put both stuff together and my problem is that only the first startOAuth() opens a window in the app to login the second doesn't so if i first clicked facebook it works after when i try twitter nothing happens.
https://github.com/blackberry/BB10-WebWorks-Samples
thanks
function setClickHandlers() {
console.log('set click handlers');
var fb = document.getElementById('facebookOn');
fb.addEventListener('click', function(e) {
// if the childWindow is already open, don't allow user to click the button
if(childWindow !== null) {
return false;
}
e.preventDefault();
toast('Contacting Facebook...');
setTimeout(function() {
startOAuth();
}, 500);
});
console.log('set twitter click handlers');
var tw = document.getElementById('twitterOn');
tw.addEventListener('click', function(e) {
// if the childWindow is already open, don't allow user to click the button
if(childWindow !== null) {
return false;
}
e.preventDefault();
toast('Fetching access token...');
setTimeout(function() {
twittergetAccessToken();
}, 500);
});
}
I would start by adding some debug code in your click handler to see if that's getting called when you click the button in the first place.
If it is, then I recommended you use Web Inspector (console) to see if there are any errors. If there are, they'll show up there.
Good reference for Web Inspector here - http://developer.blackberry.com/html5/documentation/web_inspector_overview_1553586_11.html
If the click handler is not being fired then perhaps you have the wrong element ID, or the setClickHandlers function is not being executed.