How to check bluetooth state in Ionic 4 - ionic-framework

Question

I am new with Ionic 4, I am trying to check the bluetooth state with #ionic-native/diagnostic, here is my code
app.module.ts
#NgModule({
declarations: [
MyApp,
HomePage,
CheckRegInfo
],
imports: [
BrowserModule,
HttpClientModule,
TranslateModule.forRoot({
loader: {
provide: TranslateLoader,
useFactory: (createTranslateLoader),
deps: [HttpClient]
}
}),
IonicModule.forRoot(MyApp)
],
bootstrap: [IonicApp],
entryComponents: [
MyApp,
HomePage,
CheckRegInfo
],
providers: [
StatusBar,
SplashScreen,
Diagnostic,
{provide: ErrorHandler, useClass: IonicErrorHandler}
]
})
export class AppModule {}
The checking function:
import { Component } from '#angular/core';
import {AlertController, NavController} from 'ionic-angular';
import {Diagnostic} from "#ionic-native/diagnostic/ngx";
#Component({
selector: 'page-check',
templateUrl: 'check.html'
})
export class CheckRegInfo {
logowhitesrc:string = "assets/imgs/logowhite.png";
constructor(public navCtrl: NavController, private alertController:AlertController, private diagnostic: Diagnostic) {
}
checkBluetoothState(){
let titleStr: string;
this.diagnostic.getBluetoothState()
.then((state) => {
if (state == this.diagnostic.bluetoothState.POWERED_ON){
titleStr = "Okay"
} else {
titleStr = "Not Okay"
}
}).catch(e => console.error(e));
let addAlert = this.alertController.create({
title:"Bluetooth state",
message:titleStr
});
addAlert.present();
}
}
But when I try this on the device, there is no response ? I try on the ionic serve -> it going to the error Object(...) is not a function

Answer 1

Try the following:
declare let cordova: any;
#Component({
selector: 'page-check',
templateUrl: 'check.html'
})
export class CheckRegInfo {
logowhitesrc : string = "assets/imgs/logowhite.png";
constructor(public navCtrl : NavController,
private alertController : AlertController,
private diagnostic : Diagnostic) {}
checkBluetoothState(){
let titleStr: string;
cordova.plugins.diagnostic.getBluetoothState().then((state) => {
if (state == cordova.plugins.diagnostic.bluetoothState.POWERED_ON){
titleStr = "Okay";
showAlert(titleStr);
} else {
titleStr = "Not Okay";
showAlert(titleStr);
}
}).catch(e => console.error(e));
}
showAlert(title){
let addAlert = this.alertController.create({
title :"Bluetooth state",
message:titleStr
});
addAlert.present();
}
According to the docs, you need to call it using cordova.plugins.diagnostic:
The core plugin module is exposed via the global cordova.plugins.diagnostic object and it aliases all functions and properties of the other optional modules.
Also, since then() is used for asynchronous operation, therefore you need to call the method showAlert(titleStr) inside of .then().