feat(android): support background scanning

android/app/src/main/AndroidManifest.xml

@@ -31,6 +31,13 @@
                 <category android:name="android.intent.category.DEFAULT" />
                 <data android:mimeType="text/plain" />
             </intent-filter>
+            <intent-filter>
+            <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
+            <category android:name="android.intent.category.DEFAULT"/>
+            <data android:scheme="https"
+                  android:host="nfc-demo.capawesome.io"
+                  android:pathPrefix="/home" />
+        </intent-filter>
 
         </activity>
 

src/app/core/services/capacitor/capacitor-nfc/capacitor-nfc.service.ts

@@ -7,14 +7,15 @@ import {
   TransceiveResult,
   WriteOptions,
 } from '@capawesome-team/capacitor-nfc';
-import { Observable, Subject } from 'rxjs';
+import { Observable, ReplaySubject, Subject } from 'rxjs';
 import { PlatformService } from '../../platform/platform.service';
 
 @Injectable({
   providedIn: 'root',
 })
 export class CapacitorNfcService {
   private readonly scannedTagSubject = new Subject<NfcTag>();
+  private readonly lastScannedTagSubject = new ReplaySubject<NfcTag>(1);
   private readonly sessionCanceledSubject = new Subject<void>();
   private readonly sessionErrorSubject = new Subject<string>();
 
@@ -24,19 +25,17 @@ export class CapacitorNfcService {
   ) {
     Nfc.removeAllListeners().then(() => {
       Nfc.addListener('nfcTagScanned', event => {
-        console.log('nfcTagScanned', { event });
         this.ngZone.run(() => {
           this.scannedTagSubject.next(event.nfcTag);
+          this.lastScannedTagSubject.next(event.nfcTag);
         });
       });
       Nfc.addListener('scanSessionCanceled', () => {
-        console.log('scanSessionCanceled');
         this.ngZone.run(() => {
           this.sessionCanceledSubject.next();
         });
       });
       Nfc.addListener('scanSessionError', event => {
-        console.log('scanSessionError', { event });
         this.ngZone.run(() => {
           this.sessionErrorSubject.next(event.message);
         });
@@ -48,6 +47,10 @@ export class CapacitorNfcService {
     return this.scannedTagSubject.asObservable();
   }
 
+  public get lastScannedTag$(): Observable<NfcTag> {
+    return this.lastScannedTagSubject.asObservable();
+  }
+
   public get sessionCanceled$(): Observable<void> {
     return this.sessionCanceledSubject.asObservable();
   }

src/app/core/services/nfc/nfc/nfc.service.ts

@@ -21,6 +21,10 @@ export class NfcService {
     return this.capacitorNfcService.scannedTag$;
   }
 
+  public get lastScannedTag$(): Observable<NfcTag> {
+    return this.capacitorNfcService.lastScannedTag$;
+  }
+
   public async startScanSession(): Promise<void> {
     const isSupported = await this.isSupported();
     if (!isSupported) {

src/app/core/services/router/router.service.ts

@@ -1,14 +1,20 @@
 import { Injectable } from '@angular/core';
-import { Router } from '@angular/router';
+import { NavigationExtras, Router } from '@angular/router';
 
 @Injectable({
   providedIn: 'root',
 })
 export class RouterService {
   constructor(private readonly router: Router) {}
 
-  public navigateToReadPage(): Promise<boolean> {
-    return this.router.navigate(['read']);
+  public navigateToReadPage(options?: {
+    showLastScannedTag?: boolean;
+  }): Promise<boolean> {
+    let extras: NavigationExtras = {};
+    if (options?.showLastScannedTag) {
+      extras.queryParams = { showLastScannedTag: 'true' };
+    }
+    return this.router.navigate(['read'], extras);
   }
 
   public navigateToWritePage(): Promise<boolean> {

src/app/modules/home/pages/home/home.page.ts

@@ -1,21 +1,49 @@
-import { ChangeDetectionStrategy, Component } from '@angular/core';
-import { DialogService, PlatformService, RouterService } from '@app/core';
+import { ChangeDetectionStrategy, Component, OnInit } from '@angular/core';
+import {
+  DialogService,
+  NfcService,
+  PlatformService,
+  RouterService,
+} from '@app/core';
+import { ViewDidEnter, ViewDidLeave } from '@ionic/angular';
+import { skipWhile } from 'rxjs';
 
 @Component({
   selector: 'app-home',
   templateUrl: './home.page.html',
   styleUrls: ['./home.page.scss'],
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class HomePage {
+export class HomePage implements OnInit, ViewDidEnter, ViewDidLeave {
   public readonly isNativePlatform = this.platformService.isNativePlatform();
 
+  private viewDidLeave = false;
+
   constructor(
     private readonly routerService: RouterService,
     private readonly platformService: PlatformService,
     private readonly dialogService: DialogService,
+    private readonly nfcService: NfcService,
   ) {}
 
+  public ngOnInit(): void {
+    this.nfcService.lastScannedTag$
+      .pipe(skipWhile(() => this.viewDidLeave))
+      .subscribe(() => {
+        void this.routerService.navigateToReadPage({
+          showLastScannedTag: true,
+        });
+      });
+  }
+
+  public ionViewDidEnter(): void {
+    this.viewDidLeave = false;
+  }
+
+  public ionViewDidLeave(): void {
+    this.viewDidLeave = true;
+  }
+
   public async navigateToReadPage(): Promise<void> {
     await this.routerService.navigateToReadPage();
   }

src/app/modules/read/pages/read/read.page.ts

@@ -1,8 +1,10 @@
 import { ChangeDetectionStrategy, Component } from '@angular/core';
+import { ActivatedRoute } from '@angular/router';
 import { NfcService, PlatformService } from '@app/core';
+import { NfcTag } from '@capawesome-team/capacitor-nfc';
 import { ViewDidEnter, ViewWillLeave } from '@ionic/angular';
 import { UntilDestroy, untilDestroyed } from '@ngneat/until-destroy';
-import { take } from 'rxjs';
+import { Observable, take } from 'rxjs';
 
 @UntilDestroy()
 @Component({
@@ -12,12 +14,21 @@ import { take } from 'rxjs';
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class ReadPage implements ViewDidEnter, ViewWillLeave {
-  public scannedTag$ = this.nfcService.scannedTag$;
+  public scannedTag$: Observable<NfcTag>;
+
+  private showLastScannedTag = false;
 
   constructor(
     private readonly nfcService: NfcService,
     private readonly platformService: PlatformService,
-  ) {}
+    private readonly activatedRoute: ActivatedRoute,
+  ) {
+    this.showLastScannedTag =
+      this.activatedRoute.snapshot.queryParams.showLastScannedTag === 'true';
+    this.scannedTag$ = this.showLastScannedTag
+      ? this.nfcService.lastScannedTag$
+      : this.nfcService.scannedTag$;
+  }
 
   public ionViewDidEnter(): void {
     this.nfcService.startScanSession();
@@ -30,7 +41,7 @@ export class ReadPage implements ViewDidEnter, ViewWillLeave {
 
   private subscribeToObservables(): void {
     if (this.platformService.isIos()) {
-      this.nfcService.scannedTag$
+      this.scannedTag$
         .pipe(take(1), untilDestroyed(this))
         .subscribe(() => this.nfcService.stopScanSession());
     }