feat: show warning if user tries to switch apps during LN receive

src/AppOnboarded.tsx

@@ -60,6 +60,8 @@ const AppOnboarded = (): ReactElement => {
 		const appStateSubscription = AppState.addEventListener(
 			'change',
 			(nextAppState) => {
+				dispatch(updateUi({ appState: nextAppState }));
+
 				// on App to foreground
 				if (
 					appState.current.match(/inactive|background/) &&

src/screens/Wallets/Receive/ReceiveQR.tsx

@@ -41,6 +41,7 @@ import { createLightningInvoice } from '../../../store/utils/lightning';
 import { updatePendingInvoice } from '../../../store/slices/metadata';
 import { generateNewReceiveAddress } from '../../../store/actions/wallet';
 import {
+	appStateSelector,
 	isLDKReadySelector,
 	viewControllerIsOpenSelector,
 } from '../../../store/reselect/ui';
@@ -93,6 +94,7 @@ const ReceiveQR = ({
 	const addressType = useAppSelector(addressTypeSelector);
 	const isGeoBlocked = useAppSelector(isGeoBlockedSelector);
 	const isLDKReady = useAppSelector(isLDKReadySelector);
+	const appState = useAppSelector(appStateSelector);
 	const { id, amount, message, tags, jitOrder } =
 		useAppSelector(receiveSelector);
 	const lightningBalance = useLightningBalance(false);
@@ -244,6 +246,16 @@ const ReceiveQR = ({
 		dispatch,
 	]);
 
+	useEffect(() => {
+		if (receiveNavigationIsOpen && enableInstant && appState !== 'active') {
+			showToast({
+				type: 'error',
+				title: t('receive_foreground_title'),
+				description: t('receive_foreground_msg'),
+			});
+		}
+	}, [t, appState, enableInstant, receiveNavigationIsOpen]);
+
 	const uri = useMemo((): string => {
 		if (!receiveNavigationIsOpen) {
 			return '';

src/store/reselect/ui.ts

@@ -110,3 +110,5 @@ export const fromAddressViewerSelector = createSelector(
 	[uiState],
 	(ui) => ui.fromAddressViewer,
 );
+
+export const appStateSelector = createSelector([uiState], (ui) => ui.appState);

src/store/shapes/ui.ts

@@ -43,4 +43,5 @@ export const initialUiState: TUiState = {
 	viewControllers: defaultViewControllers,
 	fromAddressViewer: false, // When true, ensures tx inputs are not cleared when sweeping from address viewer.
 	paymentMethod: 'onchain',
+	appState: 'active',
 };

src/store/types/ui.ts

@@ -1,3 +1,4 @@
+import { AppStateStatus } from 'react-native';
 import { LNURLWithdrawParams, LNURLPayParams } from 'js-lnurl';
 import { EActivityType, TOnchainActivityItem } from './activity';
 import { ReceiveStackParamList } from '../../navigation/bottom-sheet/ReceiveNavigation';
@@ -91,4 +92,5 @@ export type TUiState = {
 	language: string;
 	fromAddressViewer: boolean;
 	paymentMethod: 'onchain' | 'lightning';
+	appState: AppStateStatus;
 };

src/utils/i18n/locales/en/wallet.json

@@ -686,5 +686,13 @@
 	},
 	"receive_insufficient_text": {
 		"string": "Insufficient receiving capacity to receive this amount over Lightning."
+	},
+	"receive_foreground_title": {
+		"string": "Keep Bitkit In Foreground",
+		"developer_comment": "This message appears when the user is shown an LN invoice but tries to switch to another app"
+	},
+	"receive_foreground_msg": {
+		"string": "Payments to your spending balance might fail if you switch between apps.",
+		"developer_comment": "This message appears when the user is shown an LN invoice but tries to switch to another app"
 	}
 }