fix: downloading backups in mobile webview (#1703)

packages/web/src/javascripts/NativeMobileWeb/DownloadBlobOnAndroid.tsx

@@ -0,0 +1,28 @@
+import { WebApplication } from '@/Application/Application'
+import { getBase64FromBlob } from '@/Utils'
+import { Platform } from '@standardnotes/snjs'
+import { addToast, ToastType, dismissToast } from '@standardnotes/toast'
+
+export const downloadBlobOnAndroid = async (application: WebApplication, blob: Blob, filename: string) => {
+  if (!application.isNativeMobileWeb() || application.platform !== Platform.Android) {
+    throw new Error('Download function being used on non-android platform')
+  }
+  const loadingToastId = addToast({
+    type: ToastType.Loading,
+    message: `Downloading ${filename}..`,
+  })
+  const base64 = await getBase64FromBlob(blob)
+  const downloaded = await application.mobileDevice.downloadBase64AsFile(base64, filename)
+  if (downloaded) {
+    dismissToast(loadingToastId)
+    addToast({
+      type: ToastType.Success,
+      message: `Downloaded ${filename}`,
+    })
+  } else {
+    addToast({
+      type: ToastType.Error,
+      message: `Could not download ${filename}`,
+    })
+  }
+}