kivy: make backups optional

electrum/gui/kivy/main_window.py

@@ -164,6 +164,10 @@ class ElectrumWindow(App):
     def on_use_rbf(self, instance, x):
         self.electrum_config.set_key('use_rbf', self.use_rbf, True)
 
+    android_backups = BooleanProperty(False)
+    def on_android_backups(self, instance, x):
+        self.electrum_config.set_key('android_backups', self.android_backups, True)
+
     use_change = BooleanProperty(False)
     def on_use_change(self, instance, x):
         if self.wallet:
@@ -1252,7 +1256,7 @@ class ElectrumWindow(App):
         if new_path:
             self.show_info(_("Backup saved:") + f"\n{new_path}")
         else:
-            self.show_error(_("Backup NOT saved. Backup directory or password not configured."))
+            self.show_error(_("Backup NOT saved. Backup directory not configured."))
 
     def export_private_keys(self, pk_label, addr):
         if self.wallet.is_watching_only():

electrum/gui/kivy/uix/dialogs/settings.py

@@ -89,6 +89,13 @@ Builder.load_string('''
                     title: _('Password')
                     description: _("Change wallet password.")
                     action: root.change_password
+                CardSeparator
+                SettingsItem:
+                    status: _('Yes') if app.android_backups else _('No')
+                    title: _('Backups') + ': ' + self.status
+                    description: _("Backup wallet to external storage.")
+                    message: _("If this option is checked, a backup of your wallet will be written to external storage everytime you create a new channel. Make sure your wallet is protected with a strong password before you enable this option.")
+                    action: partial(root.boolean_dialog, 'android_backups', _('Backups'), self.message)
 
                 # disabled: there is currently only one coin selection policy
                 #CardSeparator

electrum/util.py

@@ -441,8 +441,10 @@ def android_data_dir():
     return PythonActivity.mActivity.getFilesDir().getPath() + '/data'
 
 def get_backup_dir(config):
-    return android_backup_dir() if 'ANDROID_DATA' in os.environ else config.get('backup_dir')
-
+    if 'ANDROID_DATA' in os.environ:
+        return android_backup_dir() if config.get('android_backups') else None
+    else:
+        return config.get('backup_dir')
 
 def ensure_sparse_file(filename):
     # On modern Linux, no need to do anything.

electrum/wallet.py

@@ -264,11 +264,12 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
             self.db.write(self.storage)
 
     def save_backup(self):
+        backup_dir = get_backup_dir(self.config)
+        if backup_dir is None:
+            return
         new_db = WalletDB(self.db.dump(), manual_upgrades=False)
         new_db.put('is_backup', True)
-        new_path = os.path.join(get_backup_dir(self.config), self.basename() + '.backup')
-        if new_path is None:
-            return
+        new_path = os.path.join(backup_dir, self.basename() + '.backup')
         new_storage = WalletStorage(new_path)
         new_storage._encryption_version = self.storage._encryption_version
         new_storage.pubkey = self.storage.pubkey