Query battery state on startup in iOS Platform Channel examples (#9437)

examples/platform_channel/ios/Runner/AppDelegate.m

@@ -55,6 +55,7 @@
                          eventReceiver:(FlutterEventReceiver)eventReceiver {
   _eventReceiver = eventReceiver;
   [[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];
+  [self sendBatteryStateEvent];
   [[NSNotificationCenter defaultCenter]
    addObserver:self
       selector:@selector(onBatteryStateDidChange:)
@@ -64,6 +65,10 @@
 }
 
 - (void)onBatteryStateDidChange:(NSNotification*)notification {
+  [self sendBatteryStateEvent];
+}
+
+- (void)sendBatteryStateEvent {
   if (!_eventReceiver) return;
   UIDeviceBatteryState state = [[UIDevice currentDevice] batteryState];
   switch (state) {
@@ -76,8 +81,8 @@
       break;
     default:
       _eventReceiver([FlutterError errorWithCode:@"UNAVAILABLE"
-                                          message:@"Charging status unavailable"
-                                          details:nil]);
+                                         message:@"Charging status unavailable"
+                                         details:nil]);
       break;
   }
 }

examples/platform_channel_swift/ios/Runner/AppDelegate.swift

@@ -47,6 +47,7 @@ import Flutter
                        eventReceiver: @escaping FlutterEventReceiver) -> FlutterError? {
     self.eventReceiver = eventReceiver;
     UIDevice.current.isBatteryMonitoringEnabled = true;
+    self.sendBatteryStateEvent();
     NotificationCenter.default.addObserver(
       self,
       selector: #selector(onBatteryStateDidChange),
@@ -56,6 +57,10 @@ import Flutter
   }
 
   @objc private func onBatteryStateDidChange(notification: NSNotification) {
+    self.sendBatteryStateEvent();
+  }
+
+  private func sendBatteryStateEvent() {
     if (eventReceiver == nil) {
       return;
     }