flutter_blue I/flutter (13169): Error starting scan.

Hello there, I added flutter_blue inside pubspec.yaml as:

dependencies:
  flutter:
    sdk: flutter
  flutter_blue: #0.6.3+1
    git:
      url: git://github.com/pauldemarco/flutter_blue.git

and added permissions inside android/app/src/main/AndroidManifest.xml as:

    package="com.amin.bluewatch">
    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
         calls FlutterMain.startInitialization(this); in its onCreate method.
         In most cases you can leave this as-is, but you if you want to provide
         additional functionality it is fine to subclass or reimplement
         FlutterApplication and put your custom class here. -->
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <application...

and in ios/Runner/info.plist as:

    <key>NSBluetoothAlwaysUsageDescription</key>
    <string>Need BLE permission</string>
    <key>NSBluetoothPeripheralUsageDescription</key>
    <string>Need BLE permission</string>
    <key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
    <string>Need Location permission</string>
    <key>NSLocationAlwaysUsageDescription</key>
    <string>Need Location permission</string>
    <key>NSLocationWhenInUseUsageDescription</key>
    <string>Need Location permission</string>

	<key>CFBundleDevelopmentRegion</key>...

and my scan test code went as:

floatingActionButton: FloatingActionButton(
        onPressed: () {

          FlutterBlue flutterBlue = FlutterBlue.instance;

          // Start scanning
          flutterBlue.startScan(timeout: Duration(seconds: 4));

          // Listen to scan results
           var subscription = flutterBlue.scanResults.listen((results) {
              
                // do something with scan results
                for (ScanResult r in results) {
                       
                       print('${r.device.name} found! rssi: ${r.rssi}');
                      
               }
          });

          // Stop scanning
          flutterBlue.stopScan();
        },
        child: Icon(Icons.search),
)

and below is the results I got inside the console...

D/BluetoothAdapter(23833): stopLeScan()
D/BluetoothAdapter(23833): startLeScan(): [Ljava.util.UUID;@41fba538
I/flutter (23833): Error starting scan.
E/flutter (23833): [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: PlatformException(startScan, getBluetoothLeScanner() is null. Is the Adapter on?, java.lang.IllegalStateException: getBluetoothLeScanner() is null. Is the Adapter on?
E/flutter (23833): 	at com.pauldemarco.flutter_blue.FlutterBluePlugin.startScan18(FlutterBluePlugin.java:850)
E/flutter (23833): 	at com.pauldemarco.flutter_blue.FlutterBluePlugin.startScan(FlutterBluePlugin.java:751)
E/flutter (23833): 	at com.pauldemarco.flutter_blue.FlutterBluePlugin.onMethodCall(FlutterBluePlugin.java:255)
E/flutter (23833): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:230)
E/flutter (23833): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:85)
E/flutter (23833): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:692)
E/flutter (23833): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/flutter (23833): 	at android.os.MessageQueue.next(MessageQueue.java:138)
E/flutter (23833): 	at android.os.Looper.loop(Looper.java:123)
E/flutter (23833): 	at android.app.ActivityThread.main(ActivityThread.java:5584)
E/flutter (23833): 	at java.lang.reflect.Method.invokeNative(Native Method)
E/flutter (23833): 	at java.lang.reflect.Method.invoke(Method.java:515)
E/flutter (23833): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
E/flutter (23833): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
E/flutter (23833): 	at dalvik.system.NativeStart.main(Native Method)
E/flutter (23833): )
E/flutter (23833): #0      FlutterBlue.scan (package:flutter_blue/src/flutter_blue.dart:124:7)
E/flutter (23833): <asynchronous suspension>
E/flutter (23833): #1      FlutterBlue.startScan (package:flutter_blue/src/flutter_blue.dart:162:11)
E/flutter (23833): #2      _BlueWatchState.build.<anonymous closure> (package:bluewatch/main.dart:95:23)
E/flutter (23833): #3      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:992:19)
E/flutter (23833): #4      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:1098:38)
E/flutter (23833): #5      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:184:24)
E/flutter (23833): #6      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:524:11)
E/flutter (23833): #7      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:284:5)
E/flutter (23833): #8      BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:219:7)
E/flutter (23833): #9      PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:477:9)
E/flutter (23833): #10     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:78:12)
E/flutter (23833): #11     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:124:9)
E/flutter (23833): #12     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)
E/flutter (23833): #13     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:122:18)
E/flutter (23833): #14     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:108:7)
E/flutter (23833): #15     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:220:19)
E/flutter (23833): #16     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:200:22)
E/flutter (23833): #17     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:158:7)
E/flutter (23833): #18     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:104:7)
E/flutter (23833): #19     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:88:7)
E/flutter (23833): #20     _rootRunUnary (dart:async/zone.dart:1206:13)
E/flutter (23833): #21     _CustomZone.runUnary (dart:async/zone.dart:1100:19)
E/flutter (23833): #22     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1005:7)
E/flutter (23833): #23     _invoke1 (dart:ui/hooks.dart:267:10)
E/flutter (23833): #24     _dispatchPointerDataPacket (dart:ui/hooks.dart:176:5)
E/flutter (23833):

I wonder what I am messing, or missing here to have it not working on my side?

Aug 25 '20 10:08 Amin-Matola

Hello, I Have the same issue !

Sep 04 '20 23:09 javiervalero31

I got similar issue.

E/flutter ( 5034): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: PlatformException(error, Field devices_ for b.c.a.u not found. Known fields are [private b.b.a.b0$i b.c.a.u.e, private static final b.c.a.u b.c.a.u.f, private static volatile b.b.a.a1 b.c.a.u.g], null, java.lang.RuntimeException: Field devices_ for b.c.a.u not found. Known fields are [private b.b.a.b0$i b.c.a.u.e, private static final b.c.a.u b.c.a.u.f, private static volatile b.b.a.a1 b.c.a.u.g]
E/flutter ( 5034): 	at b.b.a.v0.a(Unknown Source:72)
E/flutter ( 5034): 	at b.b.a.v0.a(Unknown Source:715)
E/flutter ( 5034): 	at b.b.a.v0.a(Unknown Source:12)
E/flutter ( 5034): 	at b.b.a.k0.a(Unknown Source:60)
E/flutter ( 5034): 	at b.b.a.k0.a(Unknown Source:49)
E/flutter ( 5034): 	at b.b.a.d1.a(Unknown Source:17)
E/flutter ( 5034): 	at b.b.a.d1.a(Unknown Source:4)
E/flutter ( 5034): 	at b.b.a.z.m(Unknown Source:4)
E/flutter ( 5034): 	at b.b.a.z$a.a(Unknown Source:9)
E/flutter ( 5034): 	at b.b.a.z$a.b(Unknown Source:0)
E/flutter ( 5034): 	at b.c.a.b.onMethodCall(Unknown Source:1336)
E/flutter ( 5034): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(Unknown Source:17)
E/flutter ( 5034): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(Unknown Source:57)
E/flutter ( 5034): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(Unknown Source:4)
E/flutter ( 5034): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/flutter ( 5034): 	at android.os.MessageQueue.next(MessageQueue.java:336)
E/flutter ( 5034): 	at android.os.Looper.loop(Looper.java:174)
E/flutter ( 5034): 	at android.app.ActivityThread.main(ActivityThread.java:7397)
E/flutter ( 5034): 	at java.lang.reflect.Method.invoke(Native Method)
E/flutter ( 5034): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
E/flutter ( 5034): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935)
E/flutter ( 5034): )
E/flutter ( 5034): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:582)
E/flutter ( 5034): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:159)
E/flutter ( 5034): <asynchronous suspension>
E/flutter ( 5034): #2      FlutterBlue.connectedDevices.<anonymous closure> (package:flutter_blue/src/flutter_blue.dart:72)
E/flutter ( 5034): <asynchronous suspension>
E/flutter ( 5034): 
I/flutter ( 5034): Error starting scan.
E/flutter ( 5034): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: PlatformException(startScan, Field androidScanMode_ for b.c.a.s0 not found. Known fields are [private int b.c.a.s0.e, private b.b.a.b0$i b.c.a.s0.f, private boolean b.c.a.s0.g, private static final b.c.a.s0 b.c.a.s0.h, private static volatile b.b.a.a1 b.c.a.s0.i], java.lang.RuntimeException: Field androidScanMode_ for b.c.a.s0 not found. Known fields are [private int b.c.a.s0.e, private b.b.a.b0$i b.c.a.s0.f, private boolean b.c.a.s0.g, private static final b.c.a.s0 b.c.a.s0.h, private static volatile b.b.a.a1 b.c.a.s0.i]
E/flutter ( 5034): 	at b.b.a.v0.a(Unknown Source:72)
E/flutter ( 5034): 	at b.b.a.v0.a(Unknown Source:715)
E/flutter ( 5034): 	at b.b.a.v0.a(Unknown Source:12)
E/flutter ( 5034): 	at b.b.a.k0.a(Unknown Source:60)
E/flutter ( 5034): 	at b.b.a.k0.a(Unknown Source:49)
E/flutter ( 5034): 	at b.b.a.d1.a(Unknown Source:17)
E/flutter ( 5034): 	at b.b.a.d1.a(Unknown Source:4)
E/flutter ( 5034): 	at b.b.a.z$a.a(Unknown Source:9)
E/flutter ( 5034): 	at b.b.a.z$a.a(Unknown Source:4)
E/flutter ( 5034): 	at b.b.a.z$a.a(Unknown Source:0)
E/flutter ( 5034): 	at b.b.a.a$a.a(Unknown Source:2)
E/flutter ( 5034): 	at b.c.a.b.a(Unknown Source:10)
E/flutter ( 5034): 	at b.c.a.b.onMethodCall(Unknown Source:1414)
E/flutter ( 5034): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(Unknown Source:17)
E/flutter ( 5034): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(Unknown Source:57)
E/flutter ( 5034): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(Unknown Source:4)
E/flutter ( 5034): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/flutter ( 5034): 	at android.os.MessageQueue.next(MessageQueue.java:336)
E/flutter ( 5034): 	at android.os.Looper.loop(Looper.java:174)
E/flutter ( 5034): 	at android.app.ActivityThread.main(ActivityThread.java:7397)
E/flutter ( 5034): 	at java.lang.reflect.Method.invoke(Native Method)
E/flutter ( 5034): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
E/flutter ( 5034): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935)
E/flutter ( 5034): , null)
E/flutter ( 5034): #0      FlutterBlue.scan (package:flutter_blue/src/flutter_blue.dart:124)
E/flutter ( 5034): <asynchronous suspension>
E/flutter ( 5034): <asynchronous suspension>
E/flutter ( 5034):

$ugifractal avatar$ Nov 14 '20 08:11 ugifractal

I have the same issue as above. However, the problem only happens when I install a release build of my application. If I install the debug build, it works fine:

I/FlutterBluePlugin(28742): setup I/flutter (28742): Error starting scan. E/flutter (28742): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: PlatformException(startScan, Field androidScanMode_ for b.b.a.s0 not found. Known fields are [private int b.b.a.s0.e, private b.a.a.b0$i b.b.a.s0.f, private boolean b.b.a.s0.g, private static final b.b.a.s0 b.b.a.s0.h, private static volatile b.a.a.a1 b.b.a.s0.i], java.lang.RuntimeException: Field androidScanMode_ for b.b.a.s0 not found. Known fields are [private int b.b.a.s0.e, private b.a.a.b0$i b.b.a.s0.f, private boolean b.b.a.s0.g, private static final b.b.a.s0 b.b.a.s0.h, private static volatile b.a.a.a1 b.b.a.s0.i] E/flutter (28742): at b.a.a.v0.a(Unknown Source:72) E/flutter (28742): at b.a.a.v0.a(Unknown Source:715) E/flutter (28742): at b.a.a.v0.a(Unknown Source:12) E/flutter (28742): at b.a.a.k0.a(Unknown Source:60) E/flutter (28742): at b.a.a.k0.a(Unknown Source:49) E/flutter (28742): at b.a.a.d1.a(Unknown Source:17) E/flutter (28742): at b.a.a.d1.a(Unknown Source:4) E/flutter (28742): at b.a.a.z$a.a(Unknown Source:9) E/flutter (28742): at b.a.a.z$a.a(Unknown Source:4) E/flutter (28742): at b.a.a.z$a.a(Unknown Source:0) E/flutter (28742): at b.a.a.a$a.a(Unknown Source:2) E/flutter (28742): at b.b.a.b.b(Unknown Source:10) E/flutter (28742): at b.b.a.b.a(Unknown Source:1414) E/flutter (28742): at c.a.c.a.j$a.a(Unknown Source:17) E/flutter (28742): at io.flutter.embedding.engine.e.b.a(Unknown Source:57) E/flutter (28742): at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(Unknown Source:4) E/flutter (28742): at android.os.MessageQueue.nativePollOnce(Native Method) E/flutter (28742): at android.os.MessageQueue.next(MessageQueue.java:336) E/flutter (28742): at android.os.Looper.loop(Looper.java:174) E/flutter (28742): at android.app.ActivityThread.main(ActivityThread.java:7386) E/flutter (28742): at java.lang.reflect.Method.invoke(Native Method) E/flutter (28742): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) E/flutter (28742): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980) E/flutter (28742): , null) E/flutter (28742): #0 FlutterBlue.scan (package:flutter_blue/src/flutter_blue.dart:124) E/flutter (28742): E/flutter (28742): E/flutter (28742):

Nov 20 '20 04:11 spekary

I fixed this issue on release build by disable shrinkResources at android/app/build.gradle

buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
            shrinkResources false
            minifyEnabled false
            //proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

$ugifractal avatar$ Nov 20 '20 04:11 ugifractal

Neither

shrinkResources false

Nor

minifyEnabled false

worked for me.

This is on Android 8.1.0.

Nov 20 '20 04:11 spekary

flutter build apk --no-shrink worked for me.

Nov 20 '20 08:11 gksrb4

Hello flutter_blue team, We are also facing the same Issue

The problem only happens when I install a release build of my application. If I install the debug build, it works fine:

buildTypes {
        release {
            signingConfig signingConfigs.debug
            shrinkResources false
            minifyEnabled false
        }
    }

Fixed this issue on release build by disabling shrink resources and minifyEnabled at android/app/build.gradle

But It's strange as It's disabling ProGuard. So what about android apk file source securities.

So It must need a proactive solution for the same for It should work with ProGuard enable.

Highly appreciate your answer to this thread Thank you!

Dec 09 '20 11:12 dhaval-volansys

I just completely excluded flutter blue classes in proguard rules.

-keep class com.pauldemarco.flutter_blue.** { *; }

Dec 17 '20 19:12 igorczapski

I was skeptic but the ProGuard rule helped!

Dec 28 '20 06:12 MrCsabaToth

are there any updates on this issue? disable shrinking solves it but is unconvenient

Jul 01 '21 10:07 nicolosponziello

are there any updates on this issue? disable shrinking solves it but is unconvenient

Add the ProGuard rules (creating the file if you don't have one already). Minimum these rules:

-keep class com.pauldemarco.flutter_blue.** { *; }
-keepclassmembernames class com.pauldemarco.flutter_blue.* { *; }

This is not a Flutter Blue specific problem. For more rules see this blog post: https://csaba.page/blog/flutter-android-crash-remedies.html

Jul 01 '21 17:07 MrCsabaToth

Merhaba flutter_blue ekibi, Biz de aynı sorunla karşı karşıyayız.

Sorun yalnızca uygulamamın bir sürüm derlemesini yüklediğimde oluyor. Hata ayıklama derlemesini yüklersem düzgün çalışır:
buildTypes {
        release {
            signingConfig signingConfigs.debug
            shrinkResources false
            minifyEnabled false
        }
    }
Android/app/build.gradle konumunda küçültme kaynakları ve minifyEnabled devre dışı bırakılarak sürüm derlemesinde bu sorun düzeltildi

Ama ProGuard'ı devre dışı bıraktığı için garip. Peki ya android apk dosya kaynağı menkul kıymetleri.

Bu yüzden ProGuard etkinleştirmesi ile çalışması için aynısı için proaktif bir çözüme ihtiyacı vardır.

Bu konuya verdiğiniz yanıt için çok teşekkür ederim Teşekkürler!

👍 worked, thanks 👍👍👍👍👍👍

Nov 17 '21 04:11 aygunbi

are there any updates on this issue? disable shrinking solves it but is unconvenient

Add the ProGuard rules (creating the file if you don't have one already). Minimum these rules:
-keep class com.pauldemarco.flutter_blue.** { *; }
-keepclassmembernames class com.pauldemarco.flutter_blue.* { *; }
This is not a Flutter Blue specific problem. For more rules see this blog post: https://csaba.page/blog/flutter-android-crash-remedies.html

Feb 04 '22 01:02 supriyavani

hi there i tried all the above added proguard,disabled shrinkResources false minifyEnabled false and advices from others too still the issue exists my bluetooth app workd fine on the emulator but doesnt work on real device

Feb 04 '22 01:02 supriyavani

somebody pleaseeeeeeeeeeeeeeee help me save my life i am stuck here

Feb 04 '22 01:02 supriyavani

@supriyavani this plugin is dead. Further work is done on flutter_blue_plus.

Feb 04 '22 03:02 boskokg

@boskokg I am getting the same problem with flutter_blue_plus

Mar 01 '22 05:03 afranmuzammil

are there any updates on this issue? disable shrinking solves it but is unconvenient

Add the ProGuard rules (creating the file if you don't have one already). Minimum these rules:
-keep class com.pauldemarco.flutter_blue.** { *; }
-keepclassmembernames class com.pauldemarco.flutter_blue.* { *; }
This is not a Flutter Blue specific problem. For more rules see this blog post: https://csaba.page/blog/flutter-android-crash-remedies.html

It Worked Bro. Thank you

Aug 27 '22 04:08 MuksithMRA

Same issue on october 2022: Unhandled Exception: PlatformException(device_state_error, Field remoteId_ for k.n not found... What worked for me was adding shrinkResources false and minifyEnabled false on android/app/build.gradle.

buildTypes {
        release {
            signingConfig signingConfigs.debug
            shrinkResources false
            minifyEnabled false
        }
    }

I am using flutter_blue: ^0.8.0 flutter build apk --no-shrink did not work, neither did modifying proguard files.

Oct 08 '22 19:10 parzibyte

I have the same issue on flutter_blue_plus. I can do startScan(), but get no device. Although, my device own bluetooth can scan and find devices nearby. I experience it in debug mode.

Dec 16 '23 13:12 lazarekh

flutter_blue flutter_blue copied to clipboard

I/flutter (13169): Error starting scan.

flutter_blue
flutter_blue copied to clipboard