How to fix BLUETTOTH_SCAN permission with Flutter?

Question

I'm on developing a flutter application contains a BLE module with flutter_blue package. I tested it with android versions 8, 10 and 11 and it works but for android 12 I got an exception while scanning devices. the exception is : **E/flutter ( 8367): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: PlatformException(startScan, Need android.permission.BLUETOOTH_SCAN permission for android.content.AttributionSource@bbd118dc: GattService registerScanner, java.lang.SecurityException: Need android.permission.BLUETOOTH_SCAN **

this is the permissions on manifest.xml

  <uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" />
  <uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
  <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.NEARBY_WIFI_DEVICES"
   android:usesPermissionFlags="neverForLocation" />

I would be very thankful if you can help me.

Answer 1

This is how I define permission in android In AndroidManifest.xml

<!-- required for API 18 - 30 -->
<uses-permission
    android:name="android.permission.BLUETOOTH"
    android:maxSdkVersion="30" />
<uses-permission
    android:name="android.permission.BLUETOOTH_ADMIN"
    android:maxSdkVersion="30" />

<!-- required for API 23 - 30 -->
<uses-permission-sdk-23
    android:name="android.permission.ACCESS_COARSE_LOCATION"
    android:maxSdkVersion="30" />
<uses-permission-sdk-23
    android:name="android.permission.ACCESS_FINE_LOCATION"
    android:maxSdkVersion="30" />

<!-- API 31+ -->
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
<uses-permission
    android:name="android.permission.BLUETOOTH_SCAN"
    android:usesPermissionFlags="neverForLocation"
    tools:targetApi="s" />

And You have to ask permission runtime from user based on your needs, you can follow here Android Bluetooth permissions

if (androidApiVersion <= 30) {
  switch (await Permission.location.request()) {

  }
  return;
}

if (30 < androidApiVersion) {
  Map<Permission, PermissionStatus> statuses = await [Permission.bluetoothScan, Permission.bluetoothAdvertise].request();

  if (statuses[Permission.bluetoothScan] == PermissionStatus.granted && statuses[Permission.bluetoothScan] == PermissionStatus.granted) {
   // permission granted
  }
  return;
}

Answer 2

Try adding these permissions.

<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

<uses-permission android:name="android.permission.BLUETOOTH" />

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

For FlutterBlue to function correctly on Android, these permissions are required (especially on newer Android versions).

Ensure that the user is granting location permission.

Use https://pub.dev/packages/permission_handler and request for location permissions like in the snippet below before you start the scan.

await Permission.location.request();