PeripheralManager.startAdvertising throws NullPointerException on Android

[ekuleshov]

I've got a NullPointerException reported from some user's devices (Galaxy Tab A 7.0 SM-T280) when PeripheralManager.startAdvertising was called.

According to Android docs the BluetoothAdapter.getBluetoothLeAdvertiser() can return null if Bluetooth is turned off or if Bluetooth LE Advertising is not supported on this device.

It would be nice if unsupported advertising handled more gracefully.

PlatformException: PlatformException(NullPointerException, 
  java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeAdvertiser.startAdvertising(android.bluetooth.le.AdvertiseSettings, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseCallback)' 
  on a null object reference, Cause: null, 
  Stacktrace: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeAdvertiser.startAdvertising(android.bluetooth.le.AdvertiseSettings, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseCallback)' 
    on a null object reference
	at d5.z1.z(MyPeripheralManager.kt:41)
	at d5.z2$a.x(MyAPI.g.kt:52)
	at d5.z2$a.i(MyAPI.g.kt)
	at d5.q2.a(R8$$SyntheticClass)
	at r5.a$b.a(BasicMessageChannel.java:18)
	at f5.c.l(DartMessenger.java:19)
	at f5.c.m(DartMessenger.java:42)
	at f5.c.i(DartMessenger.java)
	at f5.b.run(R8$$SyntheticClass)
	at android.os.Handler.handleCallback(Handler.java:739)
	at android.os.Handler.dispatchMessage(Handler.java:95)
	at android.os.Looper.loop(Looper.java:145)
	at android.app.ActivityThread.main(ActivityThread.java:6939)
	at java.lang.reflect.Method.invoke(Native Method)
	at java.lang.reflect.Method.invoke(Method.java:372)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
, null)
  File "my_api.g.dart", line 1548, in MyPeripheralManagerHostAPI.startAdvertising
  File "<asynchronous suspension>"
  File "my_peripheral_manager.dart", line 176, in MyPeripheralManager.startAdvertising
  File "<asynchronous suspension>"
  ...

[yanshouwang]

Thanks for this report, I didn't notice that PeripheralManager is unsupported on some devices, it's supported on all the devices I have tested. I will add this check in the next version, but I don't have a way to test this.

[ekuleshov]

Thank you. Unfortunately I don't have that device either (running Android 4.1.x). The report came from the crash reporting system. I wonder if the startAdvertising call should return some kind of status to indicate if advertising is supported or not.

[ekuleshov]

It looks like I'm still getting this error with 6.0.2 version. This one came from Xiaomi 22101316G running Android 14.

PlatformException: PlatformException(NullPointerException, java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeAdvertiser.startAdvertising(android.bluetooth.le.AdvertiseSettings, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseCallback)' on a null object reference, Cause: null, Stacktrace: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeAdvertiser.startAdvertising(android.bluetooth.le.AdvertiseSettings, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseData, android.bluetooth.le.AdvertiseCallback)' on a null object reference
	at x2.z1.o(MyPeripheralManager.kt:41)
	at x2.z2$a.x(MyAPI.g.kt:52)
	at x2.z2$a.i(Unknown Source:0)
	at x2.q2.a(Unknown Source:2)
	at l3.a$b.a(BasicMessageChannel.java:18)
	at z2.c.l(DartMessenger.java:19)
	at z2.c.m(DartMessenger.java:42)
	at z2.c.i(Unknown Source:0)
	at z2.b.run(Unknown Source:12)
	at android.os.Handler.handleCallback(Handler.java:958)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loopOnce(Looper.java:222)
	at android.os.Looper.loop(Looper.java:314)
	at android.app.ActivityThread.main(ActivityThread.java:8706)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:565)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
, null)
  File "my_api.g.dart", line 1548, in MyPeripheralManagerHostAPI.startAdvertising
  File "<asynchronous suspension>"
  File "my_peripheral_manager.dart", line 176, in MyPeripheralManager.startAdvertising
  File "<asynchronous suspension>"

[ekuleshov]

And another variant from Amazon tablet running Android 9.

PlatformException: PlatformException(IllegalStateException, java.lang.IllegalStateException, Cause: null, Stacktrace: java.lang.IllegalStateException
	at x2.z1.R(MyPeripheralManager.kt:8)
	at x2.z1.i(MyPeripheralManager.kt:1)
	at x2.z2$a.w(MyAPI.g.kt:6)
	at x2.z2$a.g(Unknown Source:0)
	at x2.p2.a(Unknown Source:2)
	at l3.a$b.a(BasicMessageChannel.java:18)
	at z2.c.l(DartMessenger.java:19)
	at z2.c.m(DartMessenger.java:42)
	at z2.c.i(Unknown Source:0)
	at z2.b.run(Unknown Source:12)
	at android.os.Handler.handleCallback(Handler.java:873)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loop(Looper.java:211)
	at android.app.ActivityThread.main(ActivityThread.java:6775)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
, null)
  File "my_api.g.dart", line 1526, in MyPeripheralManagerHostAPI.removeAllServices
  File "<asynchronous suspension>"
  File "my_peripheral_manager.dart", line 151, in MyPeripheralManager.removeAllServices
  File "<asynchronous suspension>"

[yanshouwang]

Have you checked the bluetooth state before advertising?