Lost connection to device in Flutter? - flutter

Question

I'm facing a problem while using the plugins image_picker: "0.6.1+11" and
barcode_scan: "^1.0.0". Firstly I scan a barcode and then take a picture from the camera.
The problem is most of the times the android app restarts itself after taking image from the camera without any log. The log just prints "Lost connection to the device."
Here is the code:
Future scanCarton() async {
try {
String barcode = await BarcodeScanner.scan();
await getImage().then((imageFile){
if (imageFile != null){
Map<String,String>requestData = new Map<String,String>();
requestData["content"] = barcode;
requestData["type"] = "carton";
requestData["mode"] = "job";
if (widget.orderData.product_type.toLowerCase() == "batched"){
requestData["carton_id"] = "0";
}else{
requestData["carton_id"] = "${scannedCartonCount + 1}";
}
if(this.mounted){
setState(() {
_isLoading = true;
});
}else{
print("Gotcha 2");
}
upload(imageFile, UrlFile.UPLOAD_SCAN_IMAGE, "carton", requestData).then((value){
if(this.mounted){
setState(() {
_isLoading = false;
});
}else{
print("Gotcha 4");
}
incrementCartonCount();
if(widget.orderData.product_type.toLowerCase() == "batched"){
openNextCartonPopup();
}
});
}
});
} on PlatformException catch (e) {
if (e.code == BarcodeScanner.CameraAccessDenied) {
print('The user did not grant the camera permission!');
} else {
print('Unknown error $e') ;
}
} on FormatException{
print( 'null (User returned using the "back"-button before scanning anything. Result)');
} catch (e) {
print('Unknown error: $e');
}
}

Answer 1

You just need to configure to ask for permission beforehand.
For iOS, add the following keys to your Info.plist file, located at <project root>/ios/Runner/Info.plist:
NSPhotoLibraryUsageDescription - describes why your app needs permission for the photo library. This is called Privacy - Photo Library Usage Description in the visual editor.
NSCameraUsageDescription - describes why your app needs access to the camera. This is called Privacy - Camera Usage Description in the visual editor.
NSMicrophoneUsageDescription - describes why your app needs access to the microphone, if you intend to record videos. This is called Privacy - Microphone Usage Description in the visual editor.
In the same way, you need to add permissions in Android.

Answer 2

Try your method with dispose()
#override
void dispose() {
[your method name].dispose();
super.dispose();
}

Answer 3

I got the same issue and found the solution. If you have TextField and imager picker in the same page, please make sure the textfield is unfocused (the cursor should be gone from you TextField) when you pick image.
Do something like FocusScope.of(context).requestFocus(new FocusNode()); in your pickImage method.