我的Flutter应用程序使用相机pugin和条形码读取器插件来拍照和扫描产品。当我先打开阅读器，然后拍照时，一切正常。但是，如果我先打开相机，条形码扫描器在识别条形码时会崩溃。我认为问题是相机页面，因为我尝试了多个扫描仪，并且每次都出现相同的错误：
java.lang.IllegalArgumentException: Surface was abandoned
E/AndroidRuntime(26336): at android.hardware.camera2.utils.SurfaceUtils.getSurfaceSize(SurfaceUtils.java:70)
E/AndroidRuntime(26336): at android.hardware.camera2.params.OutputConfiguration.<init>(OutputConfiguration.java:237)
E/AndroidRuntime(26336): at android.hardware.camera2.params.OutputConfiguration.<init>(OutputConfiguration.java:101)
E/AndroidRuntime(26336): at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSession(CameraDeviceImpl.java:499)
E/AndroidRuntime(26336): at io.flutter.plugins.camera.CameraPlugin$Camera.startPreview(CameraPlugin.java:672)
E/AndroidRuntime(26336): at io.flutter.plugins.camera.CameraPlugin$Camera.access$2000(CameraPlugin.java:237)
E/AndroidRuntime(26336): at io.flutter.plugins.camera.CameraPlugin$Camera$3.onOpened(CameraPlugin.java:437)
E/AndroidRuntime(26336): at android.hardware.camera2.impl.CameraDeviceImpl$1.run(CameraDeviceImpl.java:139)
E/AndroidRuntime(26336): at android.os.Handler.handleCallback(Handler.java:789)
E/AndroidRuntime(26336): at android.os.Handler.dispatchMessage(Handler.java:98)
E/AndroidRuntime(26336): at android.os.Looper.loop(Looper.java:164)
E/AndroidRuntime(26336): at android.app.ActivityThread.main(ActivityThread.java:6938)
E/AndroidRuntime(26336): at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(26336): at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
E/AndroidRuntime(26336): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
E/AndroidRuntime(26336): Caused by: android.hardware.camera2.legacy.LegacyExceptionUtils$BufferQueueAbandonedException
E/AndroidRuntime(26336): at android.hardware.camera2.legacy.LegacyExceptionUtils.throwOnError(LegacyExceptionUtils.java:73)
E/AndroidRuntime(26336): at android.hardware.camera2.legacy.LegacyCameraDevice.getSurfaceSize(LegacyCameraDevice.java:583)
E/AndroidRuntime(26336): at android.hardware.camera2.utils.SurfaceUtils.getSurfaceSize(SurfaceUtils.java:68)
打开扫描仪的功能（使用：https://pub.dartlang.org/packages/barcode_scan）：
scan() async{
try {
String barcode = await BarcodeScanner.scan();
setState(() {
_nummer = barcode;
_nummerController.text = _nummer;
});
} on PlatformException catch (e) {
if (e.code == BarcodeScanner.CameraAccessDenied) {
} else {
}
} on FormatException{
} catch (e) {
}
}
该功能将打开我的相机页面：
takePhoto() async {
final result = await Navigator.push(
context, MaterialPageRoute(builder: (context) => new CameraApp()));
setState(() {
_image = result.toString();
});
}
我的camera.dart文件（使用：https://pub.dartlang.org/packages/camera）
import 'dart:async';
import 'dart:io';
import 'package:camera/camera.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
class CameraApp extends StatefulWidget {
@override
_CameraAppState createState() => new _CameraAppState();
}
class _CameraAppState extends State<CameraApp> {
CameraController controller;
List<CameraDescription> cameras;
bool _isReady = false;
final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
Future<void> _setupCameras() async {
try {
// initialize cameras.
cameras = await availableCameras();
// initialize camera controllers.
controller = new CameraController(cameras[0], ResolutionPreset.medium);
await controller.initialize();
} on CameraException catch (_) {
// do something on error.
}
if (!mounted) return;
setState(() {
_isReady = true;
});
}
@override
void initState() {
super.initState();
_setupCameras();
}
@override
void dispose() {
controller?.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
double width = MediaQuery.of(context).size.width;
double height = MediaQuery.of(context).size.height;
if(controller == null){
return new Scaffold(
appBar: new AppBar(
brightness: Brightness.light,
backgroundColor: const Color.fromRGBO(127, 22, 22, 1.0),
leading: new GestureDetector(
child: new Icon(Icons.close),
onTap: () {
Navigator.pop(context);
},
),
title: new Text("Wein hinzufügen"),
),
body: new Center(child:
new Column(
children: <Widget>[
new Container(child: new Text("Es ist ein Fehler aufgetreten!", style: new TextStyle(fontSize: 24.0)), margin: new EdgeInsets.only(top: 40.0, bottom: 10.0),),
new Container(child: new Text("Eventuell keine Kamera Erlaubniss.", style: new TextStyle(fontSize: 14.0),),),
new Container(margin: new EdgeInsets.only(top: 100.0),child: new GestureDetector( onTap: _setupCameras,
child: new Image.asset("assets/images/refresh.png", width: 60.0, height: 60.0,)
),
),
]
))
);
}else{
if (!controller.value.isInitialized) {
return new Scaffold(
appBar: new AppBar(
brightness: Brightness.light,
backgroundColor: const Color.fromRGBO(127, 22, 22, 1.0),
leading: new GestureDetector(
child: new Icon(Icons.close),
onTap: () {
Navigator.pop(context);
},
),
title: new Text("Wein hinzufügen"),
),
body: new Center(child:
new Column(
children: <Widget>[
new Container(child: new Text("Es ist ein Fehler aufgetreten!", style: new TextStyle(fontSize: 24.0)), margin: new EdgeInsets.only(top: 40.0, bottom: 10.0),),
new Container(child: new Text("Eventuell keine Kamera Erlaubniss.", style: new TextStyle(fontSize: 14.0),),),
new Container(margin: new EdgeInsets.only(top: 100.0),child: new GestureDetector( onTap: _setupCameras,
child: new Image.asset("assets/images/refresh.png", width: 60.0, height: 60.0,)
),
),
]
))
);
}else {
return new Scaffold(
key: _scaffoldKey,
resizeToAvoidBottomPadding: false,
appBar: new AppBar(
brightness: Brightness.light,
backgroundColor: const Color.fromRGBO(127, 22, 22, 1.0),
leading: new GestureDetector(
child: new Icon(Icons.close),
onTap: () {
Navigator.pop(context);
},
),
title: new Text("Wein hinzufügen"),
),
body: new Column(children: <Widget>[
new Stack(alignment: Alignment.center, children: <Widget>[
new AspectRatio(
aspectRatio: controller.value.aspectRatio,
child: new CameraPreview(controller)),
new Container(
width: width * 0.6,
height: width * 0.8,
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color.fromRGBO(229, 229, 229, 0.3),
border: new Border.all(
color: const Color.fromRGBO(127, 22, 22, 1.0),
width: 1.0),
),
)
]),
new Expanded(
child: new GestureDetector(
onTap: onTakePictureButtonPressed,
child: new Container(
color: Colors.black,
child: new Center(
child: new Container(
width: 70.0,
height: 70.0,
decoration: new BoxDecoration(
boxShadow: [
new BoxShadow(
color: Colors.black, blurRadius: 20.0)
],
border: new Border.all(
color: const Color.fromRGBO(
92, 13, 13, 1.0),
width: 8.0),
color: const Color.fromRGBO(127, 22, 22, 1.0),
shape: BoxShape.circle),
),
),
)))
]));
}
}
}
String timestamp() => new DateTime.now().millisecondsSinceEpoch.toString();
void onTakePictureButtonPressed() {
takePicture().then((String filePath) {
if (mounted) {
setState(() {
});
if (filePath != null){
showInSnackBar('Picture saved to $filePath');
controller.dispose();
Navigator.pop(context, filePath);
}
}
});
}
Future<String> takePicture() async {
if (!controller.value.isInitialized) {
showInSnackBar("Error, bitte versuchen sie es erneut!");
return null;
}
final Directory extDir = await getApplicationDocumentsDirectory();
final String dirPath = '${extDir.path}/Bilder/Notizen';
await new Directory(dirPath).create(recursive: true);
final String filePath = '$dirPath/${timestamp()}.png';
if (controller.value.isTakingPicture) {
// A capture is already pending, do nothing.
return null;
}
try {
await controller.takePicture(filePath);
} on CameraException catch (e) {
showInSnackBar(e.toString());
return null;
}
return filePath;
}
void showInSnackBar(String message) {
_scaffoldKey.currentState
.showSnackBar(new SnackBar(content: new Text(message)));
}
}
答案 0 :(得分：0)
我的相机拍照功能崩溃了。
<块引用>"java.lang.NullPointerException: Attempt to invoke virtual method 'int io.flutter.embedding.engine.systemchannels.PlatformChannel$DeviceOrientation.ordinal()' 在空对象引用 E/AndroidRuntime(18591) 上： io.flutter.plugins.camera.DeviceOrientationManager.getMediaOrientation(DeviceOrientationManager.java:58)"
对我来说帮助添加 在 initialize() 之后等待 controller.lockCaptureOrientation()。 试试这个，也许对你有帮助
try {
...
await controller.initialize();
await controller.lockCaptureOrientation();
}
答案 1 :(得分：-1)
尝试清理项目并重建：
flutter clean