我正在尝试编写一个抖动应用程序，在该应用程序中，我打开照相机，向用户询问一个问题：当用户按下按钮应打开闪光灯时，会显示照相机浮动操作按钮，但有例外。那是我使用波动camera软件包和Lamp的代码：
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:lamp/lamp.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:backback/Resultat/testclass.dart' as globals;
import 'package:backback/Camera/camerafrontT.dart';
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'displaybackT.dart';
void main()=> runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Selectable GridView',
theme: ThemeData(
brightness: Brightness.dark,
),
home:CameraScreen(),
);
}
}
class CameraScreen extends StatefulWidget {
@override
_CameraScreenState createState() {
return _CameraScreenState();
}
}
class _CameraScreenState extends State {
bool _hasFlash = false;
bool _isOn = false;
double _intensity = 1.0;
initPlatformState() async {
bool hasFlash = await Lamp.hasLamp;
print("Device has flash ? $hasFlash");
setState(() { _hasFlash = hasFlash; });
}
int a = 5;
CameraController controller;
List cameras;
int selectedCameraIdx;
String imagePath;
Future _turnFlash() async {
_intensityChanged(5.0);
_isOn ? Lamp.turnOff() : Lamp.turnOn(intensity: _intensity); var f = await Lamp.hasLamp;
setState((){
_hasFlash = f;
_isOn = !_isOn;
});
}
_intensityChanged(double intensity) {
Lamp.turnOn(intensity : intensity);
setState((){
_intensity = intensity;
});
}
@override
void initState() {
super.initState();
initPlatformState();
availableCameras().then((availableCameras) {
cameras = availableCameras;
if (cameras.length > 0) {
setState(() {
selectedCameraIdx = 0;
});
_initCameraController(cameras[selectedCameraIdx]).then((void v) {});
} else {
print("No camera available");
}
}).catchError((err) {
print('Error: $err.code\nError Message: $err.message');
});
}
Future _initCameraController(CameraDescription cameraDescription) async {
if (controller != null) {
await controller.dispose();
}
controller = CameraController(cameraDescription, ResolutionPreset.high);
// If the controller is updated then update the UI.
controller.addListener(() {
if (mounted) {
setState(() {});
}
if (controller.value.hasError) {
print('Camera error ${controller.value.errorDescription}');
}
});
try {
await controller.initialize();
} on CameraException catch (e) {
_showCameraException(e);
}
if (mounted) {
setState(() {});
}
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Click To Share'),
backgroundColor: Colors.blueGrey,
),
body: Container(
child: SafeArea(
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
Expanded(
flex: 1,
child: _cameraPreviewWidget(),
),
SizedBox(height: 10.0),
if (a == 5)
Text(
'La vue dans le viseur est-elle degage',
style: TextStyle(fontSize: 20),textAlign: TextAlign.center,
),
if (a == 0) Text('essayer de prendre une photo',textAlign: TextAlign.center,),
Container(
height: 25,
),
if (a == 0)
FloatingActionButton(
child: Icon(Icons.camera_alt),
// Provide an onPressed callback.
onPressed: () {
_turnFlash();
//_onCapturePressed(context);
}),
if (a == 5)
Row(
children: <Widget>[
Container(
width: MediaQuery.of(context).size.width * 0.05,
),
Container(
margin: const EdgeInsets.all(15.0),
padding: const EdgeInsets.all(3.0),
decoration: BoxDecoration(
border: Border.all(
width: 3.0,
color: Colors.lightBlueAccent,
),
borderRadius: BorderRadius.all(Radius.circular(
30.0) // <--- border radius here
),
),
child: InkWell(
child: Text(
'NON',
style: TextStyle(fontSize: 20),
),
onTap:(){
globals.Data.etatcameraback('0');
Navigator.push(
context,
MaterialPageRoute(builder: (context) => CameraScreen2()),
);
},
)),
Container(width: MediaQuery.of(context).size.width * 0.5),
Container(
margin: const EdgeInsets.all(15.0),
padding: const EdgeInsets.all(3.0),
decoration: BoxDecoration(
border: Border.all(
width: 3.0,
color: Colors.lightBlueAccent,
),
borderRadius: BorderRadius.all(Radius.circular(
30.0) // <--- border radius here
),
),
child: InkWell(
child: Text(
'Oui',
style: TextStyle(fontSize: 20),
),
onTap : () {
a = 0;
setState(() {
a =0;
});
},
)),
],
),
SizedBox(height: 20.0)
],
),
),
),
));
}
/// Display Camera preview.
Widget _cameraPreviewWidget() {
if (controller == null || !controller.value.isInitialized) {
return const Text(
'Loading',
style: TextStyle(
color: Colors.white,
fontSize: 20.0,
fontWeight: FontWeight.w900,
),
);
}
return AspectRatio(
aspectRatio: controller.value.aspectRatio,
child: CameraPreview(controller),
);
}
/// Display the control bar with buttons to take pictures
Widget _captureControlRowWidget(context) {
return Expanded(
child: Align(
alignment: Alignment.center,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
mainAxisSize: MainAxisSize.max,
children: [
FloatingActionButton(
child: Icon(Icons.camera),
backgroundColor: Colors.blueGrey,
onPressed: () {
_onCapturePressed(context);
})
],
),
),
);
}
void _onCapturePressed(context) async {
// Take the Picture in a try / catch block. If anything goes wrong,
// catch the error.
try {
// Attempt to take a picture and log where it's been saved
final path = join(
// In this example, store the picture in the temp directory. Find
// the temp directory using the `path_provider` plugin.
(await getTemporaryDirectory()).path,
'${DateTime.now()}.png',
);
print(path);
await controller.takePicture(path);
// If the picture was taken, display it on a new screen
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => PreviewImageScreen(imagePath: path),
),
);
} catch (e) {
// If an error occurs, log the error to the console.
print(e);
}
}
void _showCameraException(CameraException e) {
String errorText = 'Error: ${e.code}\nError Message: ${e.description}';
print(errorText);
print('Error: ${e.code}\n${e.description}');
}
}
该应用程序正常运行。我按下按钮以运行闪光灯，但有一个由闪动引起的异常，但闪光灯没有打开
E/MethodChannel#github.com/clovisnicolas/flutter_lamp( 4197): at android.app.ActivityThread.main(ActivityThread.java:7055)
E/MethodChannel#github.com/clovisnicolas/flutter_lamp( 4197): at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#github.com/clovisnicolas/flutter_lamp( 4197): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:523)
E/MethodChannel#github.com/clovisnicolas/flutter_lamp( 4197): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:836)
E/flutter ( 4197): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception:
PlatformException(error, getParameters failed (empty parameters), null)
我需要一些帮助来解决我的问题。我看上去很长，但是没有发现任何有趣的结果。