barcode_scanner_zoom.dart
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import 'dart:async';
import 'package:flutter/material.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:mobile_scanner_example/scanner_button_widgets.dart';
import 'package:mobile_scanner_example/scanner_error_widget.dart';
class BarcodeScannerWithZoom extends StatefulWidget {
const BarcodeScannerWithZoom({super.key});
@override
State<BarcodeScannerWithZoom> createState() => _BarcodeScannerWithZoomState();
}
class _BarcodeScannerWithZoomState extends State<BarcodeScannerWithZoom>
with SingleTickerProviderStateMixin {
BarcodeCapture? barcode;
final MobileScannerController controller = MobileScannerController(
torchEnabled: true,
);
double _zoomFactor = 0.0;
StreamSubscription<Object?>? _barcodesSubscription;
@override
void initState() {
super.initState();
_barcodesSubscription = controller.barcodes.listen((event) {
if (!context.mounted) {
return;
}
setState(() {
barcode = event;
});
});
controller.start();
}
Widget _buildZoomScaleSlider() {
return ValueListenableBuilder(
valueListenable: controller,
builder: (context, state, child) {
if (!state.isInitialized || !state.isRunning) {
return const SizedBox.shrink();
}
final TextStyle labelStyle = Theme.of(context)
.textTheme
.headlineMedium!
.copyWith(color: Colors.white);
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 8.0),
child: Row(
children: [
Text(
'0%',
overflow: TextOverflow.fade,
style: labelStyle,
),
Expanded(
child: Slider(
value: _zoomFactor,
onChanged: (value) {
setState(() {
_zoomFactor = value;
controller.setZoomScale(value);
});
},
),
),
Text(
'100%',
overflow: TextOverflow.fade,
style: labelStyle,
),
],
),
);
},
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('With zoom slider')),
backgroundColor: Colors.black,
body: Stack(
children: [
MobileScanner(
controller: controller,
fit: BoxFit.contain,
errorBuilder: (context, error, child) {
return ScannerErrorWidget(error: error);
},
),
Align(
alignment: Alignment.bottomCenter,
child: Container(
alignment: Alignment.bottomCenter,
height: 100,
color: Colors.black.withOpacity(0.4),
child: Column(
children: [
_buildZoomScaleSlider(),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
ToggleFlashlightButton(controller: controller),
StartStopMobileScannerButton(controller: controller),
Center(
child: SizedBox(
width: MediaQuery.of(context).size.width - 200,
height: 50,
child: FittedBox(
child: Text(
barcode?.barcodes.first.rawValue ??
'Scan something!',
overflow: TextOverflow.fade,
style: Theme.of(context)
.textTheme
.headlineMedium!
.copyWith(color: Colors.white),
),
),
),
),
SwitchCameraButton(controller: controller),
AnalyzeImageFromGalleryButton(controller: controller),
],
),
],
),
),
),
],
),
);
}
@override
Future<void> dispose() async {
_barcodesSubscription?.cancel();
await controller.dispose();
super.dispose();
}
}