一、前言

我们开发原生的时候可以使用zxing进行生成条形码与二维码，但是flutter的插件中只找到了二维码的生成与扫描，业务需求里面需要条形码的生成，需要在原有的基础上进行修改。

二、效果图

image

image

三、扫码逻辑

通过MethodChannel调用原生代码，进行效果的实现

const MethodChannel _channel = const MethodChannel('qr_scan')

四、具体实现方案

1.使用的第三方库

qrscan: ^0.2.17

2.主要代码

class MyApp extends StatefulWidget {
  MyApp({Key key}) : super(key: key);

  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String barcode = null;
  Uint8List bytes = Uint8List(0);
  @override
  initState() {

    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text('二维码生成器'),
        ),
        body: Container(
          margin: EdgeInsets.only(top: 50),
          child: Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.start,
              children: <Widget>[
                Container(
                  width: 200,
                  height: 200,
                  child: Image.memory(bytes),
                ),
//              _createBody(),
                Text(barcode ?? "请扫描相关的条形码"),
                MaterialButton(
                  onPressed: scan,
                  child: Text("Scan"),
                  color: Colors.blue,
                  textColor: Colors.white,
                ),
                MaterialButton(
                  onPressed: () => _generateBarCode(barcode),
                  child: Text("生成普通二维码"),
                  color: Colors.blue,
                  textColor: Colors.white,
                ),
                MaterialButton(
                  onPressed: () => _generateBarCode1(barcode),
                  child: Text("生成条形码"),
                  color: Colors.blue,
                  textColor: Colors.white,
                ),
              ],
            ),
          )
        ),
    );
  }

  ///扫描二维码
  Future scan() async {
    try {
      String barcode = await scanner.scan();
      print("这是扫描出来的结果"+barcode);
      setState(() {
        this.barcode = barcode;
        bytes=Uint8List(0);
//        ClipboardData data = new ClipboardData(text:barcode);
//        Clipboard.setData(data);
      });
    } on Exception catch (e) {
      if (e == scanner.CameraAccessDenied) {
        setState(() {
          this.barcode = 'The user did not grant the camera permission!';
        });
      } else {
        setState(() => this.barcode = 'Unknown error: $e');
      }
    } on FormatException {
      setState(() => this.barcode =
          'null (User returned using the "back"-button before scanning anything. Result)');
    } catch (e) {
      setState(() => this.barcode = 'Unknown error: $e');
    }
  }


  Future _generateBarCode(String inputCode) async {
    Uint8List result = await scanner.generateBarCode(inputCode);
    this.setState(() => this.bytes = result);
  }

  Future _generateBarCode1(String inputCode) async {
    Uint8List result = await scanner.generateBarCode1(inputCode);
    this.setState(() => this.bytes = result);
  }
}

五、注意事项

通过以上操作只能实现扫描与生成二维码的操作，条形码的生成还需要以下步骤进行修改。

1.flutter端添加关键代码

image

Future<Uint8List> generateBarCode1(String code) async {
  assert(code != null && code.isNotEmpty);
  return await _channel.invokeMethod('generate_barcode1', {"code": code});
}

2.Android端添加关键代码

image

case "generate_barcode1":
                this.result = result;
                generateQrCode1(call);
                break;

    private void generateQrCode1(MethodCall call) {
        String code = call.argument("code");
        Bitmap bitmap = createImage1(code, 200, 200, null);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        byte[] datas = baos.toByteArray();
        this.result.success(datas);
    }

public static Bitmap createImage1(String text, int w, int h, Bitmap logo) {
        if (TextUtils.isEmpty(text)) {
            return null;
        }
        try {
            //条形码CODE_128
            BarcodeFormat fomt=BarcodeFormat.CODE_128;
            BitMatrix matrix=new MultiFormatWriter().encode(text, fomt, w, h);
            int width=matrix.getWidth();
            int height=matrix.getHeight();
            int[] pixel=new int[width*height];
            for(int i=0;i<height;i++){
                for(int j=0;j<width;j++){
                    if (matrix.get(j, i)) {
                        pixel[i * width + j] = 0xff000000;
                    } else {
                        pixel[i * width + j] = 0xffffffff;
                    }
                }
            }
            Bitmap bmapp=Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
            bmapp.setPixels(pixel, 0, width, 0, 0, width, height);
            return bmapp;
        } catch (WriterException e) {
            e.printStackTrace();
        }
        return null;
    }

3.二维码生成添加logo的方法

Bitmap imageBitmap = BitmapFactory.decodeFile("/sdcard/logo.png");

图片的路径需要保持一致， decodeFile默认的是sd卡

最后附上Demo地址,如有什么不足和错误请指正，觉得受用反手就给颗??吧