lutter 调用原生硬件 Api 实现扫码

 

一、Flutter 扫描二维码条形码插件 barcode_scan

1. 安装

// 请按照官方文档或相关教程进行安装

2. 配置权限

// 在你的 AndroidManifest.xml 中添加摄像头权限
Add the camera permission to your AndroidManifest.xml

// 在你的 AndroidManifest.xml 中添加 BarcodeScanner 活动。请不要修改它的名称。
Add the BarcodeScanner activity to your AndroidManifest.xml. Do NOT modify the name.

3. 检查并配置 build.gradle

dependencies: barcode_scan: ^1.0.0
<activity android:name="com.apptreesoftware.barcodescan.BarcodeScannerActivity"/>

3.1 编辑位于 android 目录下的 build.gradle

// 注意:官方文档配置的 kotlin_version 的版本是1.2.31，但实际上1.2.31会报错。所以本项目使用1.3.0。
buildscript {
    ext.kotlin_version = '1.3.0' ...
    dependencies {
        ...
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

3.2 编辑位于 android/app 目录下的 build.gradle

apply plugin: 'kotlin-android' ...
dependencies {
    ...
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
}

4. 使用插件

import 'package:flutter/material.dart';
import 'package:barcode_scan/barcode_scan.dart';
import 'package:flutter/services.dart';

class ScanPage extends StatefulWidget {
    ScanPage({Key key}) : super(key: key);
    _ScanPageState createState() => _ScanPageState();
}

class _ScanPageState extends State<ScanPage> {
    var barcode;

    Future _scan() async {
        try {
            String barcode = await BarcodeScanner.scan();
            setState(() {
                return this.barcode = barcode;
            });
        } on PlatformException catch (e) {
            if (e.code == BarcodeScanner.CameraAccessDenied) {
                setState(() {
                    return this.barcode = 'The user did not grant the camera permission!';
                });
            } else {
                setState(() {
                    return 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');
        }
    }

    @override
    Widget build(BuildContext context) {
        return Scaffold(
            floatingActionButton: FloatingActionButton(
                child: Icon(Icons.camera_roll),
                onPressed: _scan,
            ),
            appBar: AppBar(
                title: Text("扫码"),
            ),
            body: Text("扫码--${barcode}"),
        );
    }
}

二、Flutter 使用 barcode_scan 提示的错误解决方案

// 错误描述：
Android dependency ‘androidx.core:core’ has different version for the compile (1.0.0) and runtime (1.0.2) classpath. You should manually set the same version via DependencyResolution
    
解决办法
1.android/gradle/wrapper/gradle-wrapper.properties里面
distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.2-all.zip

2.android/build.gradle
dependencies { classpath 'com.android.tools.build:gradle:3.3.0' }

3.android/gradle.properties
加入
android.enableJetifier=true
android.useAndroidX=true

4.android/app/build.gradle 修改版本号：
 make sure compileSdkVersion and targetSdkVersion are at least 28.
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

5.android/app/build.gradle /defaultConfig加上
multiDexEnabled true