Flutter 拍照及相册图片选择功能实现

第三方插件支持

1. camera
   支持自定义相机
2. image_picker
   支持相册图片选择及拍照功能

image_picker

1. 安装
   在pubspec.yaml文件中新增依赖

dependencies:
 ...
 image_picker: ”0.6.0+8“

不确定版本可以写成image_picker: any下载成功后查看pubspec.lock文件获取明确版本号替换pubspec.yaml文件内版本号，及时替换防止依赖版本号不明确造成不必要的报错

2. 设置ios权限
   找到Info.plist文件 项目根目录/ios/Runner/Info.plist
   添加以下keys

• NSPhotoLibraryUsageDescription 调取照片库的权限描述
• NSCameraUsageDescription 访问相机的描述
• NSMicrophoneUsageDescription 访问麦克风的描述

3. 设置android权限

• API 29+ ： 无需配置插件
• API <29
  项目根目录/android/app/src/main/AndroidManifest.xml 和 项目根目录/android/app/src/debug/AndroidManifest.xml 文件中为标签中增加android:requestLegacyExternalStorage="true"属性

4. 使用（旧API） (关键代码截取)

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'dart:io';

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

  @override
  _UploadImageState createState() => _UploadImageState();
}

class _UploadImageState extends State {
  File _image;

  Future getImage() async {
    File image = await ImagePicker.pickImage(source: ImageSource.camera);
    if (image != null) {
      setState(() {
        _image = File(image.path);
      });
    }
  }
  
  Future getLocalImage() async {
    File image = await ImagePicker.pickImage(source: ImageSource.gallery);
    if (image != null) {
      setState(() {
        _image = File(image.path);
      });
    }
  }
  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(children: [
           Expanded(
              child: RaisedButton(
                color: Colors.white,
                elevation: 0.0,
                padding: EdgeInsets.symmetric(vertical: 14.0, horizontal: 0),
                textColor: Color(0xFF1E4C8B),
                onPressed: getImage,
                child: new Text('拍照'),
              ),
            )
          ]),
          Divider(
            color: Color(0xFFE1E6EE),
            height: 1.0,
          ),
          Row(children: [
            Expanded(
              child: RaisedButton(
                color: Colors.white,
                elevation: 0.0,
                padding: EdgeInsets.symmetric(vertical: 14.0, horizontal: 0),
                textColor: Color(0xFF1E4C8B),
                onPressed: getLocalImage,
                child: new Text('从相册选择'),
              ),
            )
         ]),
}

5. 使用（新api 0.6.7）

  final _picker = ImagePicker();
  File _image;

  Future getImage() async {
    PickedFile image = await _picker.getImage(source: ImageSource.camera);
    if (image != null) {
      setState(() {
        _image = File(image.path);
      });
    }
  }
  
  Future getLocalImage() async {
    PickedFile image = await _picker.getImage(source: ImageSource.gallery);
    if (image != null) {
      setState(() {
        _image = File(image.path);
      });
    }
  }