Flutter - 实现多图选择，相机拍照功能

##### demo 地址: https://github.com/iotjin/jh_flutter_demo

使用版本

  photo: ^0.4.8       #相册多图选择  
  image_picker: ^0.6.3+1  #相机拍照，单图选择

包地址

photo packages地址

image_picker packages地址

效果图

主界面 代码

import 'package:flutter/material.dart';
import 'jhPhotoPickerTool.dart';

class PhotoSelectTest extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
        return
          Scaffold(
            appBar:AppBar(
                title:Text('PhotoSelectTest')
            ),
            body:

              Container(
              padding: EdgeInsets.fromLTRB(80, 10, 30, 10),
              color: Colors.red,
              child:
              JhPhotoPickerTool(
                lfPaddingSpace: 110,
                callBack: (var img){
                  print("img-------------");
                  print(img.length);
                  print(img);
                  print("img-------------");

                },
              )
              )

          );

  }
}

jhPhotoPickerTool 代码

import 'package:flutter/material.dart';
import 'jhBottomSheet.dart';
import 'jhImageTool.dart';
import 'package:photo/photo.dart';
import 'package:photo_manager/photo_manager.dart';
import 'dart:io';
import 'package:image_picker/image_picker.dart';

const double itemSpace = 10.0;
const double space = 5.0; //上下左右间距
const double deleBtnWH = 20.0;
const Color bgColor = Colors.yellow;

typedef CallBack = void Function(List imgData);

class JhPhotoPickerTool extends StatefulWidget {

    final double lfPaddingSpace; //外部设置的左右间距
    final CallBack callBack;

    JhPhotoPickerTool({
      this.lfPaddingSpace,
      this.callBack,
    });

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

class _JhPhotoPickerToolState extends State {

      List imgData = List();  //图片list
      List imgPicked = [];

    @override
    void initState() {
      // TODO: implement initState
      super.initState();
      imgData.add("selectPhoto_add"); //先添加 加号按钮 的图片
    }

    @override
  void setState(fn) {
    // TODO: implement setState
    super.setState(fn);
    List data = List();
    data.addAll(imgData);
    data.removeAt(imgData.length-1);
    widget.callBack(data);
  }

  @override
  Widget build(BuildContext context) {

    var kScreenWidth = MediaQuery.of(context).size.width;

    var lfPadding  = widget.lfPaddingSpace==null ?0.0: widget.lfPaddingSpace;
    var ninePictureW =(kScreenWidth-space*2-2*itemSpace-lfPadding);
    var itemWH = ninePictureW/3;
    int columnCount = imgData.length >6 ? 3:imgData.length <= 3 ? 1:2;

    return Container(
        color: bgColor,
        width: kScreenWidth-lfPadding,
        height: columnCount *itemWH +space*2+(columnCount -1)*itemSpace,
        child:
        GridView.builder(
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(//可以直接指定每行（列）显示多少个Item
              //一行的Widget数量
              crossAxisCount:3,
              crossAxisSpacing: itemSpace, //水平间距
              mainAxisSpacing: itemSpace, //垂直间距
              childAspectRatio: 1.0,//子Widget宽高比例
            ),
            physics:NeverScrollableScrollPhysics(),
            padding: EdgeInsets.all(space),//GridView内边距
            itemCount: imgData.length ,
            itemBuilder: (context, index) {

              if(index == imgData.length-1){
                return addBtn(context,setState,imgData,imgPicked);
              }else{
                return
                imgItem(index,setState,imgData,imgPicked);
              }

            }
        )

    );
  }
}


/** 添加按钮 */
Widget addBtn(context,setState,imgData,imgPicked){
  return GestureDetector(
    child: Image(image: JhImageTool.getAssetImage("selectPhoto_add")),
    onTap: (){


      //点击添加按钮
        JhBottomSheet.showText(context, dataArr: ["拍照","相册"],title: "请选择",
        clickCallback: (index,str) async{
          if(index==0){

            var image = await ImagePicker.pickImage(source: ImageSource.camera);
             print(image);
            imgData.insert(imgData.length-1, image.absolute.path);
//            imgPicked.add(image);
            setState(() {
            });

          }
          if(index==1){
            pickAsset(context,setState,imgData,imgPicked);
          }

        }
        );


    },
  );
}



/** 图片和删除按钮 */
Widget imgItem (index,setState,imgData,imgPicked){
  return
    GestureDetector(
      child: Container(
        color: Colors.transparent,
        child: Stack(
            alignment: Alignment.topRight,
            children: [
              ConstrainedBox(
//                child:Image.file(imgData[index], fit: BoxFit.cover),
                child:Image.file(File(imgData[index]), fit: BoxFit.cover),
                constraints: BoxConstraints.expand(),
              ),
              GestureDetector(
                child: Image(image: JhImageTool.getAssetImage("selectPhoto_close"),width: deleBtnWH,height: deleBtnWH,),
                onTap: (){
                  //点击删除按钮
                  setState(() {
                    imgData.removeAt(index);
//                    imgPicked.removeAt(index);
                  });
                },
              )
            ]
        ),
      ),
    onTap: (){
        print("点击第${index}张图片");
    },
    );

}


/** 多图选择 */
void pickAsset(context,setState,imgData,imgPicked) async {

  final result = await PhotoPicker.pickAsset(
    context: context,
//    pickedAssetList: imgPicked,
    maxSelected: 10 -imgData.length,
    pickType:PickType.onlyImage
  );

  if (result != null && result.isNotEmpty) {
    for (var e in result) {
      var file = await e.file;
//      print(file.absolute.path)
      if (!imgData.contains(file.absolute.path)) {
          imgData.insert(imgData.length-1, file.absolute.path);
        }

//      imgData.insert(imgData.length-1, file);
//      if (!imgData.contains(file)) {
//        imgData.insert(imgData.length-1, file);
//      }

    }

  }
  setState(() {});

}