Vant之手机端上传图片只允许拍照上传

1.开发拍照上传页面 - andImgCapture.vue

<template>
  <div>
    <van-button icon="plus" type="primary" :disabled="disabled" @click.stop="clickCamera">拍照上传</van-button>
    <div class="carma-content" v-show="carmaVisible">
      <van-button icon="cross" class="close-photo" type="primary" @click.stop="stopVideoStream"></van-button>
      <video class="carma-video" ref="videoElement" playsinline webkit-playsinline></video>
      <van-button icon="photograph" class="take-photo" @click.stop="capturePhoto"></van-button>
      <canvas ref="canvasElement" style="display: none;"></canvas>
    </div>
    <div class="captured-image-content" v-if="photoVisible">
      <van-button class="cancel-photo" @click="cancelPhoto">取消</van-button>
      <van-button class="confirm-photo" @click="confirmPhoto">完成</van-button>
      <img class="captured-image" v-if="capturedImage" :src="capturedImage" alt="Captured Image">
    </div>
  </div>
</template>
<script setup>
import { onBeforeUnmount, ref, reactive, watch } from 'vue'
import { Toast } from "vant";
const props = defineProps({
  disabled: {
    type: Boolean,
    default: false
  },
  afterRead: {
    type: Function,
    default: () => {
      return true
    }
  },
  beforeRead: {
    type: Function,
    default: () => {}
  }
});
const emit = defineEmits([ 'clickUpload' ])
const carmaVisible = ref(false);
const photoVisible = ref(false);
const capturedImage = ref(null);
const videoElement = ref(null);
const canvasElement = ref(null);
const file = reactive({
  content: '',
  file: {}
});

watch(carmaVisible, newVal => {
  if(newVal){
    document.getElementsByTagName('body')[0].style.backgroundColor = '#000000'
  } else {
    document.getElementsByTagName('body')[0].style.backgroundColor = '#ffffff'
  }
});

onBeforeUnmount(() => {
  stopVideoStream();
});

const clickCamera = async (e) => {
  emit('clickUpload', e);
  // 开启摄像头前检测是否触发了阻止默认事件
  if(e.defaultPrevented){
    return 
  } else {
    setupCamera();
  }
};

const setupCamera = async () => {
  try {
    initFile();
    navigator.mediaDevices.getUserMedia({ 
      video: { facingMode: "environment" },
    }).then(stream => {
      const videoElementObj = videoElement.value;
      videoElementObj.srcObject = stream;
      carmaVisible.value = true;
      if ("srcObject" in videoElementObj) {
        videoElementObj.srcObject = stream;
      } else {
        // 防止在新的浏览器里使用它，因为它已经不再支持了
        videoElementObj.src = window.URL.createObjectURL(stream);
      }
      videoElementObj.onloadedmetadata = function(e) {
        videoElementObj.play();
      };
    }).catch(err => {
      Toast.fail('访问用户媒体设备失败：', err.message);
    });
  } catch (error) {
    carmaVisible.value = false;
    console.log('获取摄像头失败:', error);
    Toast.fail('获取摄像头失败');
  }
}

const capturePhoto = () => {
  const videoElementObj = videoElement.value;
  const canvasElementObj = canvasElement.value;
  const context = canvasElementObj.getContext('2d');

  canvasElementObj.width = videoElementObj.videoWidth;
  canvasElementObj.height = videoElementObj.videoHeight;

  context.drawImage(videoElementObj, 0, 0, canvasElementObj.width, canvasElementObj.height);
  capturedImage.value = canvasElementObj.toDataURL();
  photoVisible.value = true;
}

const cancelPhoto = () => {
  photoVisible.value = false;
  capturedImage.value = '';
}

const confirmPhoto = () => {
  stopVideoStream();
  file.content = capturedImage.value;
  file.file = base64ToFile(capturedImage.value, 'photo'+ Date.now());

  const passBeforeRead = props.beforeRead(file);
  if(passBeforeRead || passBeforeRead === undefined){
    props.afterRead(file);
  }
}

const initFile = () => {
  file.content = '';
  file.file = '';
  capturedImage.value = '';
}

const stopVideoStream = () => {
  photoVisible.value = false;
  carmaVisible.value = false;
  if (videoElement.value && videoElement.value.srcObject) {
    const tracks = videoElement.value.srcObject.getTracks();
    tracks.forEach((track) => {
      track.stop();
    });
  }
}

const base64ToFile = (dataurl, fileName) => {
  let arr = dataurl.split(',');
  let mime = arr[0].match(/:(.*?);/)[1];
  // suffix是该文件的后缀
  let suffix = mime.split('/')[1];
  // atob 对经过 base-64 编码的字符串进行解码
  let bstr = atob(arr[1]);
  // n 是解码后的长度
  let n = bstr.length;
  // Uint8Array 数组类型表示一个 8 位无符号整型数组 初始值都是 数子0
  let u8arr = new Uint8Array(n);
  // charCodeAt() 方法可返回指定位置的字符的 Unicode 编码。这个返回值是 0 - 65535 之间的整数
  while (n--) {
    u8arr[n] = bstr.charCodeAt(n);
  }
  // new File返回File对象 第一个参数是 ArraryBuffer 或 Bolb 或Arrary 第二个参数是文件名
  // 第三个参数是 要放到文件中的内容的 MIME 类型
  return new File([u8arr], `${ fileName }.${ suffix }`, {
    type: mime,
  });
}
</script>
<style lang="less" scoped>
.carma-content{
  width: 100%;
  height: 100vh;
  position: fixed;
  top: 0;
  left: 0;
  background: #000000;
  z-index: 99;
}
.close-photo{
  position: absolute;
  left: 0;
  z-index: 100;
  border: unset;
  background: #000000;
}
.carma-video{
  width: 100vw;
  height: auto;
  position: absolute;
  top: 50%;
  left: 0px;
  transform: translateY(-55%);
}
.take-photo{
  width: 70px;
  height: 70px;
  position: absolute;
  z-index: 100;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  border-radius: 50%;
  font-size: 28px;
  background: #ffffff;
}
.captured-image-content{
  width: 100%;
  height: 100vh;
  display: flex;
  align-items: center;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 9999;
  background: #000000;
}
.cancel-photo{
  color: #ffffff;
  border: unset;
  background: none;
  top: 0;
  left: 0;
  position: fixed;
}
.confirm-photo{
  color: #0570db;
  border: unset;
  background: none;
  top: 0;
  right: 0;
  position: fixed;
}
.captured-image{
  width: 100%;
  height: auto;
}
</style>

2.编写androidOrIos.js

export const checkMobileModel = () => {
  let u = navigator.userAgent;
  let isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1;
  let isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/);

  if (isAndroid) {
    return 'Android'
  }

  if (isIOS) {
    return 'IOS'
  }

   return ''
}

3.导入两个文件

import AndImgCapture from "@/components/andImgCapture/andImgCapture.vue";
import { checkMobileModel } from "@/utils/androidOrIos";

4.在主页面实现拍照上传基本功能

<AndImgCapture
  v-if="checkMobileModel() === 'Android'"
  :after-read="(file) => uploaderAfter(file, 'promotionPhoto')"
  @click-upload="openUpload($event, item)"
>
</AndImgCapture>
<van-uploader
  v-else
  :multiple="true"
  :preview-image="false"
  :max-size="50000 * 1024"
  :after-read="(file) => uploaderAfter(file, 'promotionPhoto')"
  @click-upload="openUpload($event, item)"
  @oversize="onOversize"
  capture="camera"
  accept="image/*"
>
  <van-button icon="plus" type="primary">拍照上传</van-button>
</van-uploader>

即可。