IOS
uses the capture='user' attribute to call the front camera.
capture='camera' calls the rear camera.
Apple mobile phone tests are available for Android but not (Android phones are all rear cameras...)
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<!-- 使页面适配手机屏幕 -->
<meta name="viewport" content="width=device-width,initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"/>
<title></title>
<!-- 引入JQuery的JS文件 -->
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
</head>
<body>
<!-- 这里是通过点击某个Div来隐式创建一个 input 控件，然后实现直接访问相机的功能。-->
<div id="demoForClick">
<div id="btnID">这里是直接获取iOS相机功能</div>
</div>
<!-- 换行 -->
<br/><br/><br/>
<div>
<!-- 直接访问相机功能进行拍照 -->
<label>ios照相机</label>
<input type="file" id='image' accept="image/*" capture='user'>
</div>
<!-- 换行 -->
<br/><br/><br/>
<script>
// 隐式创建一个input控件，然后实现直接访问相册
var inputUploadObj = '';
$("#btnID").on("click", function() {
inputUploadObj = document.createElement('input')
inputUploadObj.setAttribute('id', 'input_upload_ID');
inputUploadObj.setAttribute('type', 'file');
// 添加这个属性，就可以唤起相机的功能
inputUploadObj.setAttribute('capture', 'camera');
// 这里如果不加属性 accept 是 "image/*" 或者 "video/*"，就默认打开摄像头，既可以拍照也可以录像
inputUploadObj.setAttribute('accept', 'image/*');
//inputUploadObj.setAttribute('accept', 'image/*');
inputUploadObj.setAttribute("style", 'visibility:hidden');
// 这里将创建的隐式input控件拼接到body的最后面，会增加页面的长度，所以要在适当的时候，移除掉这个隐式创建的input控件
document.body.appendChild(inputUploadObj);
// 这里是模拟点击了input控件
inputUploadObj.click();
});
</script>
</body>
</html>
Android
Android uses navigator.mediaDevices to call the camera
attribute facingMode: 'user' is the front camera
attribute facingMode: {exact : 'environment'} is the rear camera
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>摄像头拍照</title>
</head>
<body onload='init()'>
<video id="video">
</video>
<div id='operators'>
<button id="capture">拍照</button> <button id="changeCamera">切换摄像头</button>
</div>
<canvas id="canvas" width="480" height="320"></canvas>
<script>
var cameraFront="";
//访问用户媒体设备的兼容方法
function getUserMedia(constraints, success, error) {
currentCamera=constraints;
if (navigator.mediaDevices.getUserMedia) {
//最新的标准API
navigator.mediaDevices.getUserMedia(constraints).then(success).catch(error);
} else if (navigator.webkitGetUserMedia) {
//webkit核心浏览器
navigator.webkitGetUserMedia(constraints,success, error)
} else if (navigator.mozGetUserMedia) {
//firfox浏览器
navigator.mozGetUserMedia(constraints, success, error);
} else if (navigator.getUserMedia) {
//旧版API
navigator.getUserMedia(constraints, success, error);
}
}
let video = document.getElementById('video');
let canvas = document.getElementById('canvas');
let context = canvas.getContext('2d');
//视频流变量
var localMediaStream;
function success(stream) {
//兼容webkit核心浏览器
let CompatibleURL = window.URL || window.webkitURL;
//将视频流设置为video元素的源
console.log(stream);
//video.src = CompatibleURL.createObjectURL(stream);
video.srcObject = stream;
video.play();
localMediaStream=stream;
}
function error(error) {
alert(`访问用户媒体设备失败${
error.name}, ${
error.message}`);
}
if (navigator.mediaDevices.getUserMedia || navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia) {
//调用用户媒体设备, 访问摄像头 video和audio： {video : {width: 480, height: 320}} 使用前置摄像头, 代码如下: {video: {facingMode: 'user'}} 后置摄像头, 代码如下: {video: {facingMode: {exact : 'environment'}}}
getUserMedia({
audio: true,video: {
facingMode: {
exact : 'environment'}}}, success, error);
} else {
alert('不支持访问用户媒体');
}
document.getElementById('capture').addEventListener('click', function () {
context.drawImage(video, 0, 0, 480, 320);
})
//当前摄像头
var currentCamera;
document.getElementById('changeCamera').addEventListener('click', function () {
//关闭打开的摄像头
localMediaStream.getTracks().forEach(function(track) {
track.stop();
});
if(currentCamera.video.facingMode=='user')
{
getUserMedia({
audio: true,video: {
facingMode: {
exact : 'environment'}}}, success, error);
}else{
getUserMedia({
audio: true,video: {
facingMode: 'user'}}, success, error);
}
})
function init(){
document.getElementById('operators').style.width=document.getElementById('video').style.width;
document.getElementById('operators').style.textAlign="center";
}
</script>
</body>
</html>