近几年前端开发真是越来越火，H5页面开发的移动端页面甚至有夺我原生开发半壁江山的意思，忧伤忧伤。不过从实际情况考虑，H5一套代码到处跑的特性，我们的Android， IOS ...也就只能呵呵了。然而我还是比较喜欢原生应用，对网络质量要求低，经过H5页面加载不出来一片空白就不受得抓狂！吐槽归吐槽，正事不能落下。
上一篇意图调相机的2方式种以及那些你知道的不状语从句：知道的坑中完成了对意向调起系统相机，结果处理以及一些问题的应对。其实上篇文章还是因为今天的主题web视图中调用相机系统-而起，因为涉及到调用相机本身的一些问题之前不是很明确，所以专门搞了一下，记录下来，所以如果调用相机操作本身有什么疑问或问题，请点击跳转到上一篇电子邮件寻找答案，本篇不再重复。接下来们看看在WebView中调用相机的一些问题。
问题说明
最近有个需求是要上传身份证正反照，说来简单，可偏偏这部分业务是H5页面处理的，所以只能通过H5页面去拍照或选取本地图片了，然而问题来了 - 这段H5代码在用浏览器打开可以实现功能，但是放在WebView中却没有动作。
<!DOCTYPE html><html><head> ???<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> ???<title>相机调用</title> ???<script type="text/javascript"> ???????function previewPhoto(sourceId, targetId) { ???????????var url; ???????????if (navigator.userAgent.indexOf("MSIE") >= 1) { // IE ???????????????url = document.getElementById(sourceId).value; ???????????} else if(navigator.userAgent.indexOf("Firefox") > 0) { // Firefox ???????????????url = window.URL.createObjectURL(document.getElementById(sourceId).files.item(0)); ???????????} else if(navigator.userAgent.indexOf("Chrome") > 0) { // Chrome ???????????????url = window.URL.createObjectURL(document.getElementById(sourceId).files.item(0)); ???????????} ?else if(navigator.userAgent.indexOf("Opera") > 0 ???????????????|| navigator.userAgent.indexOf("Oupeng") > 0) { // Oupeng ???????????????url = window.URL.createObjectURL(document.getElementById(sourceId).files.item(0)); ???????????} else { ???????????????url = "flower_err.jpg"; ???????????} ???????????<!--window.alert("address:" + url);--> ???????????window.alert("address:" + navigator.userAgent); ???????????var imgPre = document.getElementById(targetId); ???????????imgPre.src = url; ???????} ???</script></head><body> ???<a href="http://www.baidu.com">去百度</a> ???<br><br> ???<img id="img" width="200px" height="300px" alt="图片预览区"> ???<br> ???<input type="file" id="pic" name="camera" accept="image/*" onchange="previewPhoto(this.id, ‘img‘);"/> ???<br><br> ???<input type="file" accept="image/*" multiple></body></html>在浏览器中正常运行：
根据前人描述，是因为Android源码中将这部分屏蔽了，需要在webView.setWebChromeClient（new WebChromeClient（））中重写WebChromeClient的openFileChooser（）等方法，接下来我们就打开源码看看。
源码分析
遇到问题看源码是最直接也是最有效的办法，虽然通常情况下阅读源码比看网上一些帖子难度要大点，但却是问题的根本所在。可能有时候遇到很多问题不知道专门从源码下手，这时候就只能用问题去百度，谷歌去了，看看前辈们是怎么解决这个问题的，遇到涉及源码时再回头追本溯源，这样便会对问题本身理解深刻;久而久之，可见成效。说到这里，一个推荐用英语查看各版本源码的地址，毕竟你不会下载了所有版本的源码。闲话少叙，据说不同版本还不一样，那就一个一个看（WebChromeClient.java在\机器人\ WebKit的包下）：
（Android 2.2）8 <= API <= 10（Android 2.3）
以Version 2.3.7_r1（API 10）为例（API <8时就没有这个方法）：
可以看到，openFileChooser（）方法用来告诉客户端打开一个文件选择器，只有一个入参ValueCallback对象uploadMsg，uploadMsg是一个回调值，用来设置待上传文件的Uri，用onReceiveValue（）方法来唤醒等待线程（英语不好，莫见怪）;并且该方法被隐藏了。
（Android 3.0）11 <= API <= 15（Android 4.0.3）
以Version 2.3.7_r1（API 15）为例：
可以看到，该方法也是被隐藏了;不过openFileChooser（）方法比上一版多了一个字符串入参acceptType，H5页面中输入标签声明的文件选择器设置的接受属性值，就是上边H5代码中这一行：
<input type="file" id="pic" name="camera" accept="image/*" onchange="previewPhoto(this.id, ‘img‘);"/>
（Android 4.1.2）16 <= API <= 20（Android 4.4W.2）
以版本4.4W（API 20）为例：
/** * Tell the client to open a file chooser. * @param uploadFile A ValueCallback to set the URI of the file to upload. * ?????onReceiveValue must be called to wake up the thread.a * @param acceptType The value of the ‘accept‘ attribute of the input tag * ????????associated with this file picker. * @param capture The value of the ‘capture‘ attribute of the input tag * ????????associated with this file picker. * @hide */public void openFileChooser(ValueCallback<Uri> uploadFile, String acceptType, String capture) { ???uploadFile.onReceiveValue(null);}
同样有@hide标签;又比上一版多了一个String入参捕获，同样是输入标签的同名属性值（用来指定设备比如capture =“camera”，不过好像用的很少了）。
API> = 21（Android 5.0.1）
以版本5.0（API 21）为例：
/** * Tell the client to open a file chooser. * @param uploadFile A ValueCallback to set the URI of the file to upload. * ?????onReceiveValue must be called to wake up the thread.a * @param acceptType The value of the ‘accept‘ attribute of the input tag * ????????associated with this file picker. * @param capture The value of the ‘capture‘ attribute of the input tag * ????????associated with this file picker. * * @deprecated Use {@link #showFileChooser} instead. * @hide This method was not published in any SDK version. */@Deprecatedpublic void openFileChooser(ValueCallback<Uri> uploadFile, String acceptType, String capture) { ???uploadFile.onReceiveValue(null);} 之前的@hide干嘛用的，之前不知道，但是这里就有说明了 - 这个方法没有在任何SDK版本发布，也就是说这个方法没有公开，所以不会像别的普通方法那样Override，那要怎么搞？后边说。
还有，这个方法被@deprecated标记了，用新方法showFileChooser（）替换了，那我再找找showFileChooser：
/** * Tell the client to show a file chooser. * * This is called to handle HTML forms with ‘file‘ input type, in response to the * user pressing the "Select File" button. * To cancel the request, call <code>filePathCallback.onReceiveValue(null)</code> and * return true. * * @param webView The WebView instance that is initiating the request. * @param filePathCallback Invoke this callback to supply the list of paths to files to upload, * ????????????????????????or NULL to cancel. Must only be called if the * ????????????????????????<code>showFileChooser</code> implementations returns true. * @param fileChooserParams Describes the mode of file chooser to be opened, and options to be * ?????????????????????????used with it. * @return true if filePathCallback will be invoked, false to use default handling. * * @see FileChooserParams */public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, ???????FileChooserParams fileChooserParams) { ???return false;}
看，这个注释就很用心了.onShowFileChooser（）方法和openFileChooser（）同样的作用，但是有更详细的解释 -
- 这个方法用来处理HTML表单中声明type =“file”的输入标签，响应的时机用户按下“选择文件”按钮
- 如果要取消该操作（选择文件操作），需要调用filePathCallback.onReceiveValue（空）; 返回true;
- 返回值的含义：返回true表示认可再该方法中重写的对filePathCallback的操作，返回false表示使用默认处理（即空方法，不做任何处理）
参数filePathCallback泛型由原来的一个Uri变为Uri []，说明可以支持一次选取多个文件（当然，调用系统相机直接拍照的话还是只能一张一拍，此时Uri []中之只有1个人素，若从相册或文件系统选，应该可以多选（本人没有现现，不敢说肯定可以））;
参数FileChooserParams fileChooserParams应该和原来的是一个道理，就是输入标签的属性集合，可以看一下源码：
/** * Parameters used in the {@link #onShowFileChooser} method. */public static abstract class FileChooserParams { ???/** Open single file. Requires that the file exists before allowing the user to pick it. */ ???public static final int MODE_OPEN = 0; ???/** Like Open but allows multiple files to be selected. */ ???public static final int MODE_OPEN_MULTIPLE = 1; ???/** Like Open but allows a folder to be selected. The implementation should enumerate ???????all files selected by this operation. ???????This feature is not supported at the moment. ???????@hide */ ???public static final int MODE_OPEN_FOLDER = 2; ???/** ?Allows picking a nonexistent file and saving it. */ ???public static final int MODE_SAVE = 3; ???/** ????* Parse the result returned by the file picker activity. This method should be used with ????* {@link #createIntent}. Refer to {@link #createIntent} for how to use it. ????* ????* @param resultCode the integer result code returned by the file picker activity. ????* @param data the intent returned by the file picker activity. ????* @return the Uris of selected file(s) or null if the resultCode indicates ????* ????????activity canceled or any other error. ????*/ ???public static Uri[] parseResult(int resultCode, Intent data) { ???????return WebViewFactory.getProvider().getStatics().parseFileChooserResult(resultCode, data); ???} ???/** ????* Returns file chooser mode. ????*/ ???public abstract int getMode(); ???/** ????* Returns an array of acceptable MIME types. The returned MIME type ????* could be partial such as audio/*. The array will be empty if no ????* acceptable types are specified. ????*/ ???public abstract String[] getAcceptTypes(); ???/** ????* Returns preference for a live media captured value (e.g. Camera, Microphone). ????* True indicates capture is enabled, false disabled. ????* ????* Use <code>getAcceptTypes</code> to determine suitable capture devices. ????*/ ???public abstract boolean isCaptureEnabled(); ???/** ????* Returns the title to use for this file selector, or null. If null a default ????* title should be used. ????*/ ???public abstract CharSequence getTitle(); ???/** ????* The file name of a default selection if specified, or null. ????*/ ???public abstract String getFilenameHint(); ???/** ????* Creates an intent that would start a file picker for file selection. ????* The Intent supports choosing files from simple file sources available ????* on the device. Some advanced sources (for example, live media capture) ????* may not be supported and applications wishing to support these sources ????* or more advanced file operations should build their own Intent. ????* ????* <pre> ????* How to use: ????* 1. Build an intent using {@link #createIntent} ????* 2. Fire the intent using {@link android.app.Activity#startActivityForResult}. ????* 3. Check for ActivityNotFoundException and take a user friendly action if thrown. ????* 4. Listen the result using {@link android.app.Activity#onActivityResult} ????* 5. Parse the result using {@link #parseResult} only if media capture was not requested. ????* 6. Send the result using filePathCallback of {@link WebChromeClient#onShowFileChooser} ????* </pre> ????* ????* @return an Intent that supports basic file chooser sources. ????*/ ???public abstract Intent createIntent();}
都有注释，不解释。
解决办法
看完源码一切都明了了，怎么做，重写上边这些方法就好。但是@hide方法不能Override怎么办 - 简单粗暴，直接写（没有代码提示是不是有点心虚？等运行完了就不心有）。为了兼容所有版本，最好把3个参数不同的openFileChooser（）方法都写上，onShowFileChooser（）正常Override就好：
webView.setWebChromeClient(new WebChromeClient() { ???/** ????* 8(Android 2.2) <= API <= 10(Android 2.3)回调此方法 ????*/ ???public void openFileChooser(ValueCallback<Uri> uploadMsg) { ???????Log.e("WangJ", "运行方法 openFileChooser-1"); ???????// (2)该方法回调时说明版本API < 21，此时将结果赋值给 mUploadCallbackBelow，使之 != null ???????mUploadCallbackBelow = uploadMsg; ???????takePhoto(); ???} ???/** ????* 11(Android 3.0) <= API <= 15(Android 4.0.3)回调此方法 ????*/ ???public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) { ???????Log.e("WangJ", "运行方法 openFileChooser-2 (acceptType: " + acceptType + ")"); ???????openFileChooser(uploadMsg); ???} ???/** ????* 16(Android 4.1.2) <= API <= 20(Android 4.4W.2)回调此方法 ????*/ ???public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) { ???????Log.e("WangJ", "运行方法 openFileChooser-3 (acceptType: " + acceptType + "; capture: " + capture + ")"); ???????openFileChooser(uploadMsg); ???} ???/** ????* API >= 21(Android 5.0.1)回调此方法 ????*/ ???@Override ???public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) { ???????Log.e("WangJ", "运行方法 onShowFileChooser"); ???????// (1)该方法回调时说明版本API >= 21，此时将结果赋值给 mUploadCallbackAboveL，使之 != null ???????mUploadCallbackAboveL = filePathCallback; ???????takePhoto(); ???????return true; ???}});/* 省略其他内容 *//** * 调用相机 */private void takePhoto() { ???// 指定拍照存储位置的方式调起相机 ???String filePath = Environment.getExternalStorageDirectory() + File.separator ???????????+ Environment.DIRECTORY_PICTURES + File.separator; ???String fileName = "IMG_" + DateFormat.format("yyyyMMdd_hhmmss", Calendar.getInstance(Locale.CHINA)) + ".jpg"; ???imageUri = Uri.fromFile(new File(filePath + fileName)); ???Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); ???intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); ???startActivityForResult(intent, REQUEST_CODE); ???// 选择图片（不包括相机拍照）,则不用成功后发刷新图库的广播// ???????Intent i = new Intent(Intent.ACTION_GET_CONTENT);// ???????i.addCategory(Intent.CATEGORY_OPENABLE);// ???????i.setType("image/*");// ???????startActivityForResult(Intent.createChooser(i, "Image Chooser"), REQUEST_CODE);}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) { ???super.onActivityResult(requestCode, resultCode, data); ???if (requestCode == REQUEST_CODE) { ???????// 经过上边(1)、(2)两个赋值操作，此处即可根据其值是否为空来决定采用哪种处理方法 ???????if (mUploadCallbackBelow != null) { ???????????chooseBelow(resultCode, data); ???????} else if (mUploadCallbackAboveL != null) { ???????????chooseAbove(resultCode, data); ???????} else { ???????????Toast.makeText(this, "发生错误", Toast.LENGTH_SHORT).show(); ???????} ???}}/** * Android API < 21(Android 5.0)版本的回调处理 * @param resultCode 选取文件或拍照的返回码 * @param data 选取文件或拍照的返回结果 */private void chooseBelow(int resultCode, Intent data) { ???Log.e("WangJ", "返回调用方法--chooseBelow"); ???if (RESULT_OK == resultCode) { ???????updatePhotos(); ???????if (data != null) { ???????????// 这里是针对文件路径处理 ???????????Uri uri = data.getData(); ???????????if (uri != null) { ???????????????Log.e("WangJ", "系统返回URI：" + uri.toString()); ???????????????mUploadCallbackBelow.onReceiveValue(uri); ???????????} else { ???????????????mUploadCallbackBelow.onReceiveValue(null); ???????????} ???????} else { ???????????// 以指定图像存储路径的方式调起相机，成功后返回data为空 ???????????Log.e("WangJ", "自定义结果：" + imageUri.toString()); ???????????mUploadCallbackBelow.onReceiveValue(imageUri); ???????} ???} else { ???????mUploadCallbackBelow.onReceiveValue(null); ???} ???mUploadCallbackBelow = null;}/** * Android API >= 21(Android 5.0) 版本的回调处理 * @param resultCode 选取文件或拍照的返回码 * @param data 选取文件或拍照的返回结果 */private void chooseAbove(int resultCode, Intent data) { ???Log.e("WangJ", "返回调用方法--chooseAbove"); ???if (RESULT_OK == resultCode) { ???????updatePhotos(); ???????if (data != null) { ???????????// 这里是针对从文件中选图片的处理 ???????????Uri[] results; ???????????Uri uriData = data.getData(); ???????????if (uriData != null) { ???????????????results = new Uri[]{uriData}; ???????????????for (Uri uri : results) { ???????????????????Log.e("WangJ", "系统返回URI：" + uri.toString()); ???????????????} ???????????????mUploadCallbackAboveL.onReceiveValue(results); ???????????} else { ???????????????mUploadCallbackAboveL.onReceiveValue(null); ???????????} ???????} else { ???????????Log.e("WangJ", "自定义结果：" + imageUri.toString()); ???????????mUploadCallbackAboveL.onReceiveValue(new Uri[]{imageUri}); ???????} ???} else { ???????mUploadCallbackAboveL.onReceiveValue(null); ???} ???mUploadCallbackAboveL = null;}private void updatePhotos() { ???// 该广播即使多发（即选取照片成功时也发送）也没有关系，只是唤醒系统刷新媒体文件 ???Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE); ???intent.setData(imageUri); ???sendBroadcast(intent);} 为什么要分开chooseBelow（），chooseAbove（）处理？
因为openFileChooser（），onShowFileChooser（）方法参数中那个回调参数的泛型不同（一个开放的，一个开放的[]），分开处理明了一些。
看结果：
怎么样？看完这个结果，粗暴写那几个@hide的方法不心虚了吧？
为什么同样的HTML文件在浏览器中打开和我们做的不一样，浏览器节能拍照又能选文件呢？
那是因为我们写死了要么是使用拍照，要么是用文件选取，如果你愿意，可以根据openFileChooser（），onShowFileChooser（）方法中的参数指定更个性化的响应，也可以做到像浏览器一样。
可能的问题
权限问题
再次提示，了别忘权限问题，别再这里被坑。
打包完成后不能工作
本来在demo中跑的好好的，但当我们打好释放包测试的时候却又发现没拍拍，没法选择图片了!!!真是坑了个爹啊!!!想想不奇怪，因为openFileChooser （）方法被系统隐藏，又不能Override，而我们的release包是开启了混淆的，所以在打包的时候混淆了openFileChooser（），这就导致无法回调openFileChooser（）了。-
keepclassmembers class * extends android。 webkit.WebChromeClient {
public void openFileChooser（...）;
}
当然作为良好的面向对象开发者，你可以用一个借口把这个过程写的更优美一点，我只求能把问题说明白，这里就不实现这一步了。
好像没什么了吧，想起了再加。水平有限，如有错，欢迎指正
照旧，Demo源码GitHub传送门，如有收获，欢迎Star
http://blog.csdn.net/a_running_wolf/article/details/77983739
WebView中打开相机，文件选择器的问题和解决方法
原文地址：https://www.cnblogs.com/huihuizhang/p/8269958.html