默认情况下情况下，使用Android的Webview是不能够支持上传文件的。而这个，也是在我们的前端工程师告知之后才了解的。因为 Android的每个版本WebView的实现有差异，因此需要对不同版本去适配。花了一点时间，参考别人的代码，这个问题已经解决，这里把我踩过的坑分享出来。
主要思路是重写WebChromeClient，然后在WebViewActivity中接收选择到的文件Uri，传给页面去上传就可以了。
创建一个WebViewActivity的内部类
public class XHSWebChromeClient extends WebChromeClient {
// For Android 3.0+
public void openFileChooser(ValueCallback<Uri> uploadMsg) {
CLog.i("UPFILE", "in openFile Uri Callback");
if (mUploadMessage != null) {
mUploadMessage.onReceiveValue(null);
}
mUploadMessage = uploadMsg;
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType("*/*");
startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
}
// For Android 3.0+
public void openFileChooser(ValueCallback uploadMsg, String acceptType) {
CLog.i("UPFILE", "in openFile Uri Callback has accept Type" + acceptType);
if (mUploadMessage != null) {
mUploadMessage.onReceiveValue(null);
}
mUploadMessage = uploadMsg;
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
String type = TextUtils.isEmpty(acceptType) "*/*" : acceptType;
i.setType(type);
startActivityForResult(Intent.createChooser(i, "File Chooser"),
FILECHOOSER_RESULTCODE);
}
// For Android 4.1
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
CLog.i("UPFILE", "in openFile Uri Callback has accept Type" + acceptType + "has capture" + capture);
if (mUploadMessage != null) {
mUploadMessage.onReceiveValue(null);
}
mUploadMessage = uploadMsg;
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
String type = TextUtils.isEmpty(acceptType) "*/*" : acceptType;
i.setType(type);
startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
}
//Android 5.0+
@Override
@SuppressLint("NewApi")
public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {
if (mUploadMessage != null) {
mUploadMessage.onReceiveValue(null);
}
CLog.i("UPFILE", "file chooser params：" + fileChooserParams.toString());
mUploadMessage = filePathCallback;
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
if (fileChooserParams != null && fileChooserParams.getAcceptTypes() != null
&& fileChooserParams.getAcceptTypes().length > 0) {
i.setType(fileChooserParams.getAcceptTypes()[0]);
} else {
i.setType("*/*");
}
startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
return true;
}
}
上面openFileChooser是系统未暴露的接口，因此不需要加Override的注解，同时不同版本有不同的参数，其中的参数，第一个 ValueCallback用于我们在选择完文件后，接收文件回调到网页内处理，acceptType为接受的文件mime type。在Android 5.0之后，系统提供了onShowFileChooser来让我们实现选择文件的方法，仍然有ValueCallback，在 FileChooserParams参数中，同样包括acceptType。我们可以根据acceptType，来打开系统的或者我们自己创建文件选择器。当然假如需要打开相机拍照，也可以自己去使用打开相机拍照的Intent去打开即可。
处理选择的文件
以上是打开响应的选择文件的界面，我们还需要处理接收到文件之后，传给网页来响应。因为我们前面是使用startActivityForResult来打开的选择页面，我们会在onActivityResult中接收到选择的结果。Show code：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == FILECHOOSER_RESULTCODE) {
if (null == mUploadMessage) return;
Uri result = data == null || resultCode != RESULT_OK null : data.getData();
if (result == null) {
mUploadMessage.onReceiveValue(null);
mUploadMessage = null;
return;
}
CLog.i("UPFILE", "onActivityResult" + result.toString());
String path = FileUtils.getPath(this, result);
if (TextUtils.isEmpty(path)) {
mUploadMessage.onReceiveValue(null);
mUploadMessage = null;
return;
}
Uri uri = Uri.fromFile(new File(path));
CLog.i("UPFILE", "onActivityResult after parser uri:" + uri.toString());
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
mUploadMessage.onReceiveValue(new Uri[]{uri});
} else {
mUploadMessage.onReceiveValue(uri);
}
mUploadMessage = null;
}
}
以上代码主要就是调用ValueCallback的onReceiveValue方法，将结果传回web。
注意，其他要说的，重要
由于不同版本的差别，Android 5.0以下的版本，ValueCallback 的onReceiveValue接收的参数类型是Uri, 5.0及以上版本接收的是Uri数组，在传值的时候需要注意。
选择文件会使用系统提供的组件或者其他支持的app，返回的uri有的直接是文件的url，有的是contentprovider的uri，因此我们需要统一处理一下，转成文件的uri，可参考以下代码（获取文件的路径）。
调用getPath可以将Uri转成真实文件的Path，然后可以自己生成文件的Uri
public class FileUtils {
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is ExternalStorageProvider.
*/
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is DownloadsProvider.
*/
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is MediaProvider.
*/
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
/**
* Get the value of the data column for this Uri. This is useful for
* MediaStore Uris, and other file-based ContentProviders.
*
* @param context The context.
* @param uri The Uri to query.
* @param selection (Optional) Filter used in the query.
* @param selectionArgs (Optional) Selection arguments used in the query.
* @return The value of the _data column, which is typically a file path.
*/
public static String getDataColumn(Context context, Uri uri, String selection,
String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = {
column
};
try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.moveToFirst()) {
final int column_index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(column_index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
/**
* Get a file path from a Uri. This will get the the path for Storage Access
* Framework Documents, as well as the _data field for the MediaStore and
* other file-based ContentProviders.
*
* @param context The context.
* @param uri The Uri to query.
* @author paulburke
*/
@SuppressLint("NewApi")
public static String getPath(final Context context, final Uri uri) {
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}
// TODO handle non-primary volumes
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id= ";
final String[] selectionArgs = new String[] {
split[1]
};
return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
}
再有，即使获取的结果为null，也要传给web，即直接调用mUploadMessage.onReceiveValue(null),否则网页会阻塞。
最后，在打release包的时候，因为我们会混淆，要特别设置不要混淆WebChromeClient子类里面的openFileChooser方法，由于不是继承的方法，所以默认会被混淆，然后就无法选择文件了。