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 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 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 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。当然如果需要打开相机拍照，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。

就这样吧。