Webview 支持文件上传

默认情况下情况下，在一个带有input tpye=file标签的Html页面，使用Android的WebView是不能够支持上传文件的（在iOS和微信上完全正常工作）。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。

主要思路是重写WebChromeClient，然后在Activity中接收选择到的文件Uri，传给页面去上传就可以了。

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。

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

WebView设置WebChromeClient

重写WebChromeClient中关于文件选择的方法，onShowFileChooser和openFileChooser。(项目中只需要选择图片，所以加上了图片过滤。)

private WebChromeClient mWebChromeClient = new WebChromeClient() {

// android 5.0 这里需要使用android5.0 sdk

public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {

if (mFilePathCallback != null) mFilePathCallback.onReceiveValue(null);

mFilePathCallback = filePathCallback;

/**

Open Declaration String android.provider.MediaStore.ACTION_IMAGE_CAPTURE = "android.media.action.IMAGE_CAPTURE"

Standard Intent action that can be sent to have the camera application capture an image and return it.

The caller may pass an extra EXTRA_OUTPUT to control where this image will be written.

If the EXTRA_OUTPUT is not present, then a small sized image is returned as a Bitmap object in the extra field.

This is useful for applications that only need a small image.

If the EXTRA_OUTPUT is present, then the full-sized image will be written to the Uri value of EXTRA_OUTPUT.

As of android.os.Build.VERSION_CODES.LOLLIPOP, this uri can also be supplied through android.content.Intent.setClipData(ClipData).

If using this approach, you still must supply the uri through the EXTRA_OUTPUT field for compatibility with old applications.

If you don't set a ClipData, it will be copied there for you when calling Context.startActivity(Intent).

选择结果的回调

在onActivityResult中获取对应的选取文件的返回结果

public void onActivityResult(int requestCode, int resultCode, Intent data) {

if (requestCode == FILECHOOSER_RESULTCODE) {

if (null == mUploadMessage) return;

Uri result = data == null || resultCode != RESULT_OK ? null : data.getData();

if (result != null) {

String imagePath = ImageFilePath.getPath(this, result);

if (!TextUtils.isEmpty(imagePath)) result = Uri.parse("file:///" + imagePath);

}

mUploadMessage.onReceiveValue(result);

mUploadMessage = null;

} else if (requestCode == INPUT_FILE_REQUEST_CODE && mFilePathCallback != null) {

// 5.0的回调

Uri[] results = null;

if (resultCode == Activity.RESULT_OK) {

if (data == null) {

// If there is not data, then we may have taken a photo

if (mCameraPhotoPath != null) results = new Uri[] { Uri.parse(mCameraPhotoPath) };

} else {

String dataString = data.getDataString();

if (dataString != null) results = new Uri[] { Uri.parse(dataString) };

}

mFilePathCallback.onReceiveValue(results);

mFilePathCallback = null;

} else {

super.onActivityResult(requestCode, resultCode, data);

}

文件路径的获取

返回文件的解析，因为html页面需要的是文件，所以客户端需要返回的是对应文件的路径。这样，就会存在一个问题，在Android 4.4上，通过文件选择返回的结果都是对应以content开头格式的对应的路径。这就得需要咱们来进行判断，最终都需要转回成以file开头对应的格式文件。下面，我封装成了一个ImageFilePath的类，通过调用getPath方法来获取最终的结果。这个类的方法如下：

public class ImageFilePath {

/**

* Method for return file path of Gallery image

public static String getPath(final Context context, final Uri uri) {

// check here to KITKAT or new version

boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

// DocumentProvider

if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {

// ExternalStorageProvider

if (isExternalStorageDocument(uri)) {

String docId = DocumentsContract.getDocumentId(uri);

String[] split = docId.split(":");

String type = split[0];

if ("primary".equalsIgnoreCase(type)) return Environment.getExternalStorageDirectory() + "/" + split[1];

}

// DownloadsProvider

else if (isDownloadsDocument(uri)) {

String id = DocumentsContract.getDocumentId(uri);

Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

return getDataColumn(context, contentUri, null, null);

}

// MediaProvider

else if (isMediaDocument(uri)) {

String docId = DocumentsContract.getDocumentId(uri);

String[] split = docId.split(":");

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;

String selection = "_id=?";

String[] selectionArgs = new String[] { split[1] };

return getDataColumn(context, contentUri, selection, selectionArgs);

}

// MediaStore (and general)

else if ("content".equalsIgnoreCase(uri.getScheme())) {

// Return the remote address

if (isGooglePhotosUri(uri)) return uri.getLastPathSegment();

return getDataColumn(context, uri, null, null);

}

// File

else if ("file".equalsIgnoreCase(uri.getScheme())) return uri.getPath();

return null;

}

/**

* 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;

String column = "_data";

String[] projection = { column };

try {

cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);

if (cursor != null && cursor.moveToFirst()) {

int index = cursor.getColumnIndexOrThrow(column);

return cursor.getString(index);

}

} finally {

if (cursor != null) cursor.close();

}

return null;

}

public static boolean isExternalStorageDocument(Uri uri) {

return "com.android.externalstorage.documents".equals(uri.getAuthority());

}

public static boolean isDownloadsDocument(Uri uri) {

return "com.android.providers.downloads.documents".equals(uri.getAuthority());

}

public static boolean isMediaDocument(Uri uri) {

return "com.android.providers.media.documents".equals(uri.getAuthority());

}

public static boolean isGooglePhotosUri(Uri uri) {

return "com.google.android.apps.photos.content".equals(uri.getAuthority());

}

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