1. 在AndroidManifest.xml文件中添加权限

2. 在WebViewClient中使用onShowFileChooser()方法接收上传请求

    private ValueCallback mUploadMessage;
    private static final int REQUEST_SELECT_FILE = 100;

    @Override
    public boolean onShowFileChooser(WebView webView, ValueCallback filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
        if (mUploadMessage != null) {
            mUploadMessage.onReceiveValue(null);
        }
        mUploadMessage = filePathCallback;
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (intent.resolveActivity(webView.getContext().getPackageManager()) != null) {
            File photoFile = null;
            try {
                photoFile = createImageFile();
            } catch (IOException ex) {
            }
            if (photoFile != null) {
                mCapturedImageUri = FileProvider.getUriForFile(webView.getContext(), webView.getContext().getApplicationContext().getPackageName() + ".provider", photoFile);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, mCapturedImageUri);
            } else {
                intent = null;
            }
        }
        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType("image/*");
        Intent chooserIntent = Intent.createChooser(i, "Image Chooser");
        if (intent != null) {
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, new Parcelable[]{intent});
        }
        startActivityForResult(chooserIntent, REQUEST_SELECT_FILE);
        return true;
    }

    private File createImageFile() throws IOException {
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = webView.getContext().getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        File image = File.createTempFile(imageFileName, ".jpg", storageDir);
        mCameraImagePath = "file:" + image.getAbsolutePath();
        return image;
    }

3. 在