混合开发 webview 中file 控件 点击后无反应解决方法

mWebView.setWebChromeClient(new WebChromeClient() {
            public void openFileChooser(ValueCallback<Uri> uploadMsg,
                    String acceptType, String capture) {
                   mUploadMessage = uploadMsg;
                   Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
                   intent.addCategory(Intent.CATEGORY_OPENABLE);
                   intent.setType("image/*");
                   MainActivity.this.startActivityForResult(
                     Intent.createChooser(intent, "完成操作需要使用"),
                     FILE_SELECTED);
            }
        });

@Override
protected void onActivityResult(int requestCode, int resultCode,
        Intent intent) {

    switch (requestCode) {

    // Choose a file from the file picker.
    case FILE_SELECTED:
        if (null == mUploadMessage)
            break;
        Uri result = intent == null || resultCode != RESULT_OK ? null
                : intent.getData();
        mUploadMessage.onReceiveValue(result);
        mUploadMessage = null;
        break;
    }
}