WebView选择图片集成，解决不可选择问题

项目内嵌webview需要进行图片选择，按常规直接给webview增加WebChromeClient。代码如下：

class MyWebChromeClient extends WebChromeClient {
        public void openFileChooser(ValueCallback<Uri> uploadMsg) {
            resetWebSelectImageCallBack();

            mUploadMsg = uploadMsg;
            selectImage();
        }

        public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {
            resetWebSelectImageCallBack();

            mUploadMsg = uploadMsg;
            selectImage();
        }

        @Override
        public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
            resetWebSelectImageCallBack();

            mUploadMsg = uploadMsg;
            selectImage();
        }

        @Override
        public boolean onShowFileChooser(WebView webView,
                                         ValueCallback<Uri[]> valueCallback,
                                         FileChooserParams fileChooserParams) {
            resetWebSelectImageCallBack();

            mValueCallback = valueCallback;
            selectImage();
            return true;
        }
    }

选择图片后，将数据通过回调返回webview：

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    
    if (WebViewContract.SELECT_FILE_REQ == requestCode) {
        if (Activity.RESULT_OK != resultCode) {
            resetWebSelectImageCallBack();
            return;
        }

        if (null != mUploadMsg) {
            mUploadMsg.onReceiveValue(UriUtils.file2Uri(new File(FileConstants.IMAGE_TEMP)));
            mUploadMsg = null;
        }

        if (null != mValueCallback) {
            mValueCallback.onReceiveValue(new Uri[]{UriUtils.file2Uri(new File(FileConstants.IMAGE_TEMP))});
            mValueCallback = null;
        }
    }
}

选择图片没有什么好说的，但是一定注意一个点：在未成功回调数据给webview时，一定返回一个null。否则下次调用时，是无法进入方法的！

我这边的处理方法是调用resetWebSelectImageCallBack()：

private void resetWebSelectImageCallBack() {
    if (null != mUploadMsg) {
        mUploadMsg.onReceiveValue(null);
        mUploadMsg = null;
    }

    if (null != mValueCallback) {
        mValueCallback.onReceiveValue(null);
        mValueCallback = null;
    }
}