我有一个自定义网络视图。

class NewWebView : WebView {
private val name = "Android"
private var mOnScrollChangedCallback: OnScrollChangedCallback? = null
private var onJSEventListener: OnJSEventListener? = null

constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs) {
    prepareWebView()
}

constructor(context: Context?) : super(context) {
    prepareWebView()
}

constructor(context: Context?, attrs: AttributeSet?, defStyle: Int) : super(context, attrs, defStyle) {
    prepareWebView()
}

@SuppressLint("SetJavaScriptEnabled")
private fun prepareWebView() {
    addJavascriptInterface(WebAppInterface(), name)
    settings.javaScriptEnabled = true
    settings.domStorageEnabled = true
    settings.javaScriptCanOpenWindowsAutomatically = true
    webViewClient = NewWebViewClient()
}

fun setOnJSEventListener(onJSEventListener: OnJSEventListener?) {
    this.onJSEventListener = onJSEventListener
}

fun loadPage(url: String?) {
    val headerMap: MutableMap<String, String> = HashMap()
    headerMap["My-App"] = "android"
    loadUrl(url, headerMap)
}

override fun onScrollChanged(l: Int, t: Int, oldl: Int, oldt: Int) {
    super.onScrollChanged(l, t, oldl, oldt)
    if (mOnScrollChangedCallback != null) mOnScrollChangedCallback!!.onScroll(l, t)
}

private var contentHeight = 0
override fun getContentHeight(): Int {
    if (contentHeight == 0) contentHeight = computeVerticalScrollRange()
    return super.getContentHeight()
}

fun setOnScrollChangedCallback(onScrollChangedCallback: OnScrollChangedCallback?) {
    mOnScrollChangedCallback = onScrollChangedCallback
}

interface OnScrollChangedCallback {
    fun onScroll(l: Int, t: Int)
}

internal inner class WebAppInterface {
    @JavascriptInterface
    fun finish() {
        if (onJSEventListener != null) {
            onJSEventListener!!.onJSEvent("JS_FINISH")
        }
    }
}

interface OnJSEventListener {
    fun onJSEvent(event: String?)
    fun onJSEvent(event: String?, param: String?)
}

open class NewWebViewClient : WebViewClient() {
    override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
        val headerMap: MutableMap<String, String> = HashMap()
        headerMap[" My-App"] = "android"
        view?.let { webView ->
            request?.let {
                webView.loadUrl(it.url.toString(), headerMap)
            }
        }
        return true
    }
}

}
当我在活动中使用webwiew时，复制和粘贴的上下文菜单会出现，这样我就可以从webview复制文本。但是，当我在服务上使用相同的webview时，上下文菜单不会出现。我看到其他人在stackoverflow上也遇到了这个问题，但仍然没有解决方案。
在服务上使用webview时，如何在webview上启用文本选择？