Webview 에 가로 스크롤바를 구현하고 싶어요

Question

Xml Source

        <com.nsdevil.ubttabletv4.views.MathView
            android:id="@+id/math_view"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginStart="10dp"
            android:layout_marginTop="10dp"
            app:math_json="@{answer.answer}"
            app:layout_constraintBottom_toBottomOf="@id/b_answer"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@id/v_guide_1"
            app:layout_constraintTop_toTopOf="parent" />

Kt Source

class MathView : WebView {
    private var text: String? = null

    @Volatile
    private var pageLoaded = false

    constructor(context: Context) : super(context) {
        init(context)
    }

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

    @SuppressLint("SetJavaScriptEnabled")
    private fun init(context: Context) {
        setBackgroundColor(Color.TRANSPARENT)
        text = ""
        pageLoaded = false

        // enable javascript
        settings.apply {
            loadWithOverviewMode = true
            javaScriptEnabled = true
            defaultFontSize = 25
            cacheMode = WebSettings.LOAD_CACHE_ELSE_NETWORK
        }

        // caching
        val dir = context.cacheDir
        if (!dir.exists()) {
            Log.d(TAG, "directory does not exist")
            val mkdirsStatus = dir.mkdirs()
            if (!mkdirsStatus) {
                Log.e(TAG, "directory creation failed")
            }
        }

        // disable click
        isClickable = false
        isLongClickable = false
        settings.useWideViewPort = true
        loadUrl("file:///android_asset/www/MathLive.html")
        webViewClient = object : WebViewClient() {
            override fun onPageFinished(view: WebView, url: String) {
                pageLoaded = true
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
                    evaluateJavascript("showFormula('$text')", null)
                } else {
                    loadUrl("javascript:showFormula('$text')")
                }
                super.onPageFinished(view, url)
            }
        }
    }

    fun setText(text: String?) {
        this.text = text
        if (pageLoaded) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
                evaluateJavascript("showFormula('" + this@MathView.text + "')", null)
            } else {
                loadUrl("javascript:showFormula('" + this@MathView.text + "')")
            }
        } else {
            Log.e(TAG, "Page is not loaded yet.")
        }
    }

    companion object {
        private val TAG = MathView::class.java.simpleName
    }
}