How do I get my logarithm and ln in Kotlin?

Question

I built a calculator with Kotlin, but I have a problem when I want to logarithm and get ln

I get the following error when I run my program and want to get my logarithm

invalid Double :

this my code

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical">

<TextView
    android:id="@+id/tvResult"
    android:layout_width="match_parent"
    android:layout_height="70dp"
    android:textSize="30sp"
    android:textColor="@color/black"
    android:gravity="start"
    android:maxLines="1"/>

<TextView
    android:id="@+id/tvExpress"
    android:layout_width="match_parent"
    android:layout_height="90dp"
    android:textSize="50sp"
    android:textColor="@color/black"
    android:gravity="start"
    android:maxLines="1"/>


<androidx.cardview.widget.CardView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:cardCornerRadius="4dp"
    app:cardElevation="2dp"
    app:cardBackgroundColor="@color/black">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:weightSum="7"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:weightSum="4"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvClear"
                style="@style/ButtonConverter"
                android:text="AC" />

            <TextView
                android:id="@+id/tvBackspace"
                style="@style/ButtonConverter"
                android:text="C" />

            <TextView
                android:id="@+id/tvOpen"
                style="@style/ButtonConverter"
                android:text="(" />

            <TextView
                android:id="@+id/tvClose"
                style="@style/ButtonConverter"
                android:text=")" />

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:weightSum="5"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvSinus"
                style="@style/ButtonConverter"
                android:text="Sin" />

            <TextView
                android:id="@+id/tvCosine"
                style="@style/ButtonConverter"
                android:text="Cos" />

            <TextView
                android:id="@+id/tvTangent"
                style="@style/ButtonConverter"
                android:text="Tan" />

            <TextView
                android:id="@+id/tvLog"
                style="@style/ButtonConverter"
                android:text="Log" />

            <TextView
                android:id="@+id/tvLn"
                style="@style/ButtonConverter"
                android:text="ln" />

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:weightSum="5"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvSquared"
                style="@style/ButtonConverter"
                android:text="x!" />

            <TextView
                android:id="@+id/tvSquare"
                style="@style/ButtonConverter"
                android:text="x²" />

            <TextView
                android:id="@+id/tvRadical"
                style="@style/ButtonConverter"
                android:text="√" />

            <TextView
                android:id="@+id/tvInv"
                style="@style/ButtonConverter"
                android:text="1/x" />

            <TextView
                android:id="@+id/tvDivide"
                style="@style/ButtonConverter"
                android:text="÷" />

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:weightSum="4"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvSeven"
                style="@style/ButtonNumber"
                android:text="7" />

            <TextView
                android:id="@+id/tvEight"
                style="@style/ButtonNumber"
                android:text="8" />

            <TextView
                android:id="@+id/tvNine"
                style="@style/ButtonNumber"
                android:text="9" />

            <TextView
                android:id="@+id/tvMul"
                style="@style/ButtonConverter"
                android:text="*" />

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:weightSum="4"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvFour"
                style="@style/ButtonNumber"
                android:text="4" />

            <TextView
                android:id="@+id/tvFive"
                style="@style/ButtonNumber"
                android:text="5" />

            <TextView
                android:id="@+id/tvSix"
                style="@style/ButtonNumber"
                android:text="6" />

            <TextView
                android:id="@+id/tvMinus"
                style="@style/ButtonConverter"
                android:text="-" />

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:weightSum="4"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvOne"
                style="@style/ButtonNumber"
                android:text="1" />

            <TextView
                android:id="@+id/tvTwo"
                style="@style/ButtonNumber"
                android:text="2" />

            <TextView
                android:id="@+id/tvThree"
                style="@style/ButtonNumber"
                android:text="3" />

            <TextView
                android:id="@+id/tvPlus"
                style="@style/ButtonConverter"
                android:text="+" />

        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/tvP"
                style="@style/ButtonNumber"
                android:text="π" />

            <TextView
                android:id="@+id/tvZero"
                style="@style/ButtonNumber"
                android:text="0" />

            <TextView
                android:id="@+id/tvDot"
                style="@style/ButtonNumber"
                android:text="." />

            <TextView
                android:id="@+id/tvEquals"
                style="@style/ButtonConverter"
                android:text="=" />

        </LinearLayout>

    </LinearLayout>

</androidx.cardview.widget.CardView>

and

MainActivity.kt

class MainActivity : AppCompatActivity() {
@SuppressLint("SetTextI18n")
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    //numbers
    tvZero.setOnClickListener { appOnExpression("0" , true) }
    tvOne.setOnClickListener { appOnExpression("1" , true) }
    tvTwo.setOnClickListener { appOnExpression("2" , true) }
    tvThree.setOnClickListener { appOnExpression("3" , true) }
    tvFour.setOnClickListener { appOnExpression("4" , true) }
    tvFive.setOnClickListener { appOnExpression("5" , true) }
    tvSix.setOnClickListener { appOnExpression("6" , true) }
    tvSeven.setOnClickListener { appOnExpression("7" , true) }
    tvEight.setOnClickListener { appOnExpression("8" , true) }
    tvNine.setOnClickListener { appOnExpression("9" , true) }
    tvDot.setOnClickListener { appOnExpression("." , true) }

    //unit converter
    tvPlus.setOnClickListener { appOnExpression("+" , false) }
    tvMinus.setOnClickListener { appOnExpression("-" , false) }
    tvMul.setOnClickListener { appOnExpression("*" , false) }
    tvDivide.setOnClickListener { appOnExpression("/" , false) }
    tvP.setOnClickListener { appOnExpression("π" , false) }

    tvP.setOnClickListener {
        if (tvExpress.text.toString().isEmpty()) {
            tvExpress.text = tvExpress.text.toString()+3.14
        }else {
            tvExpress.text = "3.14"
        }
    }

    tvSinus.setOnClickListener {
        tvExpress.text = tvExpress.text.toString()+"sin"
    }

    tvCosine.setOnClickListener {
        tvExpress.text = tvExpress.text.toString()+"cos"
    }

    tvTangent.setOnClickListener {
        tvExpress.text = tvExpress.text.toString()+"tan"
    }

    tvLog.setOnClickListener {
        tvExpress.text = tvExpress.text.toString()+"log"
    }

    tvLn.setOnClickListener {
        tvExpress.text = "ln"
    }

    tvInv.setOnClickListener {
        tvExpress.text = tvExpress.text.toString()+"^"+"(-1)"
    }

    tvSquare.setOnClickListener {
        if (tvExpress.text.toString().isEmpty()) {
            Toast.makeText(applicationContext , "عدد مورد نظر را وارد کنید" , Toast.LENGTH_LONG).show()
        }else {
            val d = tvExpress.text.toString().toLong()
            val square = d * d
            tvExpress.text = square.toString()
            tvResult.text = "$d²"
        }
    }

    tvSquared.setOnClickListener {
        if (tvExpress.text.toString().isEmpty()) {
            Toast.makeText(applicationContext , "لطفا عدد مورد نظر خود را وارد کنید" , Toast.LENGTH_LONG).show()
        }else {
            fun factorial(n: Int) : Int {
                return if (n == 0 || n == 1) 1 else n * factorial(n - 1)
            }
            val value : Int = tvExpress.text.toString().toInt()
            val fact : Int = factorial(value)
            tvExpress.text = fact.toString()
            tvResult.text = "$value'!"
        }
    }

    tvRadical.setOnClickListener {
        if (tvExpress.text.toString().isNotEmpty()) {
            Toast.makeText(applicationContext , "عدد مورد نظر را وارد کنید" , Toast.LENGTH_LONG).show()
        }else {
            val str = tvExpress.text.toString()
            val r = sqrt(str.toDouble())
            val unit = r.toLong()
            val result = unit.toString()
            tvExpress.text = result
        }
    }

    tvBackspace.setOnClickListener {
        val strNumber = tvExpress.text.toString()
        if (strNumber.isNotEmpty()) {
            tvExpress.text = strNumber.substring(0, strNumber.length - 1)
        }
    }

    tvClear.setOnClickListener {
        tvResult.text = ""
        tvExpress.text = ""
    }

    tvEquals.setOnClickListener {
        val express = ExpressionBuilder(tvExpress.text.toString()).build()
        val result = express.evaluate()
        val longResult = result.toLong()
        if (result == longResult.toDouble()) {
            try {
                tvExpress.text = longResult.toString()
            }catch (e: Exception) {
                Log.e("check" , e.message.toString())
            }
        }else {
            tvExpress.text = result.toString()
        }
    }
}
private fun appOnExpression(str: String , bool: Boolean) {
    if (tvResult.text.isNotEmpty()) {
        tvExpress.text = ""
    }
    if (bool) {
        tvResult.text = ""
        tvExpress.append(str)
    }else {
        tvExpress.append(tvResult.text)
        tvExpress.append(str)
        tvResult.text = ""
    }
}

}

I used this library

dependencies {
implementation 'net.objecthunter:exp4j:0.4.8'  
}

How can I define a value so that logarithm and ln are received in my calculator and I can get the value I enter in the calculator?