Q. Kotlin for Android Developement: Text Field to TextView?

I started learning to develop Android applications in Kotlin 2 weeks ago. I'm currently trying to make some changes to my tip calculator application, and trying to display the text field input into a totalCost TextView (where you see the "Cost of Service" text below the "Tip Amount: $20.00"), but I've no idea how to go about doing that.

Click here to see the app layout

And here's the code:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>  <androidx.constraintlayout.widget.ConstraintLayout 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"      android:padding="16dp"      tools:context=".MainActivity">        <ImageView          android:id="@+id/icon_cost_of_service"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:importantForAccessibility="no"          app:srcCompat="@drawable/ic_store"          app:layout_constraintStart_toStartOf="parent"          app:layout_constraintTop_toTopOf="@id/cost_of_service"          app:layout_constraintBottom_toBottomOf="@id/cost_of_service"/>        <com.google.android.material.textfield.TextInputLayout          android:id="@+id/cost_of_service"          android:layout_width="160dp"          android:layout_height="wrap_content"          android:hint="@string/cost_of_service"          android:layout_marginStart="16dp"          app:layout_constraintStart_toEndOf="@id/icon_cost_of_service"          app:layout_constraintTop_toTopOf="parent" >            <com.google.android.material.textfield.TextInputEditText              android:id="@+id/cost_of_service_edit_text"              android:layout_width="match_parent"              android:layout_height="wrap_content"              android:inputType="numberDecimal"/>      </com.google.android.material.textfield.TextInputLayout>        <ImageView          android:id="@+id/icon_service_question"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:importantForAccessibility="no"          app:srcCompat="@drawable/ic_service"          app:layout_constraintStart_toStartOf="parent"          app:layout_constraintTop_toTopOf="@id/service_question"          app:layout_constraintBottom_toBottomOf="@id/service_question"/>        <TextView          android:id="@+id/service_question"          style="@style/Widget.TipTime.TextView"          android:layout_marginTop="16dp"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:text="@string/how_was_the_service"          app:layout_constraintStart_toStartOf="@id/cost_of_service"          app:layout_constraintTop_toBottomOf="@id/cost_of_service" />        <RadioGroup          android:id="@+id/tip_options"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:checkedButton="@id/option_twenty_percent"          android:orientation="vertical"          app:layout_constraintStart_toStartOf="@id/service_question"          app:layout_constraintTop_toBottomOf="@id/service_question">            <RadioButton              android:id="@+id/option_twenty_percent"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:text="@string/amazing_service" />            <RadioButton              android:id="@+id/option_eighteen_percent"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:text="@string/good_service" />            <RadioButton              android:id="@+id/option_fifteen_percent"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:text="@string/ok_service" />      </RadioGroup>        <ImageView          android:id="@+id/icon_round_up"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:importantForAccessibility="no"          app:srcCompat="@drawable/ic_round_up"          app:layout_constraintStart_toStartOf="parent"          app:layout_constraintTop_toTopOf="@id/round_up_switch"          app:layout_constraintBottom_toBottomOf="@id/round_up_switch"/>          <com.google.android.material.switchmaterial.SwitchMaterial          android:id="@+id/round_up_switch"          android:layout_width="0dp"          android:layout_height="wrap_content"          android:checked="true"          android:text="@string/round_up_tip"          app:layout_constraintEnd_toEndOf="parent"          android:layout_marginStart="16dp"          app:layout_constraintStart_toEndOf="@id/icon_round_up"          app:layout_constraintTop_toBottomOf="@id/tip_options" />        <Button          android:id="@+id/calculate_button"          android:layout_width="0dp"          android:layout_height="wrap_content"          android:text="@string/calculate"          android:layout_marginTop="8dp"          app:layout_constraintEnd_toEndOf="parent"          app:layout_constraintStart_toStartOf="@id/round_up_switch"          app:layout_constraintTop_toBottomOf="@id/round_up_switch" />        <TextView          android:id="@+id/tip_result"          style="@style/Widget.TipTime.TextView"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:layout_marginTop="8dp"          app:layout_constraintEnd_toEndOf="parent"          app:layout_constraintTop_toBottomOf="@id/calculate_button"          tools:text="Tip Amount: $10" />    </androidx.constraintlayout.widget.ConstraintLayout>  

MainActivity.kt

package com.example.tiptime    import android.os.Bundle  import androidx.appcompat.app.AppCompatActivity  import com.example.tiptime.databinding.ActivityMainBinding  import java.text.NumberFormat    class MainActivity : AppCompatActivity() {        private lateinit var binding: ActivityMainBinding        override fun onCreate(savedInstanceState: Bundle?) {          super.onCreate(savedInstanceState)            binding = ActivityMainBinding.inflate(layoutInflater)          setContentView(binding.root)            binding.calculateButton.setOnClickListener { calculateTip() }      }            fun calculateTip() {          val stringInTextField = binding.costOfServiceEditText.text.toString()          val cost = stringInTextField.toDoubleOrNull()          if (cost == null) {              binding.tipResult.text = ""              return          }                    val tipPercentage = when (binding.tipOptions.checkedRadioButtonId) {              R.id.option_twenty_percent -> 0.20              R.id.option_eighteen_percent -> 0.18              else -> 0.15          }            var tip = tipPercentage * cost          if (binding.roundUpSwitch.isChecked) {              tip = kotlin.math.ceil(tip)          }            val formattedTip = NumberFormat.getCurrencyInstance().format(tip)          binding.tipResult.text = getString(R.string.tip_amount, formattedTip)      }    }  

Thank you.

https://stackoverflow.com/questions/66913311/q-kotlin-for-android-developement-text-field-to-textview April 02, 2021 at 09:07AM