How to disable dot button in android Kotlin - kotlin

Question

I am new to Android Studio - Kotlin, I am building an app with numbers and math operators with decimal point(.dot button)In my math calculator app, if press the dot button, the button should be disabled or not entered for the second time. I want to disable or stop printing dot button(.) if pressed more than once.
Here is my code
Acitivity.kt file
package com.tripbegins.calculator
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button
import com.tripbegins.calculator.R.id.*
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
var emptyText = true
fun numberEvents(view: View) {
var checkButton:Boolean = false
if(emptyText){
viewResult.setText("")
}
emptyText = false
var button = view as Button
var isClicked = viewResult.text.toString()
when (button.id) {
buttonOne.id -> isClicked += "1"
buttonTwo.id -> isClicked += "2"
buttonThree.id -> isClicked += "3"
dotButton.id-> isClicked+="."
}
viewResult.setText(isClicked)
}
var operation ="+"
var oldValues:String? = null
fun mathOperation(view: View){
var mathButton = view as Button
var isClicked = viewResult.text.toString()
when(mathButton.id){
plusButton.id-> {
operation = "+"
}
minusButton.id->{
operation="-"
}
mulButton.id->{
operation="*"
}
}
oldValues = viewResult.text.toString()
emptyText = true
}
fun Calculate(view: View){
var newValues = viewResult.text.toString()
var calulateButton:Double? = null
when(operation){
"+"-> { calulateButton = oldValues!!.toDouble() + newValues.toDouble() }
"-"-> { calulateButton = oldValues!!.toDouble() - newValues.toDouble() }
"*"-> { calulateButton = oldValues!!.toDouble() * newValues.toDouble() }
}
viewResult.setText(calulateButton.toString())
emptyText=true
}
fun clearFunction(view: View){
viewResult.setText("")
}
}
activity.xml file
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
tools:context="com.tripbegins.calculator.MainActivity">
<EditText
android:id="#+id/viewResult"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="42dp"
android:ems="10"
android:gravity="bottom|right"
android:inputType="textPersonName"
android:text="0"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/buttonTwo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="76dp"
android:onClick="numberEvents"
android:text="2"
app:layout_constraintStart_toEndOf="#+id/buttonOne"
app:layout_constraintTop_toBottomOf="#+id/viewResult" />
<Button
android:id="#+id/plusButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="38dp"
android:onClick="mathOperation"
android:text="+"
app:layout_constraintBaseline_toBaselineOf="#+id/minusButton"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/minusButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="12dp"
android:layout_marginTop="33dp"
android:onClick="mathOperation"
android:text="-"
app:layout_constraintStart_toEndOf="#+id/plusButton"
app:layout_constraintTop_toBottomOf="#+id/buttonTwo" />
<Button
android:id="#+id/mulButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="26dp"
android:onClick="mathOperation"
android:text="*"
app:layout_constraintBaseline_toBaselineOf="#+id/minusButton"
app:layout_constraintStart_toEndOf="#+id/minusButton" />
<Button
android:id="#+id/calButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="44dp"
android:onClick="Calculate"
android:text="Calculate"
app:layout_constraintStart_toStartOf="#+id/minusButton"
app:layout_constraintTop_toBottomOf="#+id/minusButton" />
<Button
android:id="#+id/buttonThree"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="26dp"
android:onClick="numberEvents"
android:text="3"
app:layout_constraintBaseline_toBaselineOf="#+id/buttonTwo"
app:layout_constraintStart_toEndOf="#+id/buttonTwo" />
<Button
android:id="#+id/buttonOne"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="34dp"
android:onClick="numberEvents"
android:text="1"
app:layout_constraintBaseline_toBaselineOf="#+id/buttonTwo"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/dotButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="22dp"
android:onClick="numberEvents"
android:text="."
app:layout_constraintBaseline_toBaselineOf="#+id/calButton"
app:layout_constraintEnd_toStartOf="#+id/calButton" />
<Button
android:id="#+id/clearButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="11dp"
android:onClick="clearFunction"
android:text="Clear"
app:layout_constraintBaseline_toBaselineOf="#+id/calButton"
app:layout_constraintStart_toEndOf="#+id/calButton" />
</android.support.constraint.ConstraintLayout>
My expectation of the result
Valid entry -> 3. (.dot button should not be entered for the second time)
Invalid entry -> 3... (currently i can able to enter multiple .dot buttons)
Dot button should not pressed twice. It should be active only once.
Thanks
Mohammed

Answer 1

so you want to disable the button that has the name dotButton after the user clicks it for the first time :
to disable a button, use:
dotButton.isClickable=false
if you want the button to become clickable again(like when the user deletes the dot that he already pressed) you can use:
dotButton.isClickable=true
Edit:
modify your activity code like that :
when (button.id) {
buttonOne.id -> isClicked += "1"
buttonTwo.id -> isClicked += "2"
buttonThree.id -> isClicked += "3"
dotButton.id-> {
isClicked+="."
dotButton.isClickable=false//**add this line here**
}
}
fun clearFunction(view: View){
viewResult.setText("")
dotButton.isClickable=true//**add this line here**
}