Checking empty string in kotlin doesn't work - string

Question

i am begginer into kotlin development and i am doing a simple TicTacToe game with kotlin and i want to check if the first three button texts are equal and at the same time one of them is not empty but when i use !button1.text.toString().isEmpty it doesn't work. don't know why. help me. here are my kotlin and xml codes
package com.example.tictac
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_tic_tac.*
class TicTacActivity : AppCompatActivity() {
var isFirstPlayer = true;
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_tic_tac)
init()
}
fun init() {
buttonClick(button1)
buttonClick(button2)
buttonClick(button3)
buttonClick(button4)
buttonClick(button5)
buttonClick(button6)
buttonClick(button7)
buttonClick(button8)
buttonClick(button9)
}
fun buttonClick(button: Button) {
button.setOnClickListener() {
if (isFirstPlayer) {
button.text = "X"
isFirstPlayer = false
} else {
button.text = "O"
isFirstPlayer = true
}
button.isClickable = false
}
if (!button1.text.toString().isEmpty() &&
button1.text.toString().equals(button2.text.toString()) &&
button2.text.toString().equals(button3.text.toString())) {
winner(button1)
}
}
fun winner(button: Button) {
Toast.makeText(this, button.text.toString(), Toast.LENGTH_LONG).show()
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".TicTacActivity"
android:orientation="vertical"
>
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1">
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"
/>
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"
/>
<Button
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
</LinearLayout>
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1">
<Button android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
<Button android:id="#+id/button5"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
<Button android:id="#+id/button6"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
</LinearLayout>
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1">
<Button android:id="#+id/button7"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
<Button android:id="#+id/button8"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
<Button android:id="#+id/button9"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="49sp"/>
</LinearLayout>
</LinearLayout>

Answer 1

You must include the code that you think it does not work inside button.setOnClickListener so it is executed every time you click on a button.
Of course you have to add more code to check other cases.
fun buttonClick(button: Button) {
button.setOnClickListener() {
if (isFirstPlayer) {
button.text = "X"
isFirstPlayer = false
} else {
button.text = "O"
isFirstPlayer = true
}
button.isClickable = false
if (!button1.text.toString().isEmpty() &&
button1.text.toString().equals(button2.text.toString()) &&
button2.text.toString().equals(button3.text.toString())) {
winner(button1)
}
}
}