[Kotlin] Seekbar with java or kotlin

Android TextView by Kotlin

Kotlin 開發第 2 天 Discount (Seekbar + Keyboard)

看了別人kotlin 在2017的教學，我照做就是會閃退

查了kotlin的寫法，更確定在課堂上學的這個寫法了

Java的寫法是 settext

而kotlin是TextView.text =

沒想到光是改成kotlin的寫法就不會閃退了，困惑

blogger不能夠方便的放上程式碼，想跑路啦

原來有個插件可以用，但還是些微的麻煩

<?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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:text="打折比例(%)"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.149"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editnumber"
        app:layout_constraintVertical_bias="0.0" />

    <EditText
        android:id="@+id/editnumber"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="160dp"
        android:ems="10"
        android:inputType="number"
        android:text="$0.00"
        android:textSize="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.447"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="48dp"
        android:layout_marginLeft="48dp"
        android:layout_marginTop="28dp"
        android:text="打折後價格"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView4" />

    <TextView
        android:id="@+id/percent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="44dp"
        android:layout_marginLeft="44dp"
        android:layout_marginTop="15dp"
        android:text="0%"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView4"
        app:layout_constraintTop_toBottomOf="@+id/editnumber"
        app:layout_constraintVertical_bias="0.0" />

    <TextView
        android:id="@+id/money"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="60dp"
        android:layout_marginLeft="60dp"
        android:layout_marginTop="29dp"
        android:text="0"
        app:layout_constraintStart_toEndOf="@+id/textView"
        app:layout_constraintTop_toBottomOf="@+id/percent" />

    <SeekBar
        android:id="@+id/seekBar"
        android:layout_width="253dp"
        android:layout_height="47dp"
        android:layout_marginTop="144dp"
        android:layout_marginEnd="96dp"
        android:layout_marginRight="96dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editnumber" />


</androidx.constraintlayout.widget.ConstraintLayout>




package com.example.seekbarpercentage

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import android.widget.EditText
import android.widget.SeekBar
import android.widget.TextView

class MainActivity : AppCompatActivity() {
    private lateinit var money : TextView
    private lateinit var percentage : TextView
    private lateinit var seekBar: SeekBar
    private lateinit var editnumber: EditText
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        money = findViewById<TextView>(R.id.money)
        percentage = findViewById<TextView>(R.id.percent)
        seekBar = findViewById<SeekBar>(R.id.seekBar)
        editnumber = findViewById<EditText>(R.id.editnumber)
        var pg = 0
        editnumber.setText("0")

        // progressBar
        seekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener{
            override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
                percentage.text = "$progress%"
                money.text = "${editnumber.text.toString().toFloat() * progress/100}"
                pg= progress
                //pg 為外部自定義變數，用來儲存 progress 供其他地方使用
            }
            override fun onStartTrackingTouch(p0: SeekBar?) {}
            override fun onStopTrackingTouch(p0: SeekBar?) {}
        })
        editnumber.addTextChangedListener(object : TextWatcher {
            override fun afterTextChanged(s: Editable?) {
            }

            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
            }

            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
                if(editnumber.text.toString() != "")
                    money.setText("${editnumber.text.toString().toFloat() * (pg/100)}")
                else money.text = "0"
            }
        })
    }

}