Android Studio - When I change the thickness of paint in my drawing app (Using a seekBar) , it changes the thickness of the paint I've already drawn

Question

I am currently creating a drawing app with Kotlin, and whenever I change the thickness of my paint (Using a seekBar), it changes the thickness of the paint I've already drawn. This is not what I intended to happen. As you might have already guessed, I only want to change the thickness of paint that the user is about to draw.

I really hope someone could help, as I have tried lots of things, and nothing has succeed, as of yet... Hope someone could turn that record around.

Here is the code for my Main Activity (It is called Collab) Just for your notice, the 'colourPicker' button, is just leading to a activity with many more buttons, of different colours. There are actually no dialogs or sharedPreferences used, I was just fiddling around with those functions.

Here is the code, itself:

package com.example.savedtrial

import android.app.Dialog
import android.content.Context
import android.content.Intent
import android.graphics.Color
import android.graphics.Paint
import android.graphics.Path
import android.graphics.drawable.ColorDrawable
import android.os.Bundle
import android.view.Window
import android.widget.ImageButton
import android.widget.ImageView
import android.widget.SeekBar
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.example.savedtrial.PaintView.Companion.colorList
import com.example.savedtrial.PaintView.Companion.currentBrush
import com.example.savedtrial.PaintView.Companion.pathList

class Collab : AppCompatActivity() {

    companion object{
        var path = Path()
        var paintBrush = Paint()
    }




    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_collab)

        val actionBar = supportActionBar

        actionBar!!.title = "Whiteboard"

        actionBar.setDisplayHomeAsUpEnabled(true)

        //saveData()


        val redBtn = findViewById<ImageButton>(R.id.redColour)
        val blackBtn = findViewById<ImageButton>(R.id.blackColour)
        val eraser = findViewById<ImageView>(R.id.eraser)
        val colourPicker = findViewById<ImageView>(R.id.colourPicker)
        val clearBoard = findViewById<ImageView>(R.id.clearBoard)
        val sharedPref = getSharedPreferences("myPref", Context.MODE_PRIVATE)
        val editor = sharedPref.edit()


        redBtn.setOnClickListener{
            Toast.makeText(this, "Red Colour Chosen", Toast.LENGTH_SHORT).show()
            paintBrush.color = Color.RED
            currentColor(paintBrush.color)
        }

            eraser.setOnClickListener{
            Toast.makeText(this, "Eraser Chosen", Toast.LENGTH_SHORT).show()
            paintBrush.color = Color.WHITE
            currentColor(paintBrush.color)

            }




        val thicknessSeekbar = findViewById<SeekBar>(R.id.thicknessSeekbar)

        thicknessSeekbar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener{


            override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
                paintBrush.strokeWidth = progress.toFloat()
                //saveData()



            }

            override fun onStartTrackingTouch(seekBar: SeekBar?) {

            }

            override fun onStopTrackingTouch(seekBar: SeekBar?) {
                //saveData()


            }


        })







        colourPicker.setOnClickListener{
            //loadData()
            val intent = Intent(this, ColourPicker::class.java)
            startActivity(intent)
            //loadData()

        }

        blackBtn.setOnClickListener{

            Toast.makeText(this, "Black Colour Chosen", Toast.LENGTH_SHORT).show()
            paintBrush.color = Color.BLACK
            currentColor(paintBrush.color)

        }

        clearBoard.setOnClickListener {
            Toast.makeText(this, "Board Cleared", Toast.LENGTH_SHORT).show()
            pathList.clear()
            colorList.clear()
            path.reset()
        }













    }

    private fun showCustomDialogBox() {

        val dialog = Dialog(this)
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)
        dialog.setCancelable(false)
        dialog.setContentView(R.layout.pick_a_colour_attempt_popup)
        dialog.window?.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))

    }


    private fun currentColor(color: Int){
        currentBrush = color
        path = Path()
    }


    private fun saveData(){
        val strokePref = paintBrush.strokeWidth.toFloat()
        //redBtn.Button = strokePref
        //blackBtn = strokePref


        val sharedPreferences = getSharedPreferences("sharedPrefs", Context.MODE_PRIVATE)
        val editor = sharedPreferences.edit()
        editor.apply {
            putFloat("STROKE_PREF", strokePref)
        }.apply()
    }


    private fun loadData() {
        val sharedPreferences = getSharedPreferences("sharedPrefs", MODE_PRIVATE)
        val savedFloat = sharedPreferences.getFloat("STROKE_PREF", 8f)

        paintBrush.strokeWidth = savedFloat


    }


}

Here is the activity of the MainActivity, just so you can better understand what I was talking about in the code above:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:background="@color/white"
    tools:context=".Collab">

    <LinearLayout
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_marginTop="10dp"
        android:layout_marginRight="20dp"
        android:layout_marginLeft="20dp"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:background="@drawable/toolbar_background"
        android:gravity="center"
        tools:ignore="MissingConstraints">

        <ImageButton
            android:id="@+id/blackColour"
            android:layout_width="50dp"
            android:layout_margin="10dp"
            android:layout_height="50dp"
            android:background="@drawable/black_background"
            android:contentDescription="Black"/>

        <ImageButton
            android:id="@+id/redColour"
            android:layout_width="50dp"
            android:layout_margin="10dp"
            android:layout_height="50dp"
            android:background="@drawable/red_background"
            android:contentDescription="Red"/>

        <ImageView
            android:id="@+id/colourPicker"
            android:layout_width="50dp"
            android:layout_margin="10dp"
            android:layout_height="50dp"
            android:src="@drawable/img_2"/>

        <ImageView
            android:id="@+id/eraser"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_marginLeft="30dp"
            app:srcCompat="@drawable/eraser_useless" />

        <ImageView
            android:id="@+id/clearBoard"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:src="@drawable/img_5"
            android:layout_marginLeft="10dp"/>


    </LinearLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/toolbar"
        tools:ignore="UnknownId">

        <include layout="@layout/paint_view"/>


    </RelativeLayout>

    <SeekBar
        android:id="@+id/thicknessSeekbar"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_below="@+id/toolbar"
        android:layout_marginTop="20dp"
        android:backgroundTint="@color/darkRED"
        android:background="@drawable/toolbar_background"
        android:layout_marginRight="10dp"
        android:layout_marginLeft="50dp"/>

    <ImageView
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:src="@drawable/draw"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="5dp"
        android:layout_below="@+id/toolbar"/>


</RelativeLayout>

This is the code for the canvas, the layout is just a blank white screen:

package com.example.savedtrial

import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.Path
import android.util.AttributeSet
import android.view.MotionEvent
import android.view.View
import android.view.ViewGroup
import androidx.constraintlayout.motion.widget.TransitionBuilder.validate
import com.example.savedtrial.Collab.Companion.paintBrush
import com.example.savedtrial.Collab.Companion.path

class PaintView: View {

    var params : ViewGroup.LayoutParams? = null

    companion object{
        var pathList = ArrayList<Path>()
        var colorList = ArrayList<Int>()
        var currentBrush = Color.BLACK

    }

    constructor(context: Context) : this(context, null){
        init()
    }
    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0){
        init()
    }

    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        init()
    }



    private fun init(){
        paintBrush.isAntiAlias = true
        paintBrush.color = currentBrush
        paintBrush.style = Paint.Style.STROKE
        paintBrush.strokeJoin = Paint.Join.ROUND
        if (paintBrush.strokeWidth == 8f) {
            true
        } else {
            true
        }

        params = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)

    }

    override fun onTouchEvent(event: MotionEvent?): Boolean {
        var x = event!!.x
        var y = event.y

        when(event.action){
            MotionEvent.ACTION_DOWN -> {
                path.moveTo(x,y)
                return true
            }
            MotionEvent.ACTION_MOVE ->{
                path.lineTo(x,y)
                pathList.add(path)
                colorList.add(currentBrush)
            }
            else -> return false
        }
        postInvalidate()
        return false

    }

    override fun onDraw(canvas: Canvas) {

        for(i in pathList.indices){
            paintBrush.color = colorList[i]
            canvas.drawPath(pathList[i], paintBrush)
            drawableStateChanged()
            invalidate()
        }



    }




}

Anyways, really hope someone can help my situation here. Good luck, and thanks for taking the time to read until the end.

Answer 1

Nevermind guys. I used ChatGPT, and by doing so, I realised it would've been way to complicated for someone to try and solve via Stack Overflow. But thanks to anyone who was considering, or trying to help!