draw function is not working while activate_btn "touched"

.idea/gradle.xml

@@ -13,7 +13,6 @@
             <option value="$PROJECT_DIR$/app" />
           </set>
         </option>
-        <option name="resolveModulePerSourceSet" value="false" />
       </GradleProjectSettings>
     </option>
   </component>

app/src/main/java/com/example/acapendulum20/canvas/Canvas.kt

@@ -1,32 +0,0 @@
-package com.example.acapendulum20.canvas
-
-import android.content.Context
-import android.graphics.Canvas
-import android.graphics.Paint
-import android.util.AttributeSet
-import android.view.View
-
-class CanvasView @JvmOverloads constructor(
-    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
-) : View(context, attrs, defStyleAttr) {
-
-
-    val paint: Paint = Paint()
-
-    override fun onDraw(canvas: Canvas?) {
-        super.onDraw(canvas)
-
-        paint.strokeWidth = 9f
-        canvas?.drawLine(455f,0f,500f, 630f,paint)
-
-    }
-    fun drawBob(canvas: Canvas?) {
-        paint.style = Paint.Style.STROKE
-        paint.strokeWidth = 10f
-        canvas?.drawCircle(500f, 700f, 70f, paint)
-    }
-
-    fun drawBob() {
-        println("hallo")
-    }
-}

app/src/main/java/com/example/acapendulum20/canvas/CanvasPendulum.kt

@@ -0,0 +1,61 @@
+package com.example.acapendulum20.canvas
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.util.AttributeSet
+import android.view.View
+
+class CanvasPendulum @JvmOverloads constructor(
+    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+
+
+    val paint: Paint = Paint()
+    lateinit var canvas: Canvas
+
+    override fun onDraw(canvas: Canvas?) {
+        super.onDraw(canvas)
+
+        //if canvas not NULL then this canvas = it
+        canvas?.let {
+            this.canvas = it
+        }
+
+    }
+
+    fun drawPendulum() {
+        paint.style = Paint.Style.STROKE
+        paint.strokeWidth = 10f
+        canvas.drawCircle(500f, 700f, 70f, paint)
+        paint.strokeWidth = 9f
+        canvas.drawLine(455f,0f,500f, 630f,paint)
+    }
+
+    fun stopDrawingPendulum() {
+        canvas.drawCircle(400f, 300f, 70f, paint)
+    }
+
+
+}
+
+
+
+
+
+
+
+
+
+
+
+
+/*<view
+        class="com.example.acapendulum20.canvas.CanvasView"
+        android:layout_width="347dp"
+        android:layout_height="440dp"
+        app:layout_constraintBottom_toTopOf="@+id/activate_btn"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.139" />*/

app/src/main/java/com/example/acapendulum20/fragments/pendulum/PendulumFragment.kt

@@ -1,42 +1,70 @@
 package com.example.acapendulum20.fragments.pendulum
 
-import android.content.Context
-import android.graphics.*
-import android.graphics.drawable.Drawable
+import android.graphics.Canvas
 import android.os.Bundle
-import android.util.AttributeSet
 import android.view.LayoutInflater
+import android.view.MotionEvent
 import android.view.View
 import android.view.ViewGroup
-import android.widget.ImageView
-import androidx.core.content.res.ResourcesCompat
+import android.widget.Button
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.ViewModelProvider
-import androidx.navigation.fragment.findNavController
 import com.example.acapendulum20.R
-import com.example.acapendulum20.canvas.CanvasView
-import com.example.acapendulum20.viewmodel.UserViewmodel
-import kotlinx.android.synthetic.main.fragment_pendulum.*
+import com.example.acapendulum20.canvas.CanvasPendulum
+import com.google.android.material.canvas.CanvasCompat
 import kotlinx.android.synthetic.main.fragment_pendulum.view.*
-import kotlinx.android.synthetic.main.fragment_update.view.*
 
 
 class PendulumFragment : Fragment() {
 
-    private lateinit var mCanvasView: CanvasView
-
     override fun onCreateView(
         inflater: LayoutInflater, container: ViewGroup?,
         savedInstanceState: Bundle?
     ): View? {
         // Inflate the layout for this fragment
         val view = inflater.inflate(R.layout.fragment_pendulum, container, false)
+        val mCanvasPendulum: CanvasPendulum
+        mCanvasPendulum = view.findViewById(R.id.canvasContainer)!!
 
         //activate the magnet
-        view.activate_btn.setOnClickListener{
-            mCanvasView.drawBob()
+        val button = view.findViewById<Button>(R.id.activate_btn)
+
+        /*
+        button.setOnClickListener{
+            mCanvasPendulum.drawBob()
+            mCanvasPendulum.drawLine()
+        }*/
+
+            button.setOnTouchListener { v, event ->
+            val action = event.action
+            when(action){
+
+                MotionEvent.ACTION_DOWN -> {
+                    mCanvasPendulum.drawPendulum()
+                }
+
+                MotionEvent.ACTION_MOVE -> { }
+
+                MotionEvent.ACTION_UP -> {
+                    mCanvasPendulum.stopDrawingPendulum()
+                }
+
+                MotionEvent.ACTION_CANCEL -> {
+
+                }
+
+                else ->{
+
+                }
+            }
+            true
         }
 
+        //System.currentTimeMillis()
+        //System.nanoTime()
+
         return view
     }
 }
+
+

app/src/main/res/layout/fragment_pendulum.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<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"
@@ -60,15 +61,6 @@
         app:layout_constraintBottom_toTopOf="@+id/textView5"
         app:layout_constraintStart_toEndOf="@+id/textView8" />
 
-    <view
-        class="com.example.acapendulum20.canvas.CanvasView"
-        android:layout_width="347dp"
-        android:layout_height="440dp"
-        app:layout_constraintBottom_toTopOf="@+id/activate_btn"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintVertical_bias="0.139" />
 
     <TextView
         android:id="@+id/textView10"
@@ -108,5 +100,15 @@
         app:layout_constraintTop_toTopOf="parent"
         app:layout_constraintVertical_bias="0.77" />
 
+    <com.example.acapendulum20.canvas.CanvasPendulum
+        android:id="@+id/canvasContainer"
+        android:layout_width="347dp"
+        android:layout_height="440dp"
+        app:layout_constraintBottom_toTopOf="@+id/activate_btn"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.139"/>
+
 
 </androidx.constraintlayout.widget.ConstraintLayout>