自定义小部件不呈现

我创建我的活动：

class ActivityMain : AppCompatActivity() {
    private var count = 0

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

        binder()
    }


    private fun binder() {
        val button_addButton = findViewById<Button>(R.id.button_addButton)
        val button_addCustomWidget = findViewById<Button>(R.id.button_addCustomWidget)

        val layout = findViewById<LinearLayout>(R.id.testLayout)
        val scrollView = findViewById<ScrollView>(R.id.testScroll)

        val upButton = findViewById<Button>(R.id.upButton)
        val downButton = findViewById<Button>(R.id.downButton)

        upButton.setOnClickListener {
            scrollView.fullScroll(ScrollView.FOCUS_UP)
        }
        downButton.setOnClickListener {
            scrollView.fullScroll(ScrollView.FOCUS_DOWN)
        }

        button_addCustomWidget.setOnClickListener {
            val widget = ChannelMessageWidget(this, null, 0)

            widget.setLayoutParams(LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.WRAP_CONTENT
            ))

            widget.setAvatar(
                BitmapFactory.decodeResource(getResources(),
                R.drawable.default_avatar))

            layout.addView(widget)
        }

        button_addButton.setOnClickListener {
            count ++

            val button = Button(this)

            button.text = "Кнопка $count!"

            button.setOnClickListener {
                Toast.makeText(this, "Привет, $count", Toast.LENGTH_SHORT).show()
            }

            layout.addView(button)
        }
    }
}

所有小部件均已初始化并出现一个窗口。这是它的 XML：

<?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=".ActivityMain">

    <Button
        android:id="@+id/button_addButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="AB"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <ScrollView
        android:id="@+id/testScroll"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@+id/button_addButton"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <LinearLayout
            android:id="@+id/testLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            tools:ignore="UselessLeaf" />
    </ScrollView>

    <Button
        android:id="@+id/upButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Up"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/button_addCustomWidget"
        app:layout_constraintStart_toEndOf="@+id/downButton" />

    <Button
        android:id="@+id/downButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Down"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/button_addCustomWidget"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ACW"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/button_addButton"
        app:layout_constraintStart_toEndOf="@+id/upButton" />
</androidx.constraintlayout.widget.ConstraintLayout>

我还创建了一个自定义小部件（我正在尝试绘制圆形图片）：

fun dp2pixel(dp: Float, context: Context): Float {
    return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, context.resources.displayMetrics)
}

class ChannelMessageWidget @JvmOverloads constructor(
    private val context: Context, attrs: AttributeSet? = null, defStyleAttr: Int
) : View(context, attrs, defStyleAttr) {
    private var text: String = "null"
    private lateinit var avatar: Bitmap
    private var displayed = false
    private val radius = 128f

//    @SuppressLint("DrawAllocation")
//    override fun onDraw(canvas: Canvas) {
//        super.onDraw(canvas)
//
//        val scaledBitmap = Bitmap.createScaledBitmap(avatar, dp2pixel(radius, context).toInt(), dp2pixel(radius, context).toInt(), true)
//
//        val outputBitmap = Bitmap.createBitmap(scaledBitmap.width, scaledBitmap.height, Bitmap.Config.ARGB_8888)
//
//        val paint = Paint().apply {
//            isAntiAlias = true
//            color = Color.BLACK
//            style = Paint.Style.FILL
//        }
//
//        val radius = scaledBitmap.width / 2f
//        canvas.drawCircle(radius, radius, radius, paint)
//
//        paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
//        canvas.drawBitmap(outputBitmap, 0f, 0f, paint)
//
//        val rect = Rect(0f, 0f, scaledBitmap.width.toFloat(), scaledBitmap.height.toFloat())
//
//        displayed = true
//    }

//    @SuppressLint("DrawAllocation")
//    override fun onDraw(canvas: Canvas) {
//        super.onDraw(canvas)
//
//        val scaledBitmap = Bitmap.createScaledBitmap(avatar, dp2pixel(radius, context).toInt(), dp2pixel(radius, context).toInt(), true)
//
//        val outputBitmap = Bitmap.createBitmap(scaledBitmap.width, scaledBitmap.height, Bitmap.Config.ARGB_8888)
//        val outputCanvas = Canvas(outputBitmap) // Создаем Canvas для outputBitmap
//
//        val paint = Paint().apply {
//            isAntiAlias = true
//            color = Color.BLACK
//            style = Paint.Style.FILL
//        }
//
//        val radius = scaledBitmap.width / 2f
//        outputCanvas.drawCircle(radius, radius, radius, paint) // Рисуем круг на outputCanvas
//
//        paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
//        outputCanvas.drawBitmap(scaledBitmap, 0f, 0f, paint) // Рисуем отмасштабированное изображение на outputCanvas
//
//        canvas.drawBitmap(outputBitmap, 0f, 0f, null) // Рисуем outputBitmap на холсте canvas
//    }

    @SuppressLint("DrawAllocation")
    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)

        val paint = Paint().apply {
            isAntiAlias = true
            color = Color.BLACK
            style = Paint.Style.FILL
        }

        val rect = Rect(0, 0, 100, 50) // Прямоугольник с шириной экрана и высотой 50 пикселей

        canvas.drawRect(rect, paint) // Отрисовка прямоугольника на холсте
    }


    fun setAvatar(avatar: Bitmap) {
        this.avatar = avatar
    }

    fun setText(text: String) {
        this.text = text
    }
}

这些方法都不起作用。控制台不显示任何错误，我的自定义元素也没有添加到布局中。虽然按钮很容易添加、滚动等。