[AndroidStudio] CustomView

MainActivity.kt

class MainActivity : AppCompatActivity() {
    val binding by lazy {
        ActivityMainBinding.inflate(layoutInflater)
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        // 객체 생성
        val customView = CustomView(this)
        // frameLayout 에 customView 추가
        binding.frameLayout.addView(customView)
    }
}

class CustomView(context: Context) : View(context) {
    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)
        // 객체 선언
        val paint = Paint()
        // 메서드 수정
        paint.color = Color.BLACK
        paint.textSize = 100f
        // canvas에 직접 그리기
        canvas?.drawText("존나 졸려 ㅁㅊ", 100f, 100f, paint)

        val blue = Paint()
        blue.color = Color.BLUE
        blue.style = Paint.Style.FILL
        canvas?.drawCircle(150f, 300f, 100f, blue)

        val red = Paint()
        red.color = Color.RED
        red.style = Paint.Style.STROKE
        canvas?.drawCircle(400f, 300f, 100f, red)

        val green = Paint()
        green.color = Color.GREEN
        green.strokeWidth = 20f
        green.style = Paint.Style.STROKE
        val rect = Rect(50, 450, 250, 650)
        canvas?.drawRect(rect, green)

        val cyan = Paint()
        cyan.color = Color.CYAN
        cyan.style = Paint.Style.FILL
        val rectF = RectF(300f, 450f, 500f, 650f)
        canvas?.drawRoundRect(rectF, 30f, 30f, cyan)
    }
}

activity_main.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=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="44dp"
        android:layout_marginBottom="1dp"
        android:text="Draw Text"
        app:layout_constraintBottom_toTopOf="@+id/frameLayout"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <FrameLayout
        android:id="@+id/frameLayout"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="1dp"
        android:layout_marginEnd="1dp"
        android:layout_marginBottom="1dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView">

    </FrameLayout>

</androidx.constraintlayout.widget.ConstraintLayout>