버튼 사용자정의 사용

* 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">

    <com.example.view.MyButton
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="확인"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

* MyButton.java

public class MyButton extends AppCompatButton {

    public MyButton(Context context) {
        super(context);

        init(context);
    }

    public MyButton(Context context, AttributeSet attrs) {
        super(context, attrs);

        init(context);
    }

    public void init(Context context) {
        setBackgroundColor(Color.CYAN);
        setTextColor(Color.BLACK);

        float textSize = getResources().getDimension(R.dimen.text_size); // pixel이 기본값이라 sp로 변환
        setTextSize(textSize);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        Log.d("MyButton", "onDraw 호출됨");
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        Log.d("MyButton", "onTouchEvent 호출됨");

        int action = event.getAction();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                setBackgroundColor(Color.BLUE);
                setTextColor(Color.RED);
                break;
            case MotionEvent.ACTION_OUTSIDE:
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_UP:
                setBackgroundColor(Color.CYAN);
                setTextSize(Color.BLACK);
                break;
        }

        invalidate();

        return true;
    }

}

* dimens.xml(res > values)

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="text_size">30sp</dimen>
</resources>