backgroundのDrawableの分だけサイズを確保するView

雑にdivider引くときめんどくさかったので。

CustomView.java

public class CustomView extends View {

    public CustomView(Context context) {
        this(context, null);
    }

    public CustomView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CustomView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Drawable background = getBackground();
        int width = background != null ? background.getIntrinsicWidth() : 0;
        int height = background != null ? background.getIntrinsicHeight() : 0;

        setMeasuredDimension(
                View.resolveSize(width, widthMeasureSpec),
                View.resolveSize(height, heightMeasureSpec));
    }
}