VerticalTextView.java

package com.wdullaer.materialdatetimepicker;

import android.content.Context;
import android.graphics.Canvas;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.view.Gravity;
import android.widget.TextView;

/**
 * TextView that renders it's contents vertically. (Just using rotate doesn't work because onMeasure
 * happens before the View is rotated causing incorrect View boundaries)
 * Created by wdullaer on 28/03/16.
 */
public class VerticalTextView extends TextView {
    final boolean topDown;

    public VerticalTextView(Context context, AttributeSet attrs){
        super(context, attrs);
        final int gravity = getGravity();
        if (Gravity.isVertical(gravity) && (gravity&Gravity.VERTICAL_GRAVITY_MASK) == Gravity.BOTTOM) {
            setGravity((gravity&Gravity.HORIZONTAL_GRAVITY_MASK) | Gravity.TOP);
            topDown = false;
        } else {
            topDown = true;
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
        super.onMeasure(heightMeasureSpec, widthMeasureSpec);
        setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
    }

    @Override
    protected void onDraw(Canvas canvas){
        TextPaint textPaint = getPaint();
        textPaint.setColor(getCurrentTextColor());
        textPaint.drawableState = getDrawableState();

        canvas.save();

        if (topDown){
            canvas.translate(getWidth(), 0);
            canvas.rotate(90);
        } else {
            canvas.translate(0, getHeight());
            canvas.rotate(-90);
        }


        canvas.translate(getCompoundPaddingLeft(), getExtendedPaddingTop());

        getLayout().draw(canvas);
        canvas.restore();
    }
}