안드로메트릭 IOS 날짜 또는 시간 선택기 WheelPicker

심사하는 형제~, 문장의 구조와 효과를 보여주면 난 아직 쓸 줄 몰라.
프로젝트에서 IOS를 모방한 시간 날짜 선택기를 사용했어요. 응, 바로 그런 롤러 효과예요. 더 말할 것도 없고 효과부터 봐요!
블로그를 쓸 줄 모르는구나, 움짤을 만들 줄 모른다는 뜻이다.이 그림을 보면 알 수 있을 텐데, 바로 이 효과다.
아, 먼저 설명해 드릴게요. 이것은 다른 사람의 코드를 참고하여 이루어진 것입니다. 비록 변경이 있었지만 저도 오리지널은 말하지 않겠습니다. 그냥 전재로 하겠습니다.
이어서 코드를 올려라!

import java.util.ArrayList;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class WheelPicker extends View {

    private Context mContext;

    private int mViewHeight;
    private int mViewWidth;

    /**         */
    private int mCenterItemHeight;

    private int mCenterY;

    private float mLastDownY;  //       
    private float mMoveDistanceY = 0;
    /**        */
    private int mCurrentDataIndex = 0;
    /**        */
    private Paint mTextPaint;
    /**        */
    private Paint mLinePaint;
    /**        */
    private int mMaxTextSize;
    /**        */
    private float mGapRatio = 0;
    /**        */
    private boolean mIsTouchEnable = true;

    /**        */
    private boolean mIsTouchDownEnable = true;
    /**        */
    private boolean mIsTouchUpEnable = true;

    private ArrayList mDataList = new ArrayList();

    private OnScrollItemIndexListener indexListener;
    
    public void setOnScrollItemIndexListener(OnScrollItemIndexListener indexListener){
    	this.indexListener = indexListener;
    }
    
    public WheelPicker(Context context) {
        super(context);
        init(context);
    }

    public WheelPicker(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }
    
    private void init(Context context){
        this.mContext = context;
        mTextPaint = new Paint();
        mTextPaint.setStyle(Paint.Style.FILL);
        mTextPaint.setTextAlign(Paint.Align.CENTER);
        mTextPaint.setColor(0xff1f1f1f);

        mLinePaint = new Paint();
        mLinePaint.setStyle(Paint.Style.FILL);
        mLinePaint.setTextAlign(Paint.Align.CENTER);
        mLinePaint.setColor(0xff1f1f1f);
    }

    public void setData(ArrayList mDataList, int index){
    	mCurrentDataIndex = index;
    	this.mDataList.clear();
    	this.mDataList.addAll(mDataList);
        invalidate();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        mViewHeight = getMeasuredHeight();
        mViewWidth = getMeasuredWidth();

        mCenterY = mViewHeight/2;
        mMaxTextSize = mViewHeight/10;
        mCenterItemHeight = mViewHeight/4;
        mGapRatio = 0.7f;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if(mIsTouchEnable) {
            switch (event.getActionMasked()) {
                case MotionEvent.ACTION_DOWN:
                    onActionDown(event);
                    break;
                case MotionEvent.ACTION_MOVE:
                    onActionMove(event);
                    break;
                case MotionEvent.ACTION_UP:
                    onActionUp(event);
                    break;
            }
        }
        return true;
    }

    private void onActionDown(MotionEvent event){
        mLastDownY  = event.getY();
        //mMoveDistanceY = 0;
    }

    private void onActionMove(MotionEvent event){
        float currentY = event.getY();
        float diff = currentY - mLastDownY;

        if(mIsTouchUpEnable && mIsTouchDownEnable) {
            mMoveDistanceY += diff;
        }else if(!mIsTouchUpEnable && mIsTouchDownEnable){   //            
            if(diff > 0){
                mMoveDistanceY += diff;
                mIsTouchUpEnable = true;
            }
        }else if(mIsTouchUpEnable && !mIsTouchDownEnable){   //             
            if(diff < 0){
                mMoveDistanceY += diff;
                mIsTouchDownEnable = true;
            }
        }
        mLastDownY = currentY;
        invalidate();
    }

    private void onActionUp(MotionEvent event){
        returnBack(mMoveDistanceY, 0);
    }

    private void drawText(Canvas canvas, int currentIndex, int position){
        float length = mCenterY + mMoveDistanceY;
        if(position == 0){//         
            float scale = getScale((int) mMoveDistanceY);
            mTextPaint.setTextSize((float) (mMaxTextSize * scale));
            mTextPaint.setColor(getAlphaTextColor(scale));
            Paint.FontMetricsInt fontMetricsInt = mTextPaint.getFontMetricsInt();
            int diff = (fontMetricsInt.bottom + fontMetricsInt.top)/2;

            float baseY = length-diff;
            canvas.drawText(mDataList.get(currentIndex), mViewWidth / 2, baseY, mTextPaint);

            if(mMoveDistanceY > mCenterItemHeight/2){            //    index 
                if(mCurrentDataIndex > 0) {
                    mCurrentDataIndex--;
                }else{
                    mIsTouchDownEnable = false;                   //    
                }
                mMoveDistanceY = 0;
            }else if(mMoveDistanceY < -mCenterItemHeight/2){    //    index 
                if(mCurrentDataIndex < mDataList.size()-1) {
                    mCurrentDataIndex++;
                }else{
                    mIsTouchUpEnable = false;                     //    
                }
                mMoveDistanceY = 0;
            }
        }else {                                    //      
            int realIndex = currentIndex + position;

            if(realIndex >= 0 && realIndex < mDataList.size()){
                length = length + mCenterItemHeight * mGapRatio * position;

                float scale = getScale((int) length - mCenterY);
                mTextPaint.setTextSize((float) (mMaxTextSize * scale));
                mTextPaint.setColor(getAlphaTextColor(scale));
                Paint.FontMetricsInt fontMetricsInt = mTextPaint.getFontMetricsInt();
                int diff = (fontMetricsInt.bottom + fontMetricsInt.top)/2;

                canvas.drawText(mDataList.get(realIndex), mViewWidth/2 , length-diff, mTextPaint);
            }
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        for(int i=-3; i<=3; i++){
            drawText(canvas, mCurrentDataIndex, i);
        }
        canvas.drawLine(0, mCenterY-mCenterItemHeight/2, mViewWidth, mCenterY-mCenterItemHeight/2, mLinePaint);
        canvas.drawLine(0, mCenterY + mCenterItemHeight / 2, mViewWidth, mCenterY + mCenterItemHeight / 2, mLinePaint);
    }

    private float getScale(int lengthToCenter){
        float ret = (float) (1 - Math.pow(((float)lengthToCenter)/mCenterY, 2));
        if(ret < 0){
            ret = 0;
        }
        return ret;
    }

    private void returnBack(float start, float end){
        mIsTouchEnable = false;
        ValueAnimator valueAnimator = ValueAnimator.ofFloat(start, end);
        valueAnimator.setDuration(100);
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                mMoveDistanceY = (Float) valueAnimator.getAnimatedValue();
                if (Math.abs(mMoveDistanceY) <= 3) {
                    mMoveDistanceY = 0;
                    mIsTouchEnable = true;
                }
                invalidate();
            }
        });
        valueAnimator.start();
        if(indexListener!=null){
        	indexListener.ScrollItemIndex(this, mCurrentDataIndex);
        }
    }

    /**
     *           
     * @param scale
     * @return
     */
    private int getAlphaTextColor(float scale){
        int data = (int) (255 * scale);
        return (data << 24);
    }
    
    public int getTimeDataIndex(){
        return mCurrentDataIndex;
    }

    public String getTimeData(){
        return mDataList.get(mCurrentDataIndex);
    }
    
    public interface OnScrollItemIndexListener{
    	
    	public void ScrollItemIndex(View view, int index);
    	
    }
    
}

그렇습니다. 설명은 그만두고 심사를 통해 편집을 하겠습니다.
블로그가 어떻게 보이는지 아직 모르겠어요.