Android自定义时间选择器或者WheelView

public class PickView extends View{
    public static final String TAG = "PickerView";
    /**
     * text之间间距和minTextSize之比
     */
    public static final float MARGIN_ALPHA = 2.8f;
    /**
     * 自动回滚到中间的速度
     */
    public static final float SPEED = 2;

    private List mDataList;
    /**
     * 选中的位置，这个位置是mDataList的中心位置，一直不变
     */
    private int mCurrentSelected;
    private Paint mPaint;
    private Paint mPaint2;

    private float mMaxTextSize = 20;
    private float mMinTextSize = 18;

    private float mMaxTextAlpha = 255;
    private float mMinTextAlpha = 120;

//    private int mColorText = 0x03ab40;
//    private int mColorText2 = 0x000000;


    private int mColorText = 0xe7e4e6;
    private int mColorText2 = 0xd2c2c3;

    private int mViewHeight;
    private int mViewWidth;

    private float mLastDownY;
    /**
     * 滑动的距离
     */
    private float mMoveLen = 0;
    private boolean isInit = false;
    private onSelectListener mSelectListener;
    private Timer timer;
    private MyTimerTask mTask;


    Handler updateHandler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            if (Math.abs(mMoveLen) < SPEED) {
                mMoveLen = 0;
                if (mTask != null) {
                    mTask.cancel();
                    mTask = null;
                    performSelect();
                }
            } else
                // 这里mMoveLen / Math.abs(mMoveLen)是为了保有mMoveLen的正负号，以实现上滚或下滚
                mMoveLen = mMoveLen - mMoveLen / Math.abs(mMoveLen) * SPEED;
            invalidate();
        }

    };

    public PickView(Context context) {
        super(context);
        init();
    }

    public PickView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public void setOnSelectListener(onSelectListener listener) {
        mSelectListener = listener;
    }

    private void performSelect() {
        if (mSelectListener != null)
            mSelectListener.onSelect(mDataList.get(mCurrentSelected));
    }

    public void setData(List datas) {
        mDataList = datas;
//        if(mCurrentSelected!=0){
//
//        }
//        mCurrentSelected = datas.size() / 2;
        invalidate();
    }

    public void setSelected(int selected) {
        mCurrentSelected = selected;
    }

    private void moveHeadToTail() {
        String head = mDataList.get(0);
        mDataList.remove(0);
        mDataList.add(head);
    }

    private void moveTailToHead() {
        String tail = mDataList.get(mDataList.size() - 1);
        mDataList.remove(mDataList.size() - 1);
        mDataList.add(0, tail);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mViewHeight = getMeasuredHeight();
        mViewWidth = getMeasuredWidth();
        // 按照View的高度计算字体大小
        mMaxTextSize = mViewHeight / 4.0f;
        mMinTextSize = mMaxTextSize / 2f;
        isInit = true;
        invalidate();
    }

    private void init() {
        timer = new Timer();
        mDataList = new ArrayList();
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setTextAlign(Paint.Align.CENTER);
        mPaint.setColor(mColorText);

        mPaint2 = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint2.setStyle(Paint.Style.FILL);
        mPaint2.setTextAlign(Paint.Align.CENTER);
        mPaint2.setColor(mColorText2);


    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 根据index绘制view
        if (isInit)
            drawData(canvas);
    }

    private void drawData(Canvas canvas) {
        // 先绘制选中的text再往上往下绘制其余的text
        float scale = parabola(mViewHeight / 4.0f, mMoveLen);
        float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize;
        //Log.d("maxsize",size+"================");
        mPaint.setTextSize(45);
        mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha));
        // text居中绘制，注意baseline的计算才能达到居中，y值是text中心坐标
        float x = (float) (mViewWidth / 2.0);
        float y = (float) (mViewHeight / 2.0 + mMoveLen);
        Paint.FontMetricsInt fmi = mPaint.getFontMetricsInt();
        float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0));

        canvas.drawText(mDataList.get(mCurrentSelected), x, baseline, mPaint);
        // 绘制上方data
        for (int i = 1; (mCurrentSelected - i) >= 0; i++) {
            drawOtherText(canvas, i, -1);
        }
        // 绘制下方data
        for (int i = 1; (mCurrentSelected + i) < mDataList.size(); i++) {
            drawOtherText(canvas, i, 1);
        }

    }

    /**
     * @param canvas
     * @param position 距离mCurrentSelected的差值
     * @param type     1表示向下绘制，-1表示向上绘制
     */
    private void drawOtherText(Canvas canvas, int position, int type) {
        float d = (float) (MARGIN_ALPHA * mMinTextSize + type
                * mMoveLen);
        float scale = parabola(mViewHeight / 4.0f, d);
        float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize;
        // Log.d("msize",size+"================");
        mPaint2.setTextSize(35);
        mPaint2.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha));
        float y = (float) (mViewHeight / 2.0 + type * d);
        Paint.FontMetricsInt fmi = mPaint2.getFontMetricsInt();
        float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0));
        canvas.drawText(mDataList.get(mCurrentSelected + type),
                (float) (mViewWidth / 2.0), baseline, mPaint2);


    }

    /**
     * 抛物线
     *
     * @param zero 零点坐标
     * @param x    偏移量
     * @return scale
     */
    private float parabola(float zero, float x) {
        float f = (float) (1 - Math.pow(x / zero, 2));
        return f < 0 ? 0 : f;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_DOWN:
                doDown(event);
                break;
            case MotionEvent.ACTION_MOVE:
                doMove(event);
                break;
            case MotionEvent.ACTION_UP:
                doUp(event);
                break;
        }
        return true;
    }

    private void doDown(MotionEvent event) {
        if (mTask != null) {
            mTask.cancel();
            mTask = null;
        }
        mLastDownY = event.getY();
    }

    private void doMove(MotionEvent event) {

        mMoveLen += (event.getY() - mLastDownY);

        if (mMoveLen > MARGIN_ALPHA * mMinTextSize / 2) {
            // 往下滑超过离开距离
            moveTailToHead();
            mMoveLen = mMoveLen - MARGIN_ALPHA * mMinTextSize;
        } else if (mMoveLen < -MARGIN_ALPHA * mMinTextSize / 2) {
            // 往上滑超过离开距离
            moveHeadToTail();
            mMoveLen = mMoveLen + MARGIN_ALPHA * mMinTextSize;
        }

        mLastDownY = event.getY();
        invalidate();
    }

    private void doUp(MotionEvent event) {
        // 抬起手后mCurrentSelected的位置由当前位置move到中间选中位置
        if (Math.abs(mMoveLen) < 0.0001) {
            mMoveLen = 0;
            return;
        }
        if (mTask != null) {
            mTask.cancel();
            mTask = null;
        }
        mTask = new MyTimerTask(updateHandler);
        timer.schedule(mTask, 0, 10);
    }

    class MyTimerTask extends TimerTask {
        Handler handler;

        public MyTimerTask(Handler handler) {
            this.handler = handler;
        }

        @Override
        public void run() {
            handler.sendMessage(handler.obtainMessage());
        }

    }

    public interface onSelectListener {
        void onSelect(String text);
    }

}

自定义view的使用：

xml:

   <LinearLayout
            app:layout_heightPercent="81%h"
            app:layout_widthPercent="48.1%w"
            android:orientation="horizontal"
            android:layout_centerInParent="true"
            android:layout_width="0dp"
            android:layout_height="0dp">
            <com.yosemite.myview.PickView
                android:layout_alignParentLeft="true"
                android:id="@+id/pickview_hour"
                android:layout_width="0dp"
android:layout_weight="1"
                android:layout_height="match_parent" />
            <com.yosemite.myview.PickView
                android:layout_alignParentRight="true"
                android:id="@+id/pickview_minute"
                android:layout_weight="1"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                />

        LinearLayout>

代码中：

pickview_hour= (PickView) findViewById(R.id.pickview_hour);
pickview_minute= (PickView) findViewById(R.id.pickview_minute);
pickview_minute.setSelected(30);
List hours=new ArrayList(); List minutes=new ArrayList();

for (int i = 0; i < 24; i++)
{
    hours.add(i < 10 ? "0" + i : "" + i);
}
for (int i = 0; i < 60; i++)
{
    minutes.add(i < 10 ? "0" + i : "" + i);
}
pickview_hour.setData(hours);
pickview_hour.setSelected(12);
pickview_minute.setData(minutes);
pickview_minute.setOnSelectListener(new PickView.onSelectListener() {
    @Override
    public void onSelect(String text) {

    }
});