地区选择器PickerScrollView

自定义

//创建一个类

@SuppressLint({"HandlerLeak","ClickableViewAccessibility" })

public class PickerScrollView  extends View {

public static final StringTAG ="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 ListmDataList;

/**

    * 选中的位置,这个位置是mDataList的中心位置,一直不变

    */

    private int mCurrentSelected;

private PaintmPaint;

private float mMaxTextSize =20;

private float mMinTextSize =10;

private float mMaxTextAlpha =255;

private float mMinTextAlpha =120;

private int mColorText =0x333333;

private int mViewHeight;

private int mViewWidth;

private float mLastDownY;

/**

    * 滑动的距离

    */

    private float mMoveLen =0;

private boolean isInit =false;

private onSelectListenermSelectListener;

private Timertimer;

private MyTimerTaskmTask;

HandlerupdateHandler =new Handler() {

@Override

        public void handleMessage(Message msg) {

if (Math.abs(mMoveLen)

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 PickerScrollView(Context context) {

super(context);

init();

}

public PickerScrollView(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;

mCurrentSelected = datas.size() /2;

invalidate();

}

/**

    * 选择选中的item的index

*

    * @param selected

    */

    public void setSelected(int selected) {

mCurrentSelected = selected;

int distance =mDataList.size() /2 -mCurrentSelected;

if (distance <0)

for (int i =0; i < -distance; i++) {

moveHeadToTail();

mCurrentSelected--;

}

else if (distance >0)

for (int i =0; i < distance; i++) {

moveTailToHead();

mCurrentSelected++;

}

invalidate();

}

/**

    * 选择选中的内容

    *

    * @param mSelectItem

    */

    public void setSelected(String mSelectItem) {

for (int i =0; i

if (mDataList.get(i).equals(mSelectItem)) {

setSelected(i);

break;

}

}

private void moveHeadToTail() {

Pickers head =mDataList.get(0);

mDataList.remove(0);

mDataList.add(head);

}

private void moveTailToHead() {

Pickers 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 /8.0f;

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);

}

@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;

mPaint.setTextSize(size);

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));

int indexs =mCurrentSelected;

String textData =mDataList.get(indexs).getShowConetnt();

canvas.drawText(textData, 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)

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 * position + type

*mMoveLen);

float scale = parabola(mViewHeight /4.0f, d);

float size = (mMaxTextSize -mMinTextSize) * scale +mMinTextSize;

mPaint.setTextSize(size);

mPaint.setAlpha((int) ((mMaxTextAlpha -mMinTextAlpha) * scale +mMinTextAlpha));

float y = (float) (mViewHeight /2.0 + type * d);

Paint.FontMetricsInt fmi =mPaint.getFontMetricsInt();

float baseline = (float) (y - (fmi.bottom /2.0 + fmi.top /2.0));

int indexs =mCurrentSelected + type * position;

String textData =mDataList.get(indexs).getShowConetnt();

canvas.drawText(textData, (float) (mViewWidth /2.0), baseline,mPaint);

}

/**

    * 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 MyTimerTaskextends TimerTask {

Handlerhandler;

public MyTimerTask(Handler handler) {

this.handler = handler;

}

@Override

        public void run() {

handler.sendMessage(handler.obtainMessage());

}

}

public interface onSelectListener {

void onSelect(Pickers pickers);

}

}


//xml布局控件使用

    android:layout_marginTop="20dp"

    android:id="@+id/pic"

    android:layout_width="match_parent"

    android:layout_height="200dp" />


private Listlist;// 滚动选择器数据

private String[]id;

private String[]name;

//初始化数据

private void initData() {

list =new ArrayList();

id =new String[]{"1","2","3","4","5","6","7","8","9"};

name =new String[]{"北京市","安阳市","丽江市","天津市","长春市","昆明市","哈尔滨市","葫芦岛","Your Heart"};

for (int i =0; i

list.add(new Pickers(name[i],id[i]));

}

// 设置数据,默认选择第一条

    pic.setData(list);

pic.setSelected(0);

}


public class Pickers   implements Serializable {

private static final long serialVersionUID =1L;

private StringshowConetnt;

private StringshowId;

public String getShowConetnt() {

return showConetnt;

}

public String getShowId() {

return showId;

}

public Pickers(String showConetnt, String showId) {

super();

this.showConetnt = showConetnt;

this.showId = showId;

}

public Pickers() {

super();

}

}


// 滚动选择器选中事件

PickerScrollView.onSelectListenerpickerListener =new PickerScrollView.onSelectListener() {

@Override

    public void onSelect(Pickers pickers) {

String showConetnt = pickers.getShowConetnt();

Log.e("+++++","选择:" + pickers.getShowId() +"--银行:"

                + pickers.getShowConetnt());

often.setText(showConetnt);

}

};

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