话不多说，直接上代码
package com.cybeye.module.xingzuo.view;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.os.Build;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import com.cybeye.android.R;
import com.cybeye.module.xingzuo.listener.LoopScrollListener;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
public class LoopView extends View {
private static final String TAG = LoopView.class.getSimpleName();
public static final int MSG_INVALIDATE = 1000;
public static final int MSG_SCROLL_LOOP = 2000;
public static final int MSG_SELECTED_ITEM = 3000;
private ScheduledExecutorService mExecutor = Executors.newSingleThreadScheduledExecutor();
private ScheduledFuture<?> mScheduledFuture;
private int mTotalScrollY;
private LoopScrollListener mLoopListener;
private GestureDetector mGestureDetector;
private int mSelectedItem;
private GestureDetector.SimpleOnGestureListener mOnGestureListener;
private Context mContext;
private Paint mTopBottomTextPaint; //paint that draw top and bottom text
private Paint mCenterTextPaint; // paint that draw center text
private Paint mCenterLinePaint; // paint that draw line besides center text
private ArrayList mDataList;
private int mTextSize;
private int mMaxTextWidth;
private int mMaxTextHeight;
private int mTopBottomTextColor;
private int mCenterTextColor;
private int mCenterLineColor;
private float lineSpacingMultiplier;
private boolean mCanLoop;
private int mTopLineY;
private int mBottomLineY;
private int mCurrentIndex;
private int mInitPosition;
private int mPaddingLeftRight;
private int mPaddingTopBottom;
private float mItemHeight;
private int mDrawItemsCount;
private int mCircularDiameter;
private int mWidgetHeight;
private int mCircularRadius;
private int mWidgetWidth;
public Handler mHandler = new Handler(new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
if (msg.what == MSG_INVALIDATE)
invalidate();
if (msg.what == MSG_SCROLL_LOOP)
startSmoothScrollTo();
else if (msg.what == MSG_SELECTED_ITEM)
itemSelected();
return false;
}
});
public LoopView(Context context) {
this(context, null);
}
public LoopView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public LoopView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initView(context,attrs);
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public LoopView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
initView(context,attrs);
}
private void initView(Context context, AttributeSet attrs) {
TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.LoopView);
if (array != null) {
mTopBottomTextColor = array.getColor(R.styleable.LoopView_topBottomTextColor, 0xffafafaf);
mCenterTextColor = array.getColor(R.styleable.LoopView_centerTextColor, 0xff313131);
mCenterLineColor = array.getColor(R.styleable.LoopView_lineColor, 0xffc5c5c5);
mCanLoop = array.getBoolean(R.styleable.LoopView_canLoop, true);
mInitPosition = array.getInt(R.styleable.LoopView_initPosition, -1);
mTextSize = array.getDimensionPixelSize(R.styleable.LoopView_textsize, sp2px(context, 16));
mDrawItemsCount = array.getInt(R.styleable.LoopView_drawItemCount, 7);
array.recycle();
}
lineSpacingMultiplier = 2.0F;
this.mContext = context;
mOnGestureListener = new LoopViewGestureListener();
mTopBottomTextPaint = new Paint();
mCenterTextPaint = new Paint();
mCenterLinePaint = new Paint();
if (android.os.Build.VERSION.SDK_INT >= 11) {
setLayerType(LAYER_TYPE_SOFTWARE, null);
}
mGestureDetector = new GestureDetector(context, mOnGestureListener);
mGestureDetector.setIsLongpressEnabled(false);
}
private void initData() {
if (mDataList == null) {
throw new IllegalArgumentException("data list must not be null!");
}
mTopBottomTextPaint.setColor(mTopBottomTextColor);
mTopBottomTextPaint.setAntiAlias(true);
mTopBottomTextPaint.setTypeface(Typeface.MONOSPACE);
mTopBottomTextPaint.setTextSize(mTextSize);
mCenterTextPaint.setColor(mCenterTextColor);
mCenterTextPaint.setAntiAlias(true);
mCenterTextPaint.setTextScaleX(1.05F);
mCenterTextPaint.setTypeface(Typeface.MONOSPACE);
mCenterTextPaint.setTextSize(mTextSize);
mCenterLinePaint.setColor(mCenterLineColor);
mCenterLinePaint.setAntiAlias(true);
mCenterLinePaint.setTypeface(Typeface.MONOSPACE);
mCenterLinePaint.setTextSize(mTextSize);
measureTextWidthHeight();
//计算半圆周 -- mMaxTextHeight * lineSpacingMultiplier 表示每个item的高度 mDrawItemsCount = 7
//实际显示5个,留两个是在圆周的上下面
//lineSpacingMultiplier是指text上下的距离的值和maxTextHeight一样的意思 所以 = 2
//mDrawItemsCount - 1 代表圆周的上下两面各被剪切了一半 相当于高度少了一个 mMaxTextHeight
int mHalfCircumference = (int) (mMaxTextHeight * lineSpacingMultiplier * (mDrawItemsCount - 1));
//the diameter of circular 2πr = cir, 2r = height
mCircularDiameter = (int) ((mHalfCircumference * 2) / Math.PI);
//the radius of circular
mCircularRadius = (int) (mHalfCircumference / Math.PI);
// FIXME: 7/8/16 通过控件的高度来计算圆弧的周长
if (mInitPosition == -1) {
if (mCanLoop) {
mInitPosition = (mDataList.size() + 1) / 2;
} else {
mInitPosition = 0;
}
}
mCurrentIndex = mInitPosition;
invalidate();
}
private void measureTextWidthHeight() {
Rect rect = new Rect();
for (int i = 0; i < mDataList.size(); i++) {
String s1 = (String) mDataList.get(i);
mCenterTextPaint.getTextBounds(s1, 0, s1.length(), rect);
int textWidth = rect.width();
if (textWidth > mMaxTextWidth) {
mMaxTextWidth = textWidth;
}
int textHeight = rect.height();
if (textHeight > mMaxTextHeight) {
mMaxTextHeight = textHeight;
}
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mWidgetWidth = getMeasuredWidth();
mWidgetHeight = MeasureSpec.getSize(heightMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
Log.i(TAG, "onMeasure -> heightMode:" + heightMode);
mItemHeight = lineSpacingMultiplier * mMaxTextHeight;
//auto calculate the text's left/right value when draw
mPaddingLeftRight = (mWidgetWidth - mMaxTextWidth) / 2;
mPaddingTopBottom = (mWidgetHeight - mCircularDiameter) / 2;
//topLineY = diameter/2 - itemHeight(mItemHeight)/2 + mPaddingTopBottom
mTopLineY = (int) ((mCircularDiameter - mItemHeight) / 2.0F) + mPaddingTopBottom;
mBottomLineY = (int) ((mCircularDiameter + mItemHeight) / 2.0F) + mPaddingTopBottom;
}
@Override
protected void onDraw(Canvas canvas) {
if (mDataList == null) {
super.onDraw(canvas);
return;
}
super.onDraw(canvas);
//the length of single item is mItemHeight
int mChangingItem = (int) (mTotalScrollY / (mItemHeight));
mCurrentIndex = mInitPosition + mChangingItem % mDataList.size();
if (!mCanLoop) { // can loop
if (mCurrentIndex < 0) {
mCurrentIndex = 0;
}
if (mCurrentIndex > mDataList.size() - 1) {
mCurrentIndex = mDataList.size() - 1;
}
} else { //can not loop
if (mCurrentIndex < 0) {
mCurrentIndex = mDataList.size() + mCurrentIndex;
}
if (mCurrentIndex > mDataList.size() - 1) {
mCurrentIndex = mCurrentIndex - mDataList.size();
}
}
int count = 0;
String itemCount[] = new String[mDrawItemsCount];
//reconfirm each item's value from dataList according to currentIndex,
while (count < mDrawItemsCount) {
int templateItem = mCurrentIndex - (mDrawItemsCount / 2 - count);
if (mCanLoop) {
if (templateItem < 0) {
templateItem = templateItem + mDataList.size();
}
if (templateItem > mDataList.size() - 1) {
templateItem = templateItem - mDataList.size();
}
itemCount[count] = (String) mDataList.get(templateItem);
} else if (templateItem < 0) {
itemCount[count] = "";
} else if (templateItem > mDataList.size() - 1) {
itemCount[count] = "";
} else {
itemCount[count] = (String) mDataList.get(templateItem);
}
count++;
}
//draw top and bottom line
canvas.drawLine(0.0F, mTopLineY, mWidgetWidth, mTopLineY, mCenterLinePaint);
canvas.drawLine(0.0F, mBottomLineY, mWidgetWidth, mBottomLineY, mCenterLinePaint);
count = 0;
int changingLeftY = (int) (mTotalScrollY % (mItemHeight));
while (count < mDrawItemsCount) {
canvas.save();
// L= å * r -> å = rad
float itemHeight = mMaxTextHeight * lineSpacingMultiplier;
//get radian L = (itemHeight * count - changingLeftY),r = mCircularRadius
double radian = (itemHeight * count - changingLeftY) / mCircularRadius;
// a = rad * 180 / π
//get angle
float angle = (float) (radian * 180 / Math.PI);
//when angle >= 180 || angle <= 0 don't draw
if (angle >= 180F || angle <= 0F) {
canvas.restore();
} else {
// translateY = r - r*cos(å) -
//(Math.sin(radian) * mMaxTextHeight) / 2 this is text offset
int translateY = (int) (mCircularRadius - Math.cos(radian) * mCircularRadius - (Math.sin(radian) * mMaxTextHeight) / 2) + mPaddingTopBottom;
canvas.translate(0.0F, translateY);
//scale offset = Math.sin(radian) -> 0 - 1
canvas.scale(1.0F, (float) Math.sin(radian));
if (translateY <= mTopLineY) {
//draw text y between 0 -> mTopLineY,include incomplete text
canvas.save();
canvas.clipRect(0, 0, mWidgetWidth, mTopLineY - translateY);
canvas.drawText(itemCount[count], mPaddingLeftRight, mMaxTextHeight, mTopBottomTextPaint);
canvas.restore();
canvas.save();
canvas.clipRect(0, mTopLineY - translateY, mWidgetWidth, (int) (itemHeight));
canvas.drawText(itemCount[count], mPaddingLeftRight, mMaxTextHeight, mCenterTextPaint);
canvas.restore();
} else if (mMaxTextHeight + translateY >= mBottomLineY) {
//draw text y between mTopLineY -> mBottomLineY ,include incomplete text
canvas.save();
canvas.clipRect(0, 0, mWidgetWidth, mBottomLineY - translateY);
canvas.drawText(itemCount[count], mPaddingLeftRight, mMaxTextHeight, mCenterTextPaint);
canvas.restore();
canvas.save();
canvas.clipRect(0, mBottomLineY - translateY, mWidgetWidth, (int) (itemHeight));
canvas.drawText(itemCount[count], mPaddingLeftRight, mMaxTextHeight, mTopBottomTextPaint);
canvas.restore();
} else if (translateY >= mTopLineY && mMaxTextHeight + translateY <= mBottomLineY) {
//draw center complete text
canvas.clipRect(0, 0, mWidgetWidth, (int) (itemHeight));
canvas.drawText(itemCount[count], mPaddingLeftRight, mMaxTextHeight, mCenterTextPaint);
//center one indicate selected item
mSelectedItem = mDataList.indexOf(itemCount[count]);
}
canvas.restore();
}
count++;
}
}
@Override
public boolean onTouchEvent(MotionEvent motionevent) {
switch (motionevent.getAction()) {
case MotionEvent.ACTION_UP:
default:
if (!mGestureDetector.onTouchEvent(motionevent)) {
startSmoothScrollTo();
}
}
return true;
}
public final void setCanLoop(boolean canLoop) {
mCanLoop = canLoop;
invalidate();
}
/**
* set text size
*
* @param size size indicate sp,not px
*/
public final void setTextSize(float size) {
if (size > 0) {
mTextSize = sp2px(mContext, size);
}
}
public void setInitPosition(int initPosition) {
this.mInitPosition = initPosition;
invalidate();
}
public void setLoopListener(LoopScrollListener LoopListener) {
mLoopListener = LoopListener;
}
/**
* All public method must be called before this method
* @param list data list
*/
public final void setDataList(List<String> list) {
this.mDataList = (ArrayList) list;
initData();
}
public int getSelectedItem() {
return mSelectedItem;
}
private void itemSelected() {
if (mLoopListener != null) {
postDelayed(new SelectedRunnable(), 1000L);
}
}
private void cancelSchedule() {
if (mScheduledFuture != null && !mScheduledFuture.isCancelled()) {
mScheduledFuture.cancel(true);
mScheduledFuture = null;
}
}
private void startSmoothScrollTo() {
int offset = (int) (mTotalScrollY % (mItemHeight));
cancelSchedule();
mScheduledFuture = mExecutor.scheduleWithFixedDelay(new HalfHeightRunnable(offset), 0, 10, TimeUnit.MILLISECONDS);
}
private void startSmoothScrollTo(float velocityY) {
cancelSchedule();
int velocityFling = 20;
mScheduledFuture = mExecutor.scheduleWithFixedDelay(new FlingRunnable(velocityY), 0, velocityFling, TimeUnit.MILLISECONDS);
}
class LoopViewGestureListener extends android.view.GestureDetector.SimpleOnGestureListener {
@Override
public final boolean onDown(MotionEvent motionevent) {
cancelSchedule();
Log.i(TAG, "LoopViewGestureListener->onDown");
return true;
}
@Override
public final boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
startSmoothScrollTo(velocityY);
Log.i(TAG, "LoopViewGestureListener->onFling");
return true;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
Log.i(TAG, "LoopViewGestureListener->onScroll");
mTotalScrollY = (int) ((float) mTotalScrollY + distanceY);
if (!mCanLoop) {
int initPositionCircleLength = (int) (mInitPosition * (mItemHeight));
int initPositionStartY = -1 * initPositionCircleLength;
if (mTotalScrollY < initPositionStartY) {
mTotalScrollY = initPositionStartY;
}
int circleLength = (int) ((float) (mDataList.size() - 1 - mInitPosition) * (mItemHeight));
if (mTotalScrollY >= circleLength) {
mTotalScrollY = circleLength;
}
}
invalidate();
return true;
}
}
public int sp2px(Context context, float spValue) {
final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
return (int) (spValue * fontScale + 0.5f);
}
class SelectedRunnable implements Runnable {
@Override
public final void run() {
LoopScrollListener listener = LoopView.this.mLoopListener;
int selectedItem = getSelectedItem();
mDataList.get(selectedItem);
listener.onItemSelect(selectedItem);
}
}
/**
* Use in ACTION_UP
*/
class HalfHeightRunnable implements Runnable {
int realTotalOffset;
int realOffset;
int offset;
public HalfHeightRunnable(int offset) {
this.offset = offset;
realTotalOffset = Integer.MAX_VALUE;
realOffset = 0;
}
@Override
public void run() {
//first in
if (realTotalOffset == Integer.MAX_VALUE) {
if ((float) offset > mItemHeight / 2.0F) {
//move to next item
realTotalOffset = (int) (mItemHeight - (float) offset);
} else {
//move to pre item
realTotalOffset = -offset;
}
}
realOffset = (int) ((float) realTotalOffset * 0.1F);
if (realOffset == 0) {
if (realTotalOffset < 0) {
realOffset = -1;
} else {
realOffset = 1;
}
}
if (Math.abs(realTotalOffset) <= 0) {
cancelSchedule();
mHandler.sendEmptyMessage(MSG_SELECTED_ITEM);
return;
} else {
mTotalScrollY = mTotalScrollY + realOffset;
mHandler.sendEmptyMessage(MSG_INVALIDATE);
realTotalOffset = realTotalOffset - realOffset;
return;
}
}
}
/**
* Use in {@link LoopViewGestureListener#onFling(MotionEvent, MotionEvent, float, float)}
*/
class FlingRunnable implements Runnable {
float velocity;
final float velocityY;
FlingRunnable(float velocityY) {
this.velocityY = velocityY;
velocity = Integer.MAX_VALUE;
}
@Override
public void run() {
if (velocity == Integer.MAX_VALUE) {
if (Math.abs(velocityY) > 2000F) {
if (velocityY > 0.0F) {
velocity = 2000F;
} else {
velocity = -2000F;
}
} else {
velocity = velocityY;
}
}
Log.i(TAG, "velocity->" + velocity);
if (Math.abs(velocity) >= 0.0F && Math.abs(velocity) <= 20F) {
cancelSchedule();
mHandler.sendEmptyMessage(MSG_SCROLL_LOOP);
return;
}
int i = (int) ((velocity * 10F) / 1000F);
mTotalScrollY = mTotalScrollY - i;
if (!mCanLoop) {
float itemHeight = lineSpacingMultiplier * mMaxTextHeight;
if (mTotalScrollY <= (int) ((float) (-mInitPosition) * itemHeight)) {
velocity = 40F;
mTotalScrollY = (int) ((float) (-mInitPosition) * itemHeight);
} else if (mTotalScrollY >= (int) ((float) (mDataList.size() - 1 - mInitPosition) * itemHeight)) {
mTotalScrollY = (int) ((float) (mDataList.size() - 1 - mInitPosition) * itemHeight);
velocity = -40F;
}
}
if (velocity < 0.0F) {
velocity = velocity + 20F;
} else {
velocity = velocity - 20F;
}
mHandler.sendEmptyMessage(MSG_INVALIDATE);
}
}
}
用法
布局文件
<com.cybeye.module.xingzuo.view.LoopView
android:id="@+id/day_loop_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
app:canLoop="true"
app:centerTextColor="#ff000000" />
Java代码
初始化数据
private void initDataPicker() {
for (int j = 0; j < 12; j++) {
if (isChainese) {
monthList.add(StringUtil.format2LenStr(j + 1) + getString(R.string.month));
} else {
monthList.add(StringUtil.monthString[j]);
}
}
monthView.setDataList((ArrayList) monthList);
monthView.setInitPosition(monthPos);
initDayPickerView();
}
private void initDayPickerView() {
int dayMaxInMonth;
Calendar calendar = Calendar.getInstance();
dayList = new ArrayList<String>();
// calendar.set(Calendar.YEAR, minYear + yearPos);
calendar.set(Calendar.MONTH, monthPos);
//get max day in month
dayMaxInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
for (int i = 0; i < dayMaxInMonth; i++) {
String day = StringUtil.format2LenStr(i + 1);
if (isChainese) {
day = day + getString(R.string.m_day);
}
dayList.add(day);
}
dayView.setDataList((ArrayList) dayList);
dayView.setInitPosition(dayPos);
}
监听事件
monthView.setLoopListener(new LoopScrollListener() {
@Override
public void onItemSelect(int item) {
monthPos = item;
initDayPickerView();
int position = DateUtil.getConstellationPosition(item + 1, StringUtil.format2LenStr(dayPos + 1));
CLog.e("====月======", "" + (item + 1) + "==" + (dayPos + 1) + "=====" + position);
setConstellationData(position);
}
});
dayView.setLoopListener(new LoopScrollListener() {
@Override
public void onItemSelect(int item) {
dayPos = item;
int position = DateUtil.getConstellationPosition(monthPos + 1, StringUtil.format2LenStr(item + 1));
CLog.e("====日======", "" + (monthPos + 1) + "==" + (item + 1) + "=====" + position);
setConstellationData(position);
}
});