相信大家一定都见过iPhone上面的时间滚动轮的效果,类似轮盘一样的滚动来选择数据,非常有意思,动画效果也很生动,相比较安卓自带的spinner,TimePicker等控件,用户体验要好很多。在android上面去实现这样的效果,需要自定义view来实现,下面一个demo,进行了详细的注释,希望对您有所帮助,下面先放上改动之后的效果图片:
由于代码比较多,只贴上了自定义view的相关代码:
- package com.cogent.iPhonewheel.widget;
- import java.util.LinkedList;
- import java.util.List;
- import android.content.Context;
- import android.graphics.Canvas;
- import android.graphics.Paint;
- import android.graphics.Rect;
- import android.graphics.drawable.Drawable;
- import android.graphics.drawable.GradientDrawable;
- import android.graphics.drawable.GradientDrawable.Orientation;
- import android.os.Handler;
- import android.os.Message;
- import android.text.Layout;
- import android.text.StaticLayout;
- import android.text.TextPaint;
- import android.util.AttributeSet;
- import android.util.FloatMath;
- import android.view.GestureDetector;
- import android.view.MotionEvent;
- import android.view.View;
- import android.view.GestureDetector.SimpleOnGestureListener;
- import android.view.animation.Interpolator;
- import android.widget.Scroller;
- import com.cogent.iPhonewheel.Interface.OnWheelChangedListener;
- import com.cogent.iPhonewheel.Interface.OnWheelScrollListener;
- import com.cogent.iPhonewheel.Interface.WheelAdapter;
- import com.cogent.iPhonewheel.UI.R;
- /**
- * 自定义的滚轮view
- *
- * @author Administrator
- *
- */
- public class WheelView extends View {
- /** 滚动持续的时间 */
- private static final int SCROLLING_DURATION = 400;
- /** 最少滚动的位置 */
- private static final int MIN_DELTA_FOR_SCROLLING = 1;
- /** 当前值和标签的颜色 */
- private static final int VALUE_TEXT_COLOR = 0xF0FF6347;
- /** item文字的颜色 */
- private static final int ITEMS_TEXT_COLOR = 0xFF000000;
- /** 顶部和底部阴影的颜色 */
- private static final int[] SHADOWS_COLORS = new int[] { 0xFF111111,
- 0x00AAAAAA, 0x00AAAAAA };
- /** 附加的item的高度 */
- private static final int ADDITIONAL_ITEM_HEIGHT = 15;
- /** 字体大小 */
- private static final int TEXT_SIZE = 30;
- /** 顶部和底部item的偏移值 */
- private static final int ITEM_OFFSET = TEXT_SIZE / 5;
- /** item布局的附加宽度 */
- private static final int ADDITIONAL_ITEMS_SPACE = 10;
- /** 标签偏移值 */
- private static final int LABEL_OFFSET = 8;
- /** 左右padding值 */
- private static final int PADDING = 10;
- /** 默认可见的item数目 */
- private static final int DEF_VISIABLE_ITEMS = 5;
- /** 初始化wheeladpater */
- private WheelAdapter adapter = null;
- /** 当前item位置 */
- private int currentItem = 0;
- /** item宽度 */
- private int itemsWidth = 0;
- /** 标签宽度 */
- private int labelWidth = 0;
- /** 可见item数目 */
- private int visibleItems = DEF_VISIABLE_ITEMS;
- /** item高度 */
- private int itemHeight = 0;
- /** item的字符串属性对象 */
- private TextPaint itemsPaint;
- /** value的字符串属性对象 */
- private TextPaint valuePaint;
- // Layouts
- private StaticLayout itemsLayout, labelLayout, valueLayout;
- private String label;
- private Drawable centerDrawable;
- /** 顶部渐变drawable对象 */
- private GradientDrawable topShadow;
- /** 顶部渐变drawable对象 */
- private GradientDrawable bottomShadow;
- /** 滚动动作是否执行 */
- private boolean isScrollingPerformed;
- /** 滚动偏移量 */
- private int scrollingOffset;
- /** 手势侦测对象 */
- private GestureDetector gestureDetector;
- private Scroller scroller;
- private int lastScrollY;
- /** 是否可循环 */
- private boolean isCyclic = false;
- /** 实例化OnWheelChangedListener */
- private List
changingListeners = new LinkedList (); - /** 实例化OnWheelScrollListener */
- private List
scrollingListeners = new LinkedList (); - /**
- * 3个参数构造函数
- */
- public WheelView(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- initData(context);
- }
- /**
- * 2个参数构造函数
- */
- public WheelView(Context context, AttributeSet attrs) {
- super(context, attrs);
- initData(context);
- }
- /**
- * 1个参数构造函数
- */
- public WheelView(Context context) {
- super(context);
- initData(context);
- }
- private void initData(Context context) {
- gestureDetector = new GestureDetector(context, gestureListener);
- gestureDetector.setIsLongpressEnabled(false);// 设置手势长按不起作用
- scroller = new Scroller(context);
- }
- /**
- * 获取滚轮适配器
- *
- * @return
- */
- public WheelAdapter getAdapter() {
- return adapter;
- }
- /**
- * 设置滚轮适配器
- *
- * @param adapter
- */
- public void setAdapter(WheelAdapter adapter) {
- this.adapter = adapter;
- invalidateLayouts();
- invalidate();// 是视图无效
- }
- /**
- * 设置指定的滚轮动画变化率
- *
- * @param interpolator
- */
- public void setInterpolator(Interpolator interpolator) {
- scroller.forceFinished(true);
- scroller = new Scroller(getContext(), interpolator);
- }
- /**
- * 得到可见item的数目
- *
- * @return the count of visible items
- */
- public int getVisibleItems() {
- return visibleItems;
- }
- /**
- * 设置可见item的数目
- *
- * @param count
- * the new count
- */
- public void setVisibleItems(int count) {
- visibleItems = count;
- invalidate();
- }
- /**
- * 得到标签
- *
- * @return
- */
- public String getLabel() {
- return label;
- }
- /**
- * 设置标签
- *
- * @param newLabel
- */
- public void setLabel(String newLabel) {
- if (label == null || !label.equals(newLabel)) {
- label = newLabel;
- labelLayout = null;
- invalidate();
- }
- }
- /**
- * 增加滚轮变化监听器
- *
- * @param listener
- */
- public void addChangingListener(OnWheelChangedListener listener) {
- changingListeners.add(listener);
- }
- /**
- * 移除滚轮变化监听器
- *
- * @param listener
- */
- public void removeChangingListener(OnWheelChangedListener listener) {
- changingListeners.remove(listener);
- }
- /**
- * 通知改变的监听器
- *
- * @param oldValue
- * @param newValue
- */
- protected void notifyChangingListeners(int oldValue, int newValue) {
- for (OnWheelChangedListener listener : changingListeners) {
- listener.onChanged(this, oldValue, newValue);
- }
- }
- /**
- * 增加滚轮监听器
- *
- * @param listener
- * the listener
- */
- public void addScrollingListener(OnWheelScrollListener listener) {
- scrollingListeners.add(listener);
- }
- /**
- * 移除滚轮监听器
- *
- * @param listener
- * the listener
- */
- public void removeScrollingListener(OnWheelScrollListener listener) {
- scrollingListeners.remove(listener);
- }
- /**
- * 通知监听器开始滚动
- */
- protected void notifyScrollingListenersAboutStart() {
- for (OnWheelScrollListener listener : scrollingListeners) {
- listener.onScrollingStarted(this);
- }
- }
- /**
- * 通知监听器结束滚动
- */
- protected void notifyScrollingListenersAboutEnd() {
- for (OnWheelScrollListener listener : scrollingListeners) {
- listener.onScrollingFinished(this);
- }
- }
- /**
- * 取得当前item
- *
- * @return
- */
- public int getCurrentItem() {
- return currentItem;
- }
- /**
- * 设置当前item
- * @param index
- * @param animated
- */
- public void setCurrentItem(int index, boolean animated) {
- if (adapter == null || adapter.getItemsCount() == 0) {
- return;
- }
- if (index < 0 || index >= adapter.getItemsCount()) {
- if (isCyclic) {
- while (index < 0) {
- index += adapter.getItemsCount();
- }
- index %= adapter.getItemsCount();
- } else {
- return;
- }
- }
- if (index != currentItem) {
- if (animated) {
- scroll(index - currentItem, SCROLLING_DURATION);
- } else {
- invalidateLayouts();
- int old = currentItem;
- currentItem = index;
- notifyChangingListeners(old, currentItem);
- invalidate();
- }
- }
- }
- /**
- * 设置当前item w/o 动画. 当index有误是不做任何响应.
- *
- * @param index
- * the item index
- */
- public void setCurrentItem(int index) {
- setCurrentItem(index, false);
- }
- /**
- * 测试滚轮是否可循环.
- *
- * @return true if wheel is cyclic
- */
- public boolean isCyclic() {
- return isCyclic;
- }
- /**
- * 设置滚轮循环标志
- *
- * @param isCyclic
- * the flag to set
- */
- public void setCyclic(boolean isCyclic) {
- this.isCyclic = isCyclic;
- invalidate();
- invalidateLayouts();
- }
- /**
- * 使布局无效
- */
- private void invalidateLayouts() {
- itemsLayout = null;
- valueLayout = null;
- scrollingOffset = 0;
- }
- /**
- * 初始化资源信息
- */
- private void initResourceIfNecessary() {
- if (itemsPaint == null) {
- itemsPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG
- | Paint.FAKE_BOLD_TEXT_FLAG);
- itemsPaint.setTextSize(TEXT_SIZE);
- }
- if (valuePaint == null) {
- valuePaint = new TextPaint(Paint.ANTI_ALIAS_FLAG
- | Paint.FAKE_BOLD_TEXT_FLAG | Paint.DITHER_FLAG);
- valuePaint.setTextSize(TEXT_SIZE);
- valuePaint.setShadowLayer(0.1f, 0, 0.1f, 0xFFC0C0C0);
- }
- if (centerDrawable == null) {
- centerDrawable = getContext().getResources().getDrawable(
- R.drawable.wheel_val);
- }
- if (topShadow == null) {
- topShadow = new GradientDrawable(Orientation.TOP_BOTTOM,
- SHADOWS_COLORS);
- }
- if (bottomShadow == null) {
- bottomShadow = new GradientDrawable(Orientation.BOTTOM_TOP,
- SHADOWS_COLORS);
- }
- setBackgroundResource(R.drawable.wheel_bg);
- }
- /**
- * 计算layout所需的高度
- * @param layout
- * @return
- */
- private int getDesiredHeight(Layout layout) {
- if (layout == null) {
- return 0;
- }
- int desired = getItemHeight() * visibleItems - ITEM_OFFSET * 2
- - ADDITIONAL_ITEM_HEIGHT;
- desired = Math.max(desired,getSuggestedMinimumHeight());
- return desired;
- }
- /**
- * 通过index得到text
- * @param index
- * @return
- */
- private String getTextItem(int index){
- if(adapter == null || adapter.getItemsCount() == 0){
- return null;
- }
- int count = adapter.getItemsCount();
- if((index < 0 || index >= count) && !isCyclic){
- return null;
- }else{
- while(index < 0){
- index += count;
- }
- }
- index %= count;
- return adapter.getItem(index);
- }
- /**
- * 根据当前值构建text
- *
- * @param useCurrentValue
- * @return the text
- */
- private String buildText(boolean useCurrentValue) {
- StringBuilder itemsText = new StringBuilder();
- int addItems = visibleItems / 2 + 1;
- for (int i = currentItem - addItems; i <= currentItem + addItems; i++) {
- if (useCurrentValue || i != currentItem) {
- String text = getTextItem(i);
- if (text != null) {
- itemsText.append(text);
- }
- }
- if (i < currentItem + addItems) {
- itemsText.append("\n");
- }
- }
- return itemsText.toString();
- }
- /**
- * 返回可以表示的item的***长度
- * @return the max length
- */
- private int getMaxTextLength() {
- WheelAdapter adapter = getAdapter();
- if (adapter == null) {
- return 0;
- }
- int adapterLength = adapter.getMaximumLength();
- if (adapterLength > 0) {
- return adapterLength;
- }
- String maxText = null;
- int addItems = visibleItems / 2;
- for (int i = Math.max(currentItem - addItems, 0);
- i < Math.min(currentItem + visibleItems, adapter.getItemsCount()); i++) {
- String text = adapter.getItem(i);
- if (text != null && (maxText == null || maxText.length() < text.length())) {
- maxText = text;
- }
- }
- return maxText != null ? maxText.length() : 0;
- }
- /**
- * 返回滚轮item的高度
- * @return the item height
- */
- private int getItemHeight() {
- if (itemHeight != 0) {
- return itemHeight;
- } else if (itemsLayout != null && itemsLayout.getLineCount() > 2) {
- itemHeight = itemsLayout.getLineTop(2) - itemsLayout.getLineTop(1);
- return itemHeight;
- }
- return getHeight() / visibleItems;
- }
- /**
- * 计算控制宽度和创建text布局
- * @param widthSize the input layout width
- * @param mode the layout mode
- * @return the calculated control width
- */
- private int calculateLayoutWidth(int widthSize, int mode) {
- initResourceIfNecessary();
- int width = widthSize;
- int maxLength = getMaxTextLength();
- if (maxLength > 0) {
- float textWidth = FloatMath.ceil(Layout.getDesiredWidth("0", itemsPaint));
- itemsWidth = (int) (maxLength * textWidth);
- } else {
- itemsWidth = 0;
- }
- itemsWidth += ADDITIONAL_ITEMS_SPACE; // make it some more
- labelWidth = 0;
- if (label != null && label.length() > 0) {
- labelWidth = (int) FloatMath.ceil(Layout.getDesiredWidth(label, valuePaint));
- }
- boolean recalculate = false;
- if (mode == MeasureSpec.EXACTLY) {
- width = widthSize;
- recalculate = true;
- } else {
- width = itemsWidth + labelWidth + 2 * PADDING;
- if (labelWidth > 0) {
- width += LABEL_OFFSET;
- }
- // Check against our minimum width
- width = Math.max(width, getSuggestedMinimumWidth());
- if (mode == MeasureSpec.AT_MOST && widthSize < width) {
- width = widthSize;
- recalculate = true;
- }
- }
- if (recalculate) {
- // recalculate width
- int pureWidth = width - LABEL_OFFSET - 2 * PADDING;
- if (pureWidth <= 0) {
- itemsWidth = labelWidth = 0;
- }
- if (labelWidth > 0) {
- double newWidthItems = (double) itemsWidth * pureWidth
- / (itemsWidth + labelWidth);
- itemsWidth = (int) newWidthItems;
- labelWidth = pureWidth - itemsWidth;
- } else {
- itemsWidth = pureWidth + LABEL_OFFSET; // no label
- }
- }
- if (itemsWidth > 0) {
- createLayouts(itemsWidth, labelWidth);
- }
- return width;
- }
- /**
- * 创建布局
- * @param widthItems width of items layout
- * @param widthLabel width of label layout
- */
- private void createLayouts(int widthItems, int widthLabel) {
- if (itemsLayout == null || itemsLayout.getWidth() > widthItems) {
- itemsLayout = new StaticLayout(buildText(isScrollingPerformed), itemsPaint, widthItems,
- widthLabel > 0 ? Layout.Alignment.ALIGN_OPPOSITE : Layout.Alignment.ALIGN_CENTER,
- 1, ADDITIONAL_ITEM_HEIGHT, false);
- } else {
- itemsLayout.increaseWidthTo(widthItems);
- }
- if (!isScrollingPerformed && (valueLayout == null || valueLayout.getWidth() > widthItems)) {
- String text = getAdapter() != null ? getAdapter().getItem(currentItem) : null;
- valueLayout = new StaticLayout(text != null ? text : "",
- valuePaint, widthItems, widthLabel > 0 ?
- Layout.Alignment.ALIGN_OPPOSITE : Layout.Alignment.ALIGN_CENTER,
- 1, ADDITIONAL_ITEM_HEIGHT, false);
- } else if (isScrollingPerformed) {
- valueLayout = null;
- } else {
- valueLayout.increaseWidthTo(widthItems);
- }
- if (widthLabel > 0) {
- if (labelLayout == null || labelLayout.getWidth() > widthLabel) {
- labelLayout = new StaticLayout(label, valuePaint,
- widthLabel, Layout.Alignment.ALIGN_NORMAL, 1,
- ADDITIONAL_ITEM_HEIGHT, false);
- } else {
- labelLayout.increaseWidthTo(widthLabel);
- }
- }
- }
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
- int widthMode = MeasureSpec.getMode(widthMeasureSpec);
- int heightMode = MeasureSpec.getMode(heightMeasureSpec);
- int widthSize = MeasureSpec.getSize(widthMeasureSpec);
- int heightSize = MeasureSpec.getSize(heightMeasureSpec);
- int width = calculateLayoutWidth(widthSize, widthMode);
- int height;
- if (heightMode == MeasureSpec.EXACTLY) {
- height = heightSize;
- } else {
- height = getDesiredHeight(itemsLayout);
- if (heightMode == MeasureSpec.AT_MOST) {
- height = Math.min(height, heightSize);
- }
- }
- setMeasuredDimension(width, height);
- }
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- if (itemsLayout == null) {
- if (itemsWidth == 0) {
- calculateLayoutWidth(getWidth(), MeasureSpec.EXACTLY);
- } else {
- createLayouts(itemsWidth, labelWidth);
- }
- }
- if (itemsWidth > 0) {
- canvas.save();
- // Skip padding space and hide a part of top and bottom items
- canvas.translate(PADDING, -ITEM_OFFSET);
- drawItems(canvas);
- drawValue(canvas);
- canvas.restore();
- }
- drawCenterRect(canvas);
- drawShadows(canvas);
- }
- /**
- * 在顶部和底部画阴影的控制
- * @param canvas the canvas for drawing
- */
- private void drawShadows(Canvas canvas) {
- topShadow.setBounds(0, 0, getWidth(), getHeight() / visibleItems);
- topShadow.draw(canvas);
- bottomShadow.setBounds(0, getHeight() - getHeight() / visibleItems,
- getWidth(), getHeight());
- bottomShadow.draw(canvas);
- }
- /**
- * 画value和标签的布局
- * @param canvas the canvas for drawing
- */
- private void drawValue(Canvas canvas) {
- valuePaint.setColor(VALUE_TEXT_COLOR);
- valuePaint.drawableState = getDrawableState();
- Rect bounds = new Rect();
- itemsLayout.getLineBounds(visibleItems / 2, bounds);
- // draw label
- if (labelLayout != null) {
- canvas.save();
- canvas.translate(itemsLayout.getWidth() + LABEL_OFFSET, bounds.top);
- labelLayout.draw(canvas);
- canvas.restore();
- }
- // draw current value
- if (valueLayout != null) {
- canvas.save();
- canvas.translate(0, bounds.top + scrollingOffset);
- valueLayout.draw(canvas);
- canvas.restore();
- }
- }
- /**
- * 画items
- * @param canvas the canvas for drawing
- */
- private void drawItems(Canvas canvas) {
- canvas.save();
- int top = itemsLayout.getLineTop(1);
- canvas.translate(0, - top + scrollingOffset);
- itemsPaint.setColor(ITEMS_TEXT_COLOR);
- itemsPaint.drawableState = getDrawableState();
- itemsLayout.draw(canvas);
- canvas.restore();
- }
- /**
- * 画当前值的矩形
- * @param canvas the canvas for drawing
- */
- private void drawCenterRect(Canvas canvas) {
- int center = getHeight() / 2;
- int offset = getItemHeight() / 2;
- centerDrawable.setBounds(0, center - offset, getWidth(), center + offset);
- centerDrawable.draw(canvas);
- }
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- WheelAdapter adapter = getAdapter();
- if (adapter == null) {
- return true;
- }
- if (!gestureDetector.onTouchEvent(event) && event.getAction() == MotionEvent.ACTION_UP) {
- justify();
- }
- return true;
- }
- /**
- * 滚动滚轮
- * @param delta the scrolling value
- */
- private void doScroll(int delta) {
- scrollingOffset += delta;
- int count = scrollingOffset / getItemHeight();
- int pos = currentItem - count;
- if (isCyclic && adapter.getItemsCount() > 0) {
- // fix position by rotating
- while (pos < 0) {
- pos += adapter.getItemsCount();
- }
- pos %= adapter.getItemsCount();
- } else if (isScrollingPerformed) {
- //
- if (pos < 0) {
- count = currentItem;
- pos = 0;
- } else if (pos >= adapter.getItemsCount()) {
- count = currentItem - adapter.getItemsCount() + 1;
- pos = adapter.getItemsCount() - 1;
- }
- } else {
- // fix position
- pos = Math.max(pos, 0);
- pos = Math.min(pos, adapter.getItemsCount() - 1);
- }
- int offset = scrollingOffset;
- if (pos != currentItem) {
- setCurrentItem(pos, false);
- } else {
- invalidate();
- }
- // update offset
- scrollingOffset = offset - count * getItemHeight();
- if (scrollingOffset > getHeight()) {
- scrollingOffset = scrollingOffset % getHeight() + getHeight();
- }
- }
- // gesture listener
- private SimpleOnGestureListener gestureListener = new SimpleOnGestureListener() {
- public boolean onDown(MotionEvent e) {
- if (isScrollingPerformed) {
- scroller.forceFinished(true);
- clearMessages();
- return true;
- }
- return false;
- }
- public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
- startScrolling();
- doScroll((int)-distanceY);
- return true;
- }
- public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
- lastScrollY = currentItem * getItemHeight() + scrollingOffset;
- int maxY = isCyclic ? 0x7FFFFFFF : adapter.getItemsCount() * getItemHeight();
- int minY = isCyclic ? -maxY : 0;
- scroller.fling(0, lastScrollY, 0, (int) -velocityY / 2, 0, 0, minY, maxY);
- setNextMessage(MESSAGE_SCROLL);
- return true;
- }
- };
- // Messages
- private final int MESSAGE_SCROLL = 0;
- private final int MESSAGE_JUSTIFY = 1;
- /**
- * Set next message to queue. Clears queue before.
- *
- * @param message the message to set
- */
- private void setNextMessage(int message) {
- clearMessages();
- animationHandler.sendEmptyMessage(message);
- }
- /**
- * Clears messages from queue
- */
- private void clearMessages() {
- animationHandler.removeMessages(MESSAGE_SCROLL);
- animationHandler.removeMessages(MESSAGE_JUSTIFY);
- }
- // animation handler
- private Handler animationHandler = new Handler() {
- public void handleMessage(Message msg) {
- scroller.computeScrollOffset();
- int currY = scroller.getCurrY();
- int delta = lastScrollY - currY;
- lastScrollY = currY;
- if (delta != 0) {
- doScroll(delta);
- }
- // scrolling is not finished when it comes to final Y
- // so, finish it manually
- if (Math.abs(currY - scroller.getFinalY()) < MIN_DELTA_FOR_SCROLLING) {
- currY = scroller.getFinalY();
- scroller.forceFinished(true);
- }
- if (!scroller.isFinished()) {
- animationHandler.sendEmptyMessage(msg.what);
- } else if (msg.what == MESSAGE_SCROLL) {
- justify();
- } else {
- finishScrolling();
- }
- }
- };
- /**
- * Justifies wheel
- */
- private void justify() {
- if (adapter == null) {
- return;
- }
- lastScrollY = 0;
- int offset = scrollingOffset;
- int itemHeight = getItemHeight();
- boolean needToIncrease = offset > 0 ? currentItem < adapter.getItemsCount() : currentItem > 0;
- if ((isCyclic || needToIncrease) && Math.abs((float) offset) > (float) itemHeight / 2) {
- if (offset < 0)
- offset += itemHeight + MIN_DELTA_FOR_SCROLLING;
- else
- offset -= itemHeight + MIN_DELTA_FOR_SCROLLING;
- }
- if (Math.abs(offset) > MIN_DELTA_FOR_SCROLLING) {
- scroller.startScroll(0, 0, 0, offset, SCROLLING_DURATION);
- setNextMessage(MESSAGE_JUSTIFY);
- } else {
- finishScrolling();
- }
- }
- /**
- * 开始滚动
- */
- private void startScrolling() {
- if (!isScrollingPerformed) {
- isScrollingPerformed = true;
- notifyScrollingListenersAboutStart();
- }
- }
- /**
- * 停止滚动
- */
- void finishScrolling() {
- if (isScrollingPerformed) {
- notifyScrollingListenersAboutEnd();
- isScrollingPerformed = false;
- }
- invalidateLayouts();
- invalidate();
- }
- public void scroll(int itemsToScroll, int time) {
- scroller.forceFinished(true);
- lastScrollY = scrollingOffset;
- int offset = itemsToScroll * getItemHeight();
- scroller.startScroll(0, lastScrollY, 0, offset - lastScrollY, time);
- setNextMessage(MESSAGE_SCROLL);
- startScrolling();
- }
- }