本篇文章给大家分享的是有关Android仿iPhone的时间轮的工具怎么用，小编觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着小编一起来看看吧。
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(); } }以上就是Android仿iPhone的时间轮的工具怎么用，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注亿速云行业资讯频道。
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