android 时间滚动控件 底部弹出

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先上个效果图

第一步：先自定义一个View

package com.wheel.widget;

import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.example.mywheel.R;

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.DisplayMetrics;
import android.util.FloatMath;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.Interpolator;
import android.widget.Scroller;

public class WheelView extends View {
	/** Scrolling duration */
	private static final int SCROLLING_DURATION = 400;

	/** Minimum delta for scrolling */
	private static final int MIN_DELTA_FOR_SCROLLING = 1;

	/** Current value & label text color */
	public static int VALUE_TEXT_COLOR = 0xe0000000;
	/** Items text color */
	private static final int ITEMS_TEXT_COLOR = 0xe0000000;

	/** Top and bottom shadows colors */
	private static final int[] SHADOWS_COLORS = new int[] { 0x00000000,
		0x00000000, 0x00000000 };

	/** Additional items height (is added to standard text item height) */
	private static final int ADDITIONAL_ITEM_HEIGHT = 15;

	/** Text size */
	private static final int TEXT_SIZE = 15;

	/** Top and bottom items offset (to hide that) */
	private static final int ITEM_OFFSET = TEXT_SIZE / 5;

	/** Additional width for items layout */
	private static final int ADDITIONAL_ITEMS_SPACE = 10;

	/** Label offset */
	private static final int LABEL_OFFSET = 8;

	/** Left and right padding value */
	private static final int PADDING = 5;

	/** Default count of visible items */
	private static final int DEF_VISIBLE_ITEMS = 5;

	// Wheel Values
	private WheelAdapter adapter = null;
	private int currentItem = 0;
	
	// Widths
	private int itemsWidth = 0;
	private int labelWidth = 0;

	// Count of visible items
	private int visibleItems = DEF_VISIBLE_ITEMS;
	
	// Item height
	private int itemHeight = 0;

	// Text paints
	private TextPaint itemsPaint;
	private TextPaint valuePaint;

	// Layouts
	private StaticLayout itemsLayout;
	private StaticLayout labelLayout;
	private StaticLayout valueLayout;

	// Label & background
	private String label;
	private Drawable centerDrawable;

	// Shadows drawables
	private GradientDrawable topShadow;
	private GradientDrawable bottomShadow;

	// Scrolling
	private boolean isScrollingPerformed; 
	private int scrollingOffset;

	// Scrolling animation
	private GestureDetector gestureDetector;
	private Scroller scroller;
	private int lastScrollY;

	// Cyclic
	boolean isCyclic = true;
	
	// Listeners
	private List changingListeners = new LinkedList();
	private List scrollingListeners = new LinkedList();

	/**
	 * Constructor
	 */
	public WheelView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		initData(context);
	}

	/**
	 * Constructor
	 */
	public WheelView(Context context, AttributeSet attrs) {
		super(context, attrs);
		initData(context);
	}

	/**
	 * Constructor
	 */
	public WheelView(Context context) {
		super(context);
		initData(context);
	}
	
	/**
	 * Initializes class data
	 * @param context the context
	 */
	private void initData(Context context) {
		gestureDetector = new GestureDetector(context, gestureListener);
		gestureDetector.setIsLongpressEnabled(false);
		
		scroller = new Scroller(context);
	}
	
	/**
	 * Gets wheel adapter
	 * @return the adapter
	 */
	public WheelAdapter getAdapter() {
		return adapter;
	}
	
	/**
	 * Sets wheel adapter
	 * @param adapter the new wheel adapter
	 */
	public void setAdapter(WheelAdapter adapter) {
		this.adapter = adapter;
		invalidateLayouts();
		invalidate();
	}
	
	/**
	 * Set the the specified scrolling interpolator
	 * @param interpolator the interpolator
	 */
	public void setInterpolator(Interpolator interpolator) {
		scroller.forceFinished(true);
		scroller = new Scroller(getContext(), interpolator);
	}
	
	/**
	 * Gets count of visible items
	 * 
	 * @return the count of visible items
	 */
	public int getVisibleItems() {
		return visibleItems;
	}

	/**
	 * Sets count of visible items
	 * 
	 * @param count
	 *            the new count
	 */
	public void setVisibleItems(int count) {
		visibleItems = count;
		invalidate();
	}

	/**
	 * Gets label
	 * 
	 * @return the label
	 */
	public String getLabel() {
		return label;
	}

	/**
	 * Sets label
	 * 
	 * @param newLabel
	 *            the label to set
	 */
	public void setLabel(String newLabel) {
		if (label == null || !label.equals(newLabel)) {
			label = newLabel;
			labelLayout = null;
			invalidate();
		}
	}
	
	/**
	 * Adds wheel changing listener
	 * @param listener the listener 
	 */
	public void addChangingListener(OnWheelChangedListener listener) {
		changingListeners.add(listener);
	}

	/**
	 * Removes wheel changing listener
	 * @param listener the listener
	 */
	public void removeChangingListener(OnWheelChangedListener listener) {
		changingListeners.remove(listener);
	}
	
	/**
	 * Notifies changing listeners
	 * @param oldValue the old wheel value
	 * @param newValue the new wheel value
	 */
	protected void notifyChangingListeners(int oldValue, int newValue) {
		for (OnWheelChangedListener listener : changingListeners) {
			listener.onChanged(this, oldValue, newValue);
		}
	}

	/**
	 * Adds wheel scrolling listener
	 * @param listener the listener 
	 */
	public void addScrollingListener(OnWheelScrollListener listener) {
		scrollingListeners.add(listener);
	}

	/**
	 * Removes wheel scrolling listener
	 * @param listener the listener
	 */
	public void removeScrollingListener(OnWheelScrollListener listener) {
		scrollingListeners.remove(listener);
	}
	
	/**
	 * Notifies listeners about starting scrolling
	 */
	protected void notifyScrollingListenersAboutStart() {
		for (OnWheelScrollListener listener : scrollingListeners) {
			listener.onScrollingStarted(this);
		}
	}

	/**
	 * Notifies listeners about ending scrolling
	 */
	protected void notifyScrollingListenersAboutEnd() {
		for (OnWheelScrollListener listener : scrollingListeners) {
			listener.onScrollingFinished(this);
		}
	}

	/**
	 * Gets current value
	 * 
	 * @return the current value
	 */
	public int getCurrentItem() {
		return currentItem;
	}

	/**
	 * Sets the current item. Does nothing when index is wrong.
	 * 
	 * @param index the item index
	 * @param animated the animation flag
	 */
	public void setCurrentItem(int index, boolean animated) {
		if (adapter == null || adapter.getItemsCount() == 0) {
			return; // throw?
		}
		if (index < 0 || index >= adapter.getItemsCount()) {
			if (isCyclic) {
				while (index < 0) {
					index += adapter.getItemsCount();
				}
				index %= adapter.getItemsCount();
			} else{
				return; // throw?
			}
		}
		if (index != currentItem) {
			if (animated) {
				scroll(index - currentItem, SCROLLING_DURATION);
			} else {
				invalidateLayouts();
			
				int old = currentItem;
				currentItem = index;
			
				notifyChangingListeners(old, currentItem);
			
				invalidate();
			}
		}
	}

	/**
	 * Sets the current item w/o animation. Does nothing when index is wrong.
	 * 
	 * @param index the item index
	 */
	public void setCurrentItem(int index) {
		setCurrentItem(index, false);
	}	
	
	/**
	 * Tests if wheel is cyclic. That means before the 1st item there is shown the last one
	 * @return true if wheel is cyclic
	 */
	public boolean isCyclic() {
		return isCyclic;
	}

	/**
	 * Set wheel cyclic flag
	 * @param isCyclic the flag to set
	 */
	public void setCyclic(boolean isCyclic) {
		this.isCyclic = isCyclic;
		
		invalidate();
		invalidateLayouts();
	}

	/**
	 * Invalidates layouts
	 */
	private void invalidateLayouts() {
		itemsLayout = null;
		valueLayout = null;
		scrollingOffset = 0;
	}

	/**
	 * Initializes resources
	 */
	private void initResourcesIfNecessary() {
		DisplayMetrics dm = this.getResources().getDisplayMetrics();
		int textsize = (int) (TEXT_SIZE* dm.density);
		
		if (itemsPaint == null) {
			itemsPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG
					| Paint.FAKE_BOLD_TEXT_FLAG);
			itemsPaint.density = getResources().getDisplayMetrics().density;
			
			itemsPaint.setTextSize(textsize);
		}

		if (valuePaint == null) {
			valuePaint = new TextPaint(Paint.ANTI_ALIAS_FLAG
					| Paint.FAKE_BOLD_TEXT_FLAG | Paint.DITHER_FLAG);
			//valuePaint.density = getResources().getDisplayMetrics().density;
			valuePaint.setTextSize(textsize);
			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);
	}

	/**
	 * Calculates desired height for layout
	 * 
	 * @param layout
	 *            the source layout
	 * @return the desired layout height
	 */
	private int getDesiredHeight(Layout layout) {
		if (layout == null) {
			return 0;
		}
		DisplayMetrics dm = this.getResources().getDisplayMetrics();
		int height = (int) (ADDITIONAL_ITEM_HEIGHT* dm.density);
		int desired = getItemHeight() * visibleItems - ITEM_OFFSET * 2
				- height;

		// Check against our minimum height
		desired = Math.max(desired, getSuggestedMinimumHeight());

		return desired;
	}

	/**
	 * Returns text item by index
	 * @param index the item index
	 * @return the item or null
	 */
	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;
			}
		}
		
		index %= count;
		return adapter.getItem(index);
	}
	
	/**
	 * Builds text depending on current value
	 * 
	 * @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();
	}

	/**
	 * Returns the max item length that can be present
	 * @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;
	}

	/**
	 * Returns height of wheel item
	 * @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;
	}

	/**
	 * Calculates control width and creates text layouts
	 * @param widthSize the input layout width
	 * @param mode the layout mode
	 * @return the calculated control width
	 */
	private int calculateLayoutWidth(int widthSize, int mode) {
		initResourcesIfNecessary();

		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;
	}

	/**
	 * Creates layouts
	 * @param widthItems width of items layout
	 * @param widthLabel width of label layout
	 */
	private void createLayouts(int widthItems, int widthLabel) {
		DisplayMetrics dm = this.getResources().getDisplayMetrics();
		int height = (int) (ADDITIONAL_ITEM_HEIGHT* dm.density);
		if (itemsLayout == null || itemsLayout.getWidth() > widthItems) {
			itemsLayout = new StaticLayout(buildText(isScrollingPerformed), itemsPaint, widthItems,
					widthLabel > 0 ? Layout.Alignment.ALIGN_OPPOSITE : Layout.Alignment.ALIGN_CENTER,
					1, 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, 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,
						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);
	}

	/**
	 * Draws shadows on top and bottom of control
	 * @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);
	}

	/**
	 * Draws value and label layout
	 * @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();
		}
	}

	/**
	 * Draws items
	 * @param canvas the canvas for drawing
	 */
	private void drawItems(Canvas canvas) {
		canvas.save();
		
		int top = itemsLayout.getLineTop(1);
		canvas.translate(0, - top + scrollingOffset);
		Logger.getLogger(WheelView.class.getName()).log(Level.WARNING, ".....top....>>"+top);
		Logger.getLogger(WheelView.class.getName()).log(Level.WARNING, "....scrollingOffset...>>"+scrollingOffset);
		itemsPaint.setColor(ITEMS_TEXT_COLOR);
		itemsPaint.drawableState = getDrawableState();
		itemsLayout.draw(canvas);
		
		canvas.restore();
	}

	/**
	 * Draws rect for current value
	 * @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;
	}
	
	/**
	 * Scrolls the wheel
	 * @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();
		}
	}
	
	/**
	 * Starts scrolling
	 */
	private void startScrolling() {
		if (!isScrollingPerformed) {
			isScrollingPerformed = true;
			notifyScrollingListenersAboutStart();
		}
	}

	/**
	 * Finishes scrolling
	 */
	void finishScrolling() {
		if (isScrollingPerformed) {
			notifyScrollingListenersAboutEnd();
			isScrollingPerformed = false;
		}
		invalidateLayouts();
		invalidate();
	}
	
	
	/**
	 * Scroll the wheel
	 * @param itemsToSkip items to scroll
	 * @param time scrolling duration
	 */
	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();
	}
	
	public int getScroolingOffset(){
		
		return scrollingOffset;
	}

}

里面可以修改字体大小颜色 间距等等

第二步，创建一个适配器

package com.wheel.widget;

/**
 * Numeric Wheel adapter.
 */
public class NumericWheelAdapter implements WheelAdapter {

	/** The default min value */
	public static final int DEFAULT_MAX_VALUE = 9;

	/** The default max value */
	private static final int DEFAULT_MIN_VALUE = 0;

	// Values
	private int minValue;
	private int maxValue;

	// Values
	private double minValue1;
	private double maxValue1;
	// format
	private String format;

	private String values = null;

	private String data[] = new String[215];

	/**
	 * Constructor
	 * 
	 * @param minValue
	 *            the wheel min value
	 * @param maxValue
	 *            the wheel max value
	 */
	public NumericWheelAdapter(int minValue, int maxValue) {
		this.minValue = minValue;
		this.maxValue = maxValue;
	}

	/**
	 * Constructor
	 * 
	 * @param minValue
	 *            the wheel min value
	 * @param maxValue
	 *            the wheel max value
	 * @param format
	 *            the format string
	 */
	public NumericWheelAdapter(int minValue, int maxValue, String format) {
		this.minValue = minValue;
		this.maxValue = maxValue;
		this.format = format;
	}

	public String getItem(int index) {
		if (index >= 0 && index < getItemsCount()) {
			int value = minValue + index;
			values = (format != null ? String.format(format, value) : Integer
					.toString(value));
			setValue(values);
			return values;
		}
		return null;
	}

	// 杩斿洖褰撳墠閫変腑鐨勫?
	public String getValues() {
		return values;
	}

	public void setValue(String value) {
		this.values = value;
	}

	public int getItemsCount() {
		return maxValue - minValue + 1;
	}

	// 得到最大项目长度。它是用来确定轮宽度。
	// 如果返回1,将使用默认轮宽度

	public int getMaximumLength() {
		int max = Math.max(Math.abs(maxValue), Math.abs(minValue));
		int maxLen = Integer.toString(max).length();
		if (minValue < 0) {
			maxLen++;
		}
		return maxValue - minValue + 1;
	}

}

第三步：布局文件

第四步 ： 自定义一个dialog

package com.wheel.view;

import java.util.Arrays;
import java.util.Calendar;
import java.util.List;

import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;

import com.example.mywheel.R;
import com.wheel.widget.NumericWheelAdapter;
import com.wheel.widget.OnWheelChangedListener;
import com.wheel.widget.WheelView;

/**
 * 日期选择�?
 * 
 * @author Administrator
 * 
 */
public class BirthDateDialog extends Dialog implements
		android.view.View.OnClickListener {
	/**
	 * 自定义Dialog监听�?
	 */
	public interface PriorityListener {
		/**
		 * 回调函数，用于在Dialog的监听事件触发后刷新Activity的UI显示
		 */
		public void refreshPriorityUI(String year, String month, String day,
				String hours, String mins);
	}

	private PriorityListener lis;
	private boolean scrolling = false;
	private Context context = null;
	public Button softInfo = null;
	public Button softInfoButton = null;
	private NumericWheelAdapter year_adapter = null;
	private NumericWheelAdapter month_adapter = null;
	private NumericWheelAdapter day_adapter = null;
	private NumericWheelAdapter hours_adapter = null;
	private NumericWheelAdapter mins_adapter = null;
	private NumericWheelAdapter seconds_adapter = null;
	private Button btn_sure = null;
	private Button btn_cancel = null;
	private int curYear = 0;
	private int curMonth = 0;
	private int curDay = 0;
	private int hours = 0;
	private int mins = 0;
	private int seconds = 0;
	private WheelView monthview = null;
	private WheelView yearview = null;
	private WheelView dayview = null;
	private WheelView hoursview = null;
	private WheelView minsview = null;
	private WheelView secondsview = null;
	private static int theme = R.style.myDialog;// 主题
	private LinearLayout date_layout;
	private int width, height;// 对话框宽高
	private TextView title_tv;
	private String title;

	public BirthDateDialog(final Context context,
			final PriorityListener listener, int currentyear, int currentmonth,
			int currentday, int hours, int mins, int seconds, int width,
			int height, String title) {
		super(context, theme);
		this.context = context;
		lis = listener;
		this.curYear = currentyear;
		this.curMonth = currentmonth;
		this.curDay = currentday;
		this.width = width;
		this.title = title;
		this.hours = hours;
		this.mins = mins;
		this.height = height;
		this.seconds = seconds;
	}

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.date_select_wheel);
		btn_sure = (Button) findViewById(R.id.confirm_btn);
		btn_sure.setOnClickListener(this);
		btn_cancel = (Button) findViewById(R.id.cancel_btn);
		btn_cancel.setOnClickListener(this);
		date_layout = (LinearLayout) findViewById(R.id.date_selelct_layout);
		LayoutParams lparams_hours = new LayoutParams(width, height / 3 + 10);
		date_layout.setLayoutParams(lparams_hours);
		title_tv = (TextView) findViewById(R.id.diaolog_title_tv);
		title_tv.setText(title);
		yearview = (WheelView) findViewById(R.id.year);
		monthview = (WheelView) findViewById(R.id.month);
		dayview = (WheelView) findViewById(R.id.day);
		hoursview = (WheelView) findViewById(R.id.hours);
		minsview = (WheelView) findViewById(R.id.mins);
		secondsview = (WheelView) findViewById(R.id.seconds);
		OnWheelChangedListener listener = new OnWheelChangedListener() {
			public void onChanged(WheelView wheel, int oldValue, int newValue) {
				if (!scrolling) {
					updateDays(yearview, monthview, dayview);
				}
			}
		};
		monthview.addChangingListener(listener);
		yearview.addChangingListener(listener);
		Calendar calendar = Calendar.getInstance();
		if (this.curYear == 0 || this.curMonth == 0) {
			curYear = calendar.get(Calendar.YEAR);
			curMonth = calendar.get(Calendar.MONTH) + 1;
			curDay = calendar.get(Calendar.DAY_OF_MONTH);
		}
		// 初始化数�?�?
		year_adapter = new NumericWheelAdapter(1900, 2100);
		yearview.setAdapter(year_adapter);
		int cc = curYear - 1900;// 按下标来�?
		yearview.setCurrentItem(cc);// 传�?过去的是下标
		yearview.setVisibleItems(5);
		month_adapter = new NumericWheelAdapter(1, 12, "%02d");
		monthview.setAdapter(month_adapter);
		monthview.setCurrentItem(curMonth - 1);
		monthview.setCyclic(false);
		monthview.setVisibleItems(5);
		updateDays(yearview, monthview, dayview);
		dayview.setCyclic(false);
		dayview.setVisibleItems(5);
		hours_adapter = new NumericWheelAdapter(0, 23, "%02d");
		hoursview.setAdapter(hours_adapter);
		hoursview.setCurrentItem(hours);
		hoursview.setCyclic(false);
		hoursview.setVisibleItems(5);
		mins_adapter = new NumericWheelAdapter(0, 59, "%02d");
		minsview.setAdapter(mins_adapter);
		minsview.setCurrentItem(mins);
		minsview.setCyclic(false);
		minsview.setVisibleItems(5);
		seconds_adapter = new NumericWheelAdapter(0, 59, "%02d");
		secondsview.setAdapter(seconds_adapter);
		secondsview.setCurrentItem(seconds);
		secondsview.setCyclic(false);
		secondsview.setVisibleItems(5);
	}

	/**
	 * 根据年份和月份来更新日期
	 */
	private void updateDays(WheelView year, WheelView month, WheelView day) {
		// 添加大小月月份并将其转换为list,方便之后的判�?
		String[] months_big = { "1", "3", "5", "7", "8", "10", "12" };
		String[] months_little = { "4", "6", "9", "11" };

		final List list_big = Arrays.asList(months_big);
		final List list_little = Arrays.asList(months_little);
		int year_num = year.getCurrentItem() + 1900;
		// 判断大小月及是否闰年,用来确定"�?的数�?
		if (list_big.contains(String.valueOf(month.getCurrentItem() + 1))) {
			day_adapter = new NumericWheelAdapter(1, 31, "%02d");
		} else if (list_little
				.contains(String.valueOf(month.getCurrentItem() + 1))) {
			day_adapter = new NumericWheelAdapter(1, 30, "%02d");
		} else {
			if ((year_num % 4 == 0 && year_num % 100 != 0)
					|| year_num % 400 == 0)
				day_adapter = new NumericWheelAdapter(1, 29, "%02d");
			else
				day_adapter = new NumericWheelAdapter(1, 28, "%02d");
		}
		dayview.setAdapter(day_adapter);
		dayview.setCurrentItem(curDay - 1);
	}

	public BirthDateDialog(Context context, PriorityListener listener) {
		super(context, theme);
		this.context = context;
	}

	public BirthDateDialog(Context context, String birthDate) {
		super(context, theme);
		this.context = context;

	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.confirm_btn:
			lis.refreshPriorityUI(year_adapter.getValues(),
					month_adapter.getValues(), day_adapter.getValues(),
					hours_adapter.getValues(), mins_adapter.getValues());

			this.dismiss();
			break;
		case R.id.cancel_btn:
			this.dismiss();
			break;
		default:
			break;
		}
	}

	@Override
	public void dismiss() {
		super.dismiss();
	}

	@Override
	protected void onStop() {
		super.onStop();
	}
}

第五步：dialog样式 在底部

// 时间
	public void getDate() {
		DisplayMetrics dm = new DisplayMetrics();
		this.getWindowManager().getDefaultDisplay().getMetrics(dm);
		int width = dm.widthPixels;
		int height = dm.heightPixels;
		String curDate = date_tv.getText().toString();
		int[] date = getYMDArray(curDate, "-");
		int[] time = getYMDArray(time_tv.getText().toString(), ":");
		BirthDateDialog birthDiolog = new BirthDateDialog(this,
				new PriorityListener() {
					@Override
					public void refreshPriorityUI(String year, String month,
							String day, String hours, String mins) {
						date_tv.setText(year + "-" + month + "-" + day);
						time_tv.setText(hours + ":" + mins);
					}
				}, date[0], date[1], date[2], time[0], time[1], time[2], width,
				height, "测量时间");
		Window window = birthDiolog.getWindow();
		window.setGravity(Gravity.BOTTOM); // 此处可以设置dialog显示的位置
		window.setWindowAnimations(R.style.dialogstyle); // 添加动画
		birthDiolog.setCancelable(true);
		birthDiolog.show();
	}

以上就是关键代码，待会会把整个项目贴上来  有不足之处 请多多谅解