android实现垂直方向跑马灯效果

因为最近公司要做一个抽奖功能，里面有一个模块就是中奖用户，对中奖用户实现垂直方向跑马灯效果，最先的思想方式是类似歌词，做了n久，发现刷屏时间会有问题，特自己写了一个控件，希望能帮到大家

“`

package com.demo.xsl.text;

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Canvas;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.TextView;

/**
* 文本垂直滚动
* @author eandroidhu
*
*/
public class ScrollTextView extends TextView {
/**
* 每行的字符串
*/
ArrayList lineStrings;

/** * 当前的位移 */float currentY;/** * 处理滚动消息 */Handler handler;/** * 要显示的text */String scrollText="";/** * 真实宽度,在配置width="xxdp"里起作用 */private int exactlyWidth = -1;/** * 真实高度,在配置height="xxdip"里起作用  */private int exactlyHeight = -1;private float index = 0;public String getScrollText() {    return scrollText;}public void setScrollText(String scrollText) {    this.scrollText = scrollText;    reset();}/** * 重置 */private void reset() {    if(lineStrings!=null)    lineStrings.clear();    stop();    currentY = 0;    absloutHeight = 0;    this.setText("");    if(handler!=null){        handler.removeMessages(0);        handler.removeMessages(1);        handler.removeMessages(2);        handler.removeMessages(3);    }    requestLayout();    invalidate();}public ScrollTextView(Context context, AttributeSet attrs) {    super(context, attrs);    init();}public ScrollTextView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);    init();}public ScrollTextView(Context context) {    super(context);    init();}/** * 是否在滚动 */boolean scrolling = false;/** * 实际高度：所有字显示完全需要的高度 */float absloutHeight = 0;/** * handler发消息的时间间隔 */

private int delayTime = 10; //滚动时间
private int stopTime = 3000; //停休时间

public int getDelayTime() {return delayTime;

}

public void setDelayTime(int delayTime) {
this.delayTime = delayTime;
}

public int getStopTime() {
return stopTime;
}

public void setStopTime(int stopTime) {
this.stopTime = stopTime;
}

/** * 每次滚动的距离 */float speed = 0.5f;/** * 初始化 */void init() {    handler = new Handler() {        @Override        public void handleMessage(Message msg) {            if (absloutHeight <= getHeight()) {                currentY = 0;                stop();                return;            }            switch (msg.what) {                case 0: {                    currentY = currentY - speed;                    //resetCurrentY();                    invalidate();                    boolean flag = true;                    if (currentY >= absloutHeight || currentY <= -absloutHeight) {                        flag = false;                        handler.sendEmptyMessageDelayed(3, stopTime);                    }                    if(flag){                          if (currentY >=  index|| currentY <= -index || getHeight() <= 0) {                              handler.sendEmptyMessageDelayed(2, stopTime);                          }else{                             handler.sendEmptyMessageDelayed(0, delayTime);                          }                    }                    break;                }                case 1: {                    currentY += msg.arg1;                    resetCurrentY();                    invalidate();                }                break;                case 2:{                    index = index+absloutHeight/lineStrings.size();                     stop();                     handler.sendEmptyMessageDelayed(0, delayTime);                }                break;                case 3:{                     currentY = 0;                     index = absloutHeight/lineStrings.size();;                     stop();                     handler.sendEmptyMessageDelayed(0, delayTime);                }            }        }        /**         * 重置currentY（当currentY超过absloutHeight时，让它重置为0）         */        private void resetCurrentY() {            if (currentY >= absloutHeight || currentY <= -absloutHeight || getHeight() <= 0) {                currentY = 0;            }        }    };}/** * 上次触发事件的手指y坐标 */float lastY = 0;/** * 为true代表原来是滚动 */boolean needStop;public void pause() {    if (scrolling) {        stop();        needStop = true;    }}public void goOn() {    if (needStop) {        play();        needStop = false;    }}

/* @Override
public boolean onTouchEvent(MotionEvent event) {

    switch (event.getAction()) {        case MotionEvent.ACTION_DOWN:            distanceY = lastY = event.getY();            distanceX = event.getX();            pause();            return true;        case MotionEvent.ACTION_MOVE:            float dy = event.getY() - lastY;            lastY = event.getY();            // currentY = currentY + dy;            Message msg = Message.obtain();            msg.what = 1;            msg.arg1 = (int)dy;            handler.sendMessage(msg);            return true;        case MotionEvent.ACTION_UP:        case MotionEvent.ACTION_CANCEL:            goOn();            float y = event.getY() - distanceY;            float x = event.getX() - distanceX;            if (Math.sqrt(y * y + x * x) < performUpScrollStateDistance) {                updateScrollStatus();            }            return true;    }    return super.onTouchEvent(event);}

*/
/**
* 当手指移动此大小的距离以内，被认为是滚动状态改变的事件，大于该值代表是手指搬运
*/
public static final long performUpScrollStateDistance = 5;

public float distanceY = 0;public float distanceX = 0;/** * 更改滚动状态 */public void updateScrollStatus() {    if (scrolling) {        stop();    } else {        play();    }}/** * 开始滚动 */public void play() {    if (!scrolling) {        handler.sendEmptyMessage(0);        scrolling = true;    }}/** * 停止滚动 */public void stop() {    if (scrolling) {        handler.removeMessages(0);        scrolling = false;    }}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    int width = MeasureWidth(widthMeasureSpec);    int height = MeasureHeight(width, heightMeasureSpec);    setMeasuredDimension(width, height);    currentY = 0;    if (height < absloutHeight) {        play();    } else {        stop();    }}/** * 测量宽度 *  * @param widthMeasureSpec * @return */private int MeasureWidth(int widthMeasureSpec) {    int mode = MeasureSpec.getMode(widthMeasureSpec);    int width = MeasureSpec.getSize(widthMeasureSpec);    // 如果是wrap_content    if (mode == MeasureSpec.AT_MOST) {        double abwidth = getPaint().measureText(scrollText);        width = Math.min((int)Math.rint(abwidth), width);        exactlyWidth = -1;    }    if (mode == MeasureSpec.EXACTLY) {        exactlyWidth = width;    }    return width;}/** * 测量高度 *  * @param width:宽度 * @param heightMeasureSpec * @return */private int MeasureHeight(int width, int heightMeasureSpec) {    int mode = MeasureSpec.getMode(heightMeasureSpec);    int height = MeasureSpec.getSize(heightMeasureSpec);    generateTextList(width);    int lines = lineStrings.size();    absloutHeight = lines * getLineHeight() + getPaddingBottom() + getPaddingTop();    index = absloutHeight/lines;    // 如果是wrap_content    if (mode == MeasureSpec.AT_MOST) {        height = (int)Math.min(absloutHeight, height);        exactlyHeight = -1;    } else if (mode == MeasureSpec.EXACTLY) {        exactlyHeight = height;    }    return height;}/** * 是否为英文单词的首字母 *  * @param str * @param i * @return */boolean isENWordStart(String str, int i) {    if (i == 0) {        return true;    } else if (str.charAt(i - 1) == ' ') {        return true;    }    return false;}/** * 获取一行的字符 *  * @param MaxWidth * @param str * @return */private String getLineText(int MaxWidth, String str) {    // 真实行    StringBuffer trueStringBuffer = new StringBuffer();    // 临时行    StringBuffer tempStringBuffer = new StringBuffer();    boolean isLine;    for (int i = 0; i < str.length(); i++) {        isLine = false;        char c = str.charAt(i);        String add = "";        // 如果c是字母需要考虑英文单词换行功能        if (!isChinese(c) && isENWordStart(str, i)) {            int place = getNextSpecePlace(i, str);            // 找到下一个空格            if (place > -1) {                add = str.substring(i, place) + " ";                if (getPaint().measureText(add) > MaxWidth) {                    add = "" + c;                } else {                    i = place;                }            } else {                add = "" + c;            }        } else {            if(c=='\n') { //判断是否到了换行的标示符                isLine = true;                 add = "" + c;            }else            add = "" + c;        }        tempStringBuffer.append(add);        String temp = tempStringBuffer.toString();        float width = getPaint().measureText(temp.toString());        if(isLine)            break;        if (width <= MaxWidth) {            trueStringBuffer.append(add);        } else {            break;        }    }    return trueStringBuffer.toString();}/** * 找到下一个空格的地方 *  * @param i * @param str * @return */int getNextSpecePlace(int i, String str) {    for (int j = i; j < str.length(); j++) {        char c = str.charAt(j);        if (c == '\n') {            return j;        }    }    return -1;}/** * 生成多行字符串列表 *  * @param MaxWidth */public void generateTextList(int MaxWidth) {    lineStrings = new ArrayList<String>();   // String remain = scrollText;    String[] contenx = scrollText.split("k#");    for (String string : contenx) {           lineStrings.add(string);    } /*   while (!remain.equals("")) {        String line = getLineText(MaxWidth, remain);        lineStrings.add(line);        remain = remain.substring(line.length(), remain.length());    }*/};@Overrideprotected void onDraw(Canvas canvas) {    super.onDraw(canvas);    float x = getPaddingLeft();    float y = getPaddingTop();    float lineHeight = getLineHeight();    float textSize = getPaint().getTextSize();    for (int i = 0; i < lineStrings.size(); i++) {        y = lineHeight * i + textSize + currentY;        float min = 0;        if (exactlyHeight > -1) {            min = Math.min(min, exactlyHeight - absloutHeight);        }        if (y < min) {            y = y + absloutHeight;        } else if (y >= min && y < textSize + min) {            //如果最顶端的文字已经到达需要循环从下面滚出的时候            canvas.drawText(lineStrings.get(i), x, y + absloutHeight, getPaint());        }        if (y >= absloutHeight) {            //如果最底端的文字已经到达需要循环从上面滚出的时候            canvas.drawText(lineStrings.get(i), x, y, getPaint());            y = y - absloutHeight;        }        canvas.drawText(lineStrings.get(i), x, y, getPaint());    }}/** * 判断是否为中文 *  * @param c * @return */private static final boolean isChinese(char c) {    Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);    if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS            || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS            || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A            || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION            || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION            || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {        return true;    }    return false;}

}
源码下载链接