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

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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;
}
}

@Override
protected 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());

}*/
};

@Override
protected 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;
}

}

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