先看效果图：
这里。我们自定义了一个Textview
package com.example.myscroltextview.view;
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;
public class ScrollTextView extends TextView {
/**
* 每行的字符串
*/
ArrayList<String> 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;
public String getScrollText() {
return scrollText;
}
public void setScrollText(String scrollText) {
this.scrollText = scrollText;
reset();
}
/**
* 重置
*/
private void reset() {
requestLayout();
invalidate();
currentY = 0;
}
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
*/
int delayTime = 10;
/**
* 每次滚动的距离
*/
float speed = 15.5f;
/**
* 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();
handler.sendEmptyMessageDelayed(0, delayTime);
break;
}
case 1: {
currentY += msg.arg1;
resetCurrentY();
invalidate();
}
}
}
/**
* 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();
// 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();
for (int i = 0; i < str.length(); i++) {
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 {
add = "" + c;
}
tempStringBuffer.append(add);
String temp = tempStringBuffer.toString();
float width = getPaint().measureText(temp.toString());
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 == ‘ ‘) {
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;
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;
}
}
我们的Activity：
package com.example.myscroltextview;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import com.example.myscroltextview.view.MyScrollTextView;
public class MyMainActivity extends Activity {
private MyScrollTextView ball1, ball2, ball3, ball4, ball5, ball6, ball7;
private Button changeButton;
private TimerTask task;
private Timer timer = new Timer();
private final Boolean[] isUp = {false, true};
private int time;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity_main);
ball1 = (MyScrollTextView) findViewById(R.id.myscroll1);
ball2 = (MyScrollTextView) findViewById(R.id.myscroll2);
ball3 = (MyScrollTextView) findViewById(R.id.myscroll3);
ball4 = (MyScrollTextView) findViewById(R.id.myscroll4);
ball5 = (MyScrollTextView) findViewById(R.id.myscroll5);
ball6 = (MyScrollTextView) findViewById(R.id.myscroll6);
ball7 = (MyScrollTextView) findViewById(R.id.myscroll7);
changeButton = (Button) findViewById(R.id.my_button_update);
// final List<String> strs = new ArrayList<String>();
// strs.add("xx01\t02\t03\t04\t05\t06\t07\t08\t09\t10\t11\t12\t13\t14\t15\t16\t17\t18\t19\t20\t21\t22\t23\t24\t25\t26\t27\t28\t29\t30\t31\t32\t33\t34\t35");
// strs.add("yy01\n02\n03\n04\n05\n06\n07\n08\n09\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30\n31\n32\n33\n34\n35");
final List<String> ssqRed = new ArrayList<String>();
//ssqRed.add("01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33");
ssqRed.add("0102030405060708091011121314151617181920212223242526272829303132333");
final List<String> ssqBlue = new ArrayList<String>();
ssqBlue.add("01020304050607080910111213141516");
final List<String> dltRed = new ArrayList<String>();
dltRed.add("0102030405060708091011121314151617181920212223242526272829303132333435");
final List<String> dltBlue = new ArrayList<String>();
dltBlue.add("010203040506070809101112");
changeButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ball1.setText("");
ball2.setText("");
ball3.setText("");
ball4.setText("");
ball5.setText("");
ball6.setText("");
ball7.setText("");
time = 2;
task = new TimerTask() {
@Override
public void run() {
runOnUiThread(new Runnable() { // UI thread
@Override
public void run() {
time--;
if (time <= 0) {
ball1.stop();
ball2.stop();
ball3.stop();
ball4.stop();
ball5.stop();
ball6.stop();
ball7.stop();
ball1.setScrollText("");
ball2.setScrollText("");
ball3.setScrollText("");
ball4.setScrollText("");
ball5.setScrollText("");
ball6.setScrollText("");
ball7.setScrollText("");
ball1.setText("02");
ball2.setText("06");
ball3.setText("24");
ball4.setText("06");
ball5.setText("14");
ball6.setText("27");
ball7.setText("11");
task.cancel();
} else {
int i = (int) (ssqRed.size() * Math.random());
ball1.setScrollText(ssqRed.get(i));
ball2.setScrollText(ssqRed.get(i));
ball3.setScrollText(ssqRed.get(i));
ball4.setScrollText(ssqRed.get(i));
ball5.setScrollText(ssqRed.get(i));
ball6.setScrollText(ssqRed.get(i));
ball7.setScrollText(ssqBlue.get(i));
Random random = new Random();
random.nextInt(2); // [0,2)
ball1.isUp = isUp[random.nextInt(2)];
ball2.isUp = isUp[random.nextInt(2)];
ball3.isUp = isUp[random.nextInt(2)];
ball4.isUp = isUp[random.nextInt(2)];
ball5.isUp = isUp[random.nextInt(2)];
ball6.isUp = isUp[random.nextInt(2)];
ball7.isUp = isUp[random.nextInt(2)];
}
}
});
}
};
timer.schedule(task, 0, 1000);
}
});
}
}
我们可以控制每个球的速度，这里我们采用随机数，是的每个球的速度都不一致，而且都在一定范围内，
我们还可以控制每个球的方向，向上或者向下。
这里提供一个demo的下载http://download.csdn.net/detail/lgx06/8295737