android TextView实现实现跑马灯效果，并监听滚动完成动作。

package com.example.textviewtest;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.ViewDebug.ExportedProperty;
import android.widget.TextView;

public class MarqueeTextView extends TextView implements Runnable {

private static final int MARQUEE_DELAY = 1200;
private static final int MARQUEE_RESTART_DELAY = 10;

private int currentScrollX;
private boolean isStop = false;
private int textWidth;
private boolean isMeasure = false;
private int mMarqueeRepeatLimit = 1;
private int mMarqueeVelocity = 2;

private OnMarqueeCompleteListener marqueeCompleteListener;

public MarqueeTextView(Context context) {
this(context, null);
}

public MarqueeTextView(Context context, AttributeSet attrs) {
this(context, attrs,0);
}

public MarqueeTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mMarqueeRepeatLimit = getMarqueeRepeatLimit();
}

interface OnMarqueeCompleteListener {
void onMarqueeComplete();
}

public OnMarqueeCompleteListener getMarqueeCompleteListener() {
return marqueeCompleteListener;
}

public void setOnMarqueeCompleteListener(
OnMarqueeCompleteListener marqueeCompleteListener) {
this.marqueeCompleteListener = marqueeCompleteListener;
}

/**
* 获取文字滚动的速度，每秒移动的像素
* @return
*/
public int getMarqueeVelocity() {
return mMarqueeVelocity;
}

/**
* 设置文字的滚动的速度
* @param mMarqueeVelocity 每秒移动的像素
*/
public void setMarqueeVelocity(int velocity) {
this.mMarqueeVelocity = velocity ;
}

@Override
@ExportedProperty(category = "focus")
public boolean isFocused() {
return false;
}

@Override
@ExportedProperty
public boolean isSelected() {
return false;
}

@Override
public void setSelected(boolean selected) {
super.setSelected(selected);
startStopMarquee(selected);
}

@Override
protected void onFocusChanged(boolean focused, int direction,
Rect previouslyFocusedRect) {
super.onFocusChanged(focused, direction, previouslyFocusedRect);
startStopMarquee(focused);
}

public void startStopMarquee(boolean bool){
if(bool){
startScroll();
}else{
stopScroll();
}
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (!isMeasure) {
textWidth = getTextWidth();
isMeasure = true;
}
}

/**
* 获取文字宽度
*/
private int getTextWidth() {
Paint paint = this.getPaint();
String str = this.getText().toString();
return (int) paint.measureText(str);
}

@Override
public void run() {
if(textWidth <= getWidth()){
if(null != marqueeCompleteListener){
marqueeCompleteListener.onMarqueeComplete();
}
return;
}

if (isStop) {
currentScrollX = 0;
scrollTo(currentScrollX, 0);
return;
}

currentScrollX += mMarqueeVelocity;
scrollTo(currentScrollX, 0);

if (textWidth != 0  && getScrollX() >= textWidth) {
mMarqueeRepeatLimit--;
if(mMarqueeRepeatLimit <= 0){
if(null != marqueeCompleteListener){
marqueeCompleteListener.onMarqueeComplete();
}
return;
}
currentScrollX = -getWidth();
}

postDelayed(this, MARQUEE_RESTART_DELAY);
}

/**
*  开始滚动
*/
private void startScroll() {
isStop = false;
this.removeCallbacks(this);
this.invalidate();
currentScrollX = 0;
postDelayed(this, MARQUEE_DELAY);
}

/**
*  停止滚动
*/
private void stopScroll() {
isStop = true;
}

/**
*  从头开始滚动
*/
public void startFor0() {
currentScrollX = 0;
startScroll();
}
}