TextView的跑马灯效果，还有焦点问题

TextView的跑马灯效果有2种做法：

1.直接设置TextView的xml属性，但需要焦点。

android:ellipsize="marquee"  android:marqueeRepeatLimit="marquee_forever"  

这个需要焦点，所以，自定义TextView，继承TextView，重写isFocused()方法：

1. 
       @Override  
2.     public boolean isFocused() {  
3.         return true;  
4.     }  

但该页面还有其他Thread线程，会干扰到TextView的跑马灯效果。

参考：http://blog.csdn.net/woshild666/article/details/5990692

2.另外一种是不需要获取焦点，推荐使用这种做法，

textview显示跑马灯效果，使用的是继承的方法onDraw不停地绘制 
优点： 
1.文字长短不限哦 
2.不用非得获取焦点哦

自定义的TextView：

public class MarqueeTextView extends TextView implements OnClickListener {public final static String TAG = MarqueeTextView.class.getSimpleName();private float textLength = 0f;// 文本长度private float viewWidth = 0f;private float step = 0f;// 文字的横坐标private float y = 0f;// 文字的纵坐标private float temp_view_plus_text_length = 0.0f;// 用于计算的临时变量private float temp_view_plus_two_text_length = 0.0f;// 用于计算的临时变量public boolean isStarting = false;// 是否开始滚动private Paint paint = null;// 绘图样式private String text = "";// 文本内容public MarqueeTextView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);// TODO Auto-generated constructor stub}public MarqueeTextView(Context context, AttributeSet attrs) {super(context, attrs);// TODO Auto-generated constructor stub}public MarqueeTextView(Context context) {super(context);// TODO Auto-generated constructor stub}/** * 初始化控件 */private void initView() {setOnClickListener(this);}/** *//** * 文本初始化，每次更改文本内容或者文本效果等之后都需要重新初始化一下 */public void init(WindowManager windowManager) {paint = getPaint();paint.setColor(Color.WHITE);text = getText().toString();textLength = paint.measureText(text);viewWidth = getWidth();if (viewWidth == 0) {if (windowManager != null) {Display display = windowManager.getDefaultDisplay();viewWidth = display.getWidth();}}step = textLength;temp_view_plus_text_length = viewWidth/2 + textLength;temp_view_plus_two_text_length = viewWidth/2 + textLength * 2;y = getTextSize() + getPaddingTop();}@Overridepublic Parcelable onSaveInstanceState() {Parcelable superState = super.onSaveInstanceState();SavedState ss = new SavedState(superState);ss.step = step;ss.isStarting = isStarting;return ss;}@Overridepublic void onRestoreInstanceState(Parcelable state) {if (!(state instanceof SavedState)) {super.onRestoreInstanceState(state);return;}SavedState ss = (SavedState) state;super.onRestoreInstanceState(ss.getSuperState());step = ss.step;isStarting = ss.isStarting;}public static class SavedState extends BaseSavedState {public boolean isStarting = false;public float step = 0.0f;SavedState(Parcelable superState) {super(superState);}@Overridepublic void writeToParcel(Parcel out, int flags) {super.writeToParcel(out, flags);out.writeBooleanArray(new boolean[] { isStarting });out.writeFloat(step);}public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {public SavedState[] newArray(int size) {return new SavedState[size];}@Overridepublic SavedState createFromParcel(Parcel in) {return new SavedState(in);}};private SavedState(Parcel in) {super(in);boolean[] b = null;in.readBooleanArray(b);if (b != null && b.length > 0)isStarting = b[0];step = in.readFloat();}}/** *//** * 开始滚动 */public void startScroll() {isStarting = true;invalidate();}/** *//** * 停止滚动 */public void stopScroll() {isStarting = false;invalidate();}@Overridepublic void onDraw(Canvas canvas) {canvas.drawText(text, temp_view_plus_text_length - step, y, paint);if (!isStarting) {return;}step += 1.5;if (step > temp_view_plus_two_text_length)step = textLength;invalidate();}@Overridepublic void onClick(View v) {if (isStarting)stopScroll();elsestartScroll();}}

参考：http://www.oschina.net/code/snippet_114929_12693

参考：http://chen2337.blog.163.com/blog/static/34039920201172945346977/

还有其它做法，有些是用的ScrollView，有些是调用

ScrollingMovementMethod方法