Android中跑马灯效果

<com.randy.test1.self.MarqueeText
android:id="@+id/btn1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ellipsize="marquee"
android:focusable="true"
android:focusableInTouchMode="true"
android:singleLine="true"
android:text="阿士大夫撒大声的发生的阿斯顿发送到发送到发送到发送到发送到发送到发撒的发生的发生的发生的发生撒旦法师打发斯蒂芬阿斯顿发生地方撒打发斯蒂芬" />

public class MarqueeText extends TextView{

public MarqueeText(Context context) {
super(context);
// TODO Auto-generated constructor stub
}

public MarqueeText(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}

public MarqueeText(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}

@Override
public boolean isFocused() {
// TODO Auto-generated method stub
return true;
}