可以一直滚动的跑马灯

 1 public class AutoScrollTextView extends TextView implements Runnable {
 2     private int currentScrollX;// 当前滚动的位置
 3     private boolean isStop = false;
 4     private int textWidth;
 5     private boolean isMeasure = false;
 6 
 7     public AutoScrollTextView(Context context) {
 8         super(context);
 9     }
10 
11     public AutoScrollTextView(Context context, AttributeSet attrs) {
12         super(context, attrs);
13     }
14 
15     public AutoScrollTextView(Context context, AttributeSet attrs, int defStyle) {
16         super(context, attrs, defStyle);
17     }
18 
19     @Override
20     protected void onDraw(Canvas canvas) {
21         super.onDraw(canvas);
22         if (!isMeasure) {// 文字宽度只需获取一次就可以了
23             getTextWidth();
24             isMeasure = true;
25         }
26     }
27 
28     /**
29      * 获取文字宽度
30      */
31     private void getTextWidth() {
32         Paint paint = this.getPaint();
33         String str = this.getText().toString();
34         textWidth = (int) paint.measureText(str);
35     }
36 
37     @Override
38     public void run() {
39         currentScrollX -= 1;// 滚动速度
40         scrollTo(currentScrollX, 0);
41         if (isStop) {
42             return;
43         }
44         if (getScrollX() <= -(this.getWidth())) {
45             scrollTo(textWidth, 0);
46             currentScrollX = textWidth;
47         }
48         postDelayed(this, 5);
49     }
50 
51     // 开始滚动
52     public void startScroll() {
53         isStop = false;
54         this.removeCallbacks(this);
55         post(this);
56     }
57 
58     // 停止滚动
59     public void stopScroll() {
60         isStop = true;
61     }
62 
63     // 从头开始滚动
64     public void startFor0() {
65         currentScrollX = 0;
66         startScroll();
67     }
68 }