Android实现不依赖焦点和选中的TextView跑马灯

public class MarqueeTextView extends TextView {

  /** 是否停止滚动 */
  private boolean mStopMarquee;
  private String mText;
  private float mCoordinateX;
  private float mTextWidth;

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

  public void setText(String text) {
    this.mText = text;
    mTextWidth = getPaint().measureText(mText);
    if (mHandler.hasMessages(0))
      mHandler.removeMessages(0);
    mHandler.sendEmptyMessageDelayed(0, 2000);
  }

  @Override
  protected void onAttachedToWindow() {
    mStopMarquee = false;
    if (!StringUtils.isEmpty(mText))
      mHandler.sendEmptyMessageDelayed(0, 2000);
    super.onAttachedToWindow();
  }

  @Override
  protected void onDetachedFromWindow() {
    mStopMarquee = true;
    if (mHandler.hasMessages(0))
      mHandler.removeMessages(0);
    super.onDetachedFromWindow();
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (!StringUtils.isEmpty(mText))
      canvas.drawText(mText, mCoordinateX, 15, getPaint());
  }

  private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      switch (msg.what) {
      case 0:
        if (Math.abs(mCoordinateX) > (mTextWidth + 100)) {
          mCoordinateX = 0;
          invalidate();
          if (!mStopMarquee) {
            sendEmptyMessageDelayed(0, 2000);
          }
        } else {
          mCoordinateX -= 1;
          invalidate();
          if (!mStopMarquee) {
            sendEmptyMessageDelayed(0, 30);
          }
        }

        break;
      }
      super.handleMessage(msg);
    }
  };

}