自动滚动TextView问题

Question

我需要实现文本行来显示从右到左的文本新闻。我使用了这个解决方案 - https://stackoverflow.com/a/8971920，并添加了一些消息堆栈和repeat times功能。因此，我的项目中有java和xml部分（链接到Gist：https://gist.github.com/artseld/4aac2a3b75bb5a741216）：

ScrollTextView.java

public class ScrollTextView extends TextView {

// scrolling feature
private Scroller mSlr;

// scroll speed
private float mScrollSpeed = 200f;

// the X offset when paused
private int mXPaused = 0;

// whether it's being paused
private boolean mPaused = true;

// messages
private LinkedList<Message> mMessages;

// current message
private String mMessage;
private int mRepeatTimes = 0;

/*
 * constructor
 */
public ScrollTextView(Context context) {
    this(context, null);
    // customize the TextView
    setSingleLine();
    setEllipsize(null);
    setVisibility(INVISIBLE);
}

/*
 * constructor
 */
public ScrollTextView(Context context, AttributeSet attrs) {
    this(context, attrs, android.R.attr.textViewStyle);
    // customize the TextView
    setSingleLine();
    setEllipsize(null);
    setVisibility(INVISIBLE);
}

/*
 * constructor
 */
public ScrollTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    // customize the TextView
    setSingleLine();
    setEllipsize(null);
    setVisibility(INVISIBLE);
}

/**
 * add message to messages pool
 * @param message String
 * @param repeatTimes int
 */
public void addMessage(String message, int repeatTimes) {
    if (mMessages == null) {
        mMessages = new LinkedList<>();
    }
    mMessages.add(new Message(message, repeatTimes));
    if (mMessage == null) {
        mMessage = message;
        mRepeatTimes = repeatTimes;
    }
    startScroll();
}

public void addMessage(String message) {
    addMessage(message, 1);
}

/**
 * begin to scroll the text from the original position
 */
public void startScroll() {
    if (mMessage == null)
        return;

    // set text
    if (getText() == null || !getText().equals(mMessage)) {
        setVisibility(INVISIBLE);
        setText(mMessage);
    }

    // begin from the very right side
    mXPaused = -1 * getWidth();
    // assume it's paused
    mPaused = true;
    resumeScroll();
}

/**
 * resume the scroll from the pausing point
 */
public void resumeScroll() {

    if (!mPaused)
        return;

    // Do not know why it would not scroll sometimes
    // if setHorizontallyScrolling is called in constructor.
    setHorizontallyScrolling(true);

    // use LinearInterpolator for steady scrolling
    mSlr = new Scroller(this.getContext(), new LinearInterpolator());
    setScroller(mSlr);

    int scrollingLen = calculateScrollingLen();
    int distance = scrollingLen - (getWidth() + mXPaused);
    int duration = (int) (1000f * distance / mScrollSpeed);

    setVisibility(VISIBLE);
    mSlr.startScroll(mXPaused, 0, distance, 0, duration);
    invalidate();
    mPaused = false;
}

/**
 * calculate the scrolling length of the text in pixel
 *
 * @return the scrolling length in pixels
 */
private int calculateScrollingLen() {
    TextPaint tp = getPaint();
    Rect rect = new Rect();
    String strTxt = getText().toString();
    tp.getTextBounds(strTxt, 0, strTxt.length(), rect);
    int scrollingLen = rect.width() + getWidth();
    rect = null;
    return scrollingLen;
}

/**
 * pause scrolling the text
 */
public void pauseScroll() {
    if (null == mSlr)
        return;

    if (mPaused)
        return;

    mPaused = true;

    // abortAnimation sets the current X to be the final X,
    // and sets isFinished to be true
    // so current position shall be saved
    mXPaused = mSlr.getCurrX();

    mSlr.abortAnimation();
}

@Override
 /*
 * override the computeScroll to restart scrolling when finished so as that
 * the text is scrolled forever
 */
public void computeScroll() {
    super.computeScroll();

    if (null == mSlr) return;

    if (mSlr.isFinished() && !mPaused) {
        if (--mRepeatTimes > 0) {
            startScroll();
            return;
        }
        if (mMessages != null && !mMessages.isEmpty()) {
            mMessage = mMessages.getFirst().getMessage();
            mRepeatTimes = mMessages.getFirst().getRepeatTimes();
            mMessages.removeFirst();
            startScroll();
            return;
        }
        mMessage = null;
        mRepeatTimes = 0;
    }
}

public float getScrollSpeed() {
    return mScrollSpeed;
}

public void setScrollSpeed(float scrollSpeed) {
    mScrollSpeed = scrollSpeed;
}

public boolean isPaused() {
    return mPaused;
}

class Message {

    private String mMessage;
    private int mRepeatTimes = 1;

    public Message(String message) {
        mMessage = message;
    }

    public Message(String message, int repeatTimes) {
        mMessage = message;
        mRepeatTimes = repeatTimes;
    }

    public String getMessage() {
        return mMessage;
    }

    public int getRepeatTimes() {
        return mRepeatTimes;
    }

}

}

MyActivity.java

public class MyActivity {

@Override
public void onCreate(Bundle savedInstanceState) {

  // ...

  final ScrollTextView scrollText = (ScrollTextView) findViewById(R.id.scroll_text);
  scrollText.addMessage("Message #1");
  scrollText.addMessage("Message #2");
  scrollText.addMessage("Message #3");

  // ...

}

}

my_activity_layout.xml

<com.mydomain.myproject.ScrollTextView
        android:id="@+id/scroll_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:singleLine="true" />

几乎所有工作都很好，但文本显示在textview的左侧几毫秒，然后才会按预期从右向左运行。

任何人都可以帮助我吗？非常感谢！