如何实现TextView纵向滚动？纵向跑马灯效果

按照网上的方法 在textview外面嵌套了一个ScrollView 并设置
android:scrollbars="vertical"
android:fillViewport="true"
android:layout_weight="1.0"
属性之后可以手动实现滚动效果但并不是自动的，求大神指点啊！

网上搜到的代码，自定义view
public class AutoScrollText extends TextView {

public final static String TAG = AutoScrollText.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 AutoScrollText(Context context) {
    super(context);
}

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

public AutoScrollText(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}


public void init(WindowManager windowManager,int color) {
    paint = getPaint();
    paint.setColor(color);
    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 + textLength;
    temp_view_plus_two_text_length = viewWidth + textLength * 2;
    y = getTextSize() + getPaddingTop();
}

@Override
public Parcelable onSaveInstanceState() {
    Parcelable superState = super.onSaveInstanceState();
    SavedState ss = new SavedState(superState);

    ss.step = step;
    ss.isStarting = isStarting;

    return ss;

}

@Override
public 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);
    }

    @Override
    public 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];
        }

        @Override
        public 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();
    }
}


public void startScroll() {
    isStarting = true;
    invalidate();
}


public void stopScroll() {
    isStarting = false;
    invalidate();
}


@Override
public void onDraw(Canvas canvas) {
    canvas.drawText(text, temp_view_plus_text_length - step, y, paint);
    if (!isStarting) {
        return;
    }
    step += 0.5;//0.5为文字滚动速度。
    if (step > temp_view_plus_two_text_length)
        step = textLength;
    invalidate();

}

}

调用：
void scroll3(View view){
AutoScrollText auto=(AutoScrollText)view.findViewById(R.id.autoTxt);
auto.setText(“aaaaaaaaaaa”);
auto.init(getActivity().getWindowManager(),0xFFFF0000);
auto.startScroll();

}

    本人亲测可用

你可以设置个计时器，每过多长时间调用一下ScrollView 滚动方法