使用Scroller时，为什么我的自定义视图不会滚动？

Question

我正在尝试使用Scroller移动自定义视图，但视图不会移动。任何人都可以帮我找到我的代码有什么问题吗？

public class CustomView extends View {

    private Scroller mScroller;

    public CustomView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mScroller = new Scroller(context);
    }

    public void smoothScrollTo(int destX, int destY) {
        int scrollX = getScrollX();
        int deltaX = destX - scrollX;

        int scrollY = getScrollY();
        int deltaY = destY - scrollY;

        mScroller.startScroll(scrollX, scrollY, deltaX, deltaY, 1000);

        invalidate();
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            int currX = mScroller.getCurrX();
            int currY = mScroller.getCurrY();

            Log.d("SCROLL", "currX = " + currX + ", currY = " + currY);

            scrollTo(currX, currY);
            postInvalidate();
        }
    }


public class MainActivity extends AppCompatActivity {

    private CustomView mCustomView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mCustomView = (CustomView)findViewById(R.id.custom_view);
    }

    public void onStart(View view) {
        mCustomView.smoothScrollTo(410, 200);
    }
}

布局XML文件：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.qihoo.scrollerdemo.MainActivity">

    <com.sample.scrollerdemo.CustomView
        android:id="@+id/custom_view"
        android:background="#ff0"
        android:layout_width="50dp"
        android:layout_height="50dp" />


    <Button
        android:onClick="onStart"
        android:text="start"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</FrameLayout>