Android的滚动型，在可见的滚动 [英] Android ScrollView, scroll before visible

问题描述

我怎么可以设置滚动型滚动到x像素，之前它甚至显示？

how can I set scroll of scrollview to x pixels, before it's even shown?

在滚动型我有一些意见，而我知道，这将填补屏幕。我可以滚动，让说的第二种观点，使第一个视图时，活动开始是不可见的？

In ScrollView I have some Views and i know that it will fill screen. Can I scroll to let say second View, so that first View is not visible when activity is started?

现在我有某事像这样，但我认为这是不完美的，有时，我看到的第一视图，然后它的滚动到第二个

Now I have sth like this, but I think it's not perfect, sometimes, I see first View, and then it's scrolled to the second one

@Override
public void onGlobalLayout() {
    if (mHorizontalScrollView.getChildCount() > 0 && mHorizontalScrollView.getChildAt(0).getWidth() > mScreenWidth) {
            hsv.scrollTo(100, 0);
    }
}

编辑!!

第二次尝试是使用的http://developer.android.com/reference/android/view/ViewTreeObserver.On$p$pDrawListener.html代替<一个href="http://developer.android.com/reference/android/view/ViewTreeObserver.OnGlobalLayoutListener.html" rel="nofollow">http://developer.android.com/reference/android/view/ViewTreeObserver.OnGlobalLayoutListener.html 在在preDrawListener ，我们可以读到在这一点上，树中的所有意见进行了测量，并给出一个框架。客户端可以用这个来调整自己的滚动界限，甚至要求一个新的布局图发生之前。所以基本上在这一点上，我们应该调整滚动。所以，我创建了：

Second attempt was to use http://developer.android.com/reference/android/view/ViewTreeObserver.OnPreDrawListener.html instead of http://developer.android.com/reference/android/view/ViewTreeObserver.OnGlobalLayoutListener.html In OnPreDrawListener we can read that At this point, all views in the tree have been measured and given a frame. Clients can use this to adjust their scroll bounds or even to request a new layout before drawing occurs. so basically at this point we should adjust scrolling. So I created:

@Override
public boolean onPreDraw() {
    if (hsv.getChildCount() > 0 && hsv.getChildAt(0).getWidth() > mScreenWidth) {
        hsv.scrollTo(100, 0);
        return false;
    }
    return true;
}

但现在它从来没有为我工作。

but now it's never working for me.

推荐答案

我结合 onGlobalLayout 低于code。这不是那么伟大的使用技巧，但它仍然相当有效率。当我onGlobalLayout事件中，我检查，如果布局完成，那么，如果它的确定我使用下面的方法。

I combined onGlobalLayout with code below. It's not so great to use that hack but it still quite efficient. When I get onGlobalLayout event I check if layouts are done and then if it's ok I use method below.

// hsv - horizontal scroll view
private void forceShowColumn(final int column) {
    int scrollTo = childViewWidth * column;
    if (scrollTo == hsv.getScrollX()) {
        return;
    }
    hsv.scrollTo(scrollTo, 0);

    hsv.postDelayed(new Runnable() {

        @Override
        public void run() {
            forceShowColumn(column);
        }
    }, 10);
}

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