Question

我正在进行自动水平滚动。所以我有15件物品。现在我想访问12项，所以我的索引是11.但我无法在索引发生时自动滚动它。

 horizontalScrollView.scrollTo(12, 0);

@Override
public void onPageSelected(int page) {
    for(int i = 0; i < holeTitle.length; i++) {
        if(i == page) {
            title[i].setTextColor(0xffffffff);
horizontalScrollView.scrollTo(12, 0);

        }
        else {
            title[i].setTextColor(0xffe0e0e0);

        }
    }

}

请专家看看。

Answer 1

DmRomantsov 's answer是滚动到第12个按钮的正确方法。但是，getLeft()和getRight()方法返回0，因为屏幕上尚未显示布局。现在计算布局父级和子级的宽度还为时过早。要实现它，您需要在onWindowFocusChanged内进行自动滚动。

@Override
public void onWindowFocusChanged(boolean hasFocus){
    super.onWindowFocusChanged(hasFocus);
    if(hasFocus){
        // do smoothScrollTo(...);
    }
}

但是，在Fragment中，上面的方法不起作用。我只是写了一个线索，了解这个概念。要在Fragment中具有相同的行为，您只需要执行Runnable，以便显示您的UI时间。然后，使用面向水平的LinearLayout执行此操作：

// Init variables
HorizontalScrollView mHS;
LinearLayout mLL;  

// onCreateView method
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.layout_container, container, false);

    // Find your views
    mHS = (HorizontalScrollView)view.findViewById(R.id.hscrollview);
    mLL = (LinearLayout)view.findViewById(R.id.hscrollview_container);  

    // Do a Runnable on the inflated view
    view.post(new Runnable() {
        @Override
        public void run() {
            Log.v("","Left position of 12th child = "+mLL.getChildAt(11).getLeft());
            mHS.smoothScrollTo(mLL.getChildAt(11).getLeft(), 0);
        }
    });
    return view;
}

Middle HorizontalScrollView：

你的问题是自动滚动到你的第12个孩子。但是，在下面的评论中，您要求我在HorizontalScrollView的中间自动滚动，我假设在每台设备上。您需要计算屏幕的宽度，容器的总宽度以及设备宽度中显示的子项数。这是一个简单的代码：

// Auto scroll to the middle (regardless of the width screen) view.post(new Runnable() { @Override public void run() { // Width of the screen DisplayMetrics metrics = getActivity().getResources() .getDisplayMetrics(); int widthScreen = metrics.widthPixels; Log.v("","Width screen total = " + widthScreen); // Width of the container (LinearLayout) int widthContainer = mLL.getWidth(); Log.v("","Width container total = " + widthContainer ); // Width of one child (Button) int widthChild = mLL.getChildAt(0).getWidth(); Log.v("","Width child = " + widthChild); // Nb children in screen int nbChildInScreen = widthScreen / widthChild; Log.v("","Width screen total / Width child = " + nbChildInScreen); // Width total of the space outside the screen / 2 (= left position) int positionLeftWidth = (widthContainer - (widthChild * nbChildInScreen))/2; Log.v("","Position left to the middle = " + positionLeftWidth); // Auto scroll to the middle mHS.smoothScrollTo(positionLeftWidth, 0); } }); /** * Your value might be resumed by: * * int positionLeftWidth = * ( mLL.getWidth() - ( mLL.getChildAt(0).getWidth() * * ( metrics.widthPixels / mLL.getChildAt(0).getWidth() ) ) ) / 2; * **/

具有所选值的中间HorizontalScrollView：

我有点误解了真正的要求。实际上，您想要自动滚动直到选定的子视图，并在屏幕中间显示此视图然后，我将最后int positionLeftWidth更改为所选视图相对于其父级的左侧位置，一个屏幕中包含的子级数，所选视图的半宽。因此，除positionLeftWidth：
外，代码与上述相同
// For example the chosen value is 7 // 7th Child position left int positionChildAt = mLL.getChildAt(6).getLeft(); // Width total of the auto-scroll (positionLeftWidth) int positionLeftWidth = positionChildAt - // position 7th child from left less ( ( nbChildInScreen // ( how many child contained in screen * widthChild ) / 2 ) // multiplied by their width ) divide by 2 + ( widthChild / 2 ); // plus ( the child view divide by 2 ) // Auto-scroll to the 7th child mHS.smoothScrollTo(positionLeftWidth, 0);

然后，无论getChildAt()方法中的值是什么，无论宽度屏幕如何，您都将在屏幕中间选择（在您的情况下）按钮。

Answer 2

尝试

horizontalScrollView.smoothScrollTo(horizontalScrollView.getChildAt(11).getRight(),0);

第一个patameter - X coord，第二个 - Y.
抵消：

public final void smoothScrollBy (int dx, int dy)

绝对：

public final void smoothScrollTo (int x, int y)

Answer 3

尝试horizontalScrollView.smoothScrollBy(12, 0);

Answer 4

试试这是工作代码。位置将是您要滚动的位置

  final HorizontalScrollView mHorizontalScrollView = (HorizontalScrollView) .findViewById(R.id.horizontalScrollView);
        mHorizontalScrollView.postDelayed(new Runnable() {
            @Override
            public void run() {
                mHorizontalScrollView.scrollTo(position, 0);
                mHorizontalScrollView.smoothScrollBy(1200, 0);
            }
        },100);

自动滚动到HorizontalScrollView

4 个答案:

自动滚动到Horizo​​ntalScrollView

4 个答案:

自动滚动到HorizontalScrollView