我有一个很长的带有滚动视图的活动。它是一个包含用户必须填写的各种字段的表单。我在表单的中间有一个复选框,当用户选中它时,我想滚动到视图的特定部分。是否有办法以编程方式滚动到EditText对象(或任何其他视图对象)?

此外,我知道这是可能的使用X和Y坐标,但我想避免这样做,因为形式可能会从用户到用户的变化。


当前回答

如果sclmain是你的NestedScrollView,那么使用以下方法:

scrlMain.post(new Runnable() {
    @Override
    public void run() {
        scrlMain.fullScroll(View.FOCUS_UP);
    }
});

其他回答

我认为我已经找到了更优雅、更不容易出错的解决方案

ScrollView.requestChildRectangleOnScreen

它不涉及数学运算,与其他提出的解决方案相反,它将正确地处理上下滚动。

/**
 * Will scroll the {@code scrollView} to make {@code viewToScroll} visible
 * 
 * @param scrollView parent of {@code scrollableContent}
 * @param scrollableContent a child of {@code scrollView} whitch holds the scrollable content (fills the viewport).
 * @param viewToScroll a child of {@code scrollableContent} to whitch will scroll the the {@code scrollView}
 */
void scrollToView(ScrollView scrollView, ViewGroup scrollableContent, View viewToScroll) {
    Rect viewToScrollRect = new Rect(); //coordinates to scroll to
    viewToScroll.getHitRect(viewToScrollRect); //fills viewToScrollRect with coordinates of viewToScroll relative to its parent (LinearLayout) 
    scrollView.requestChildRectangleOnScreen(scrollableContent, viewToScrollRect, false); //ScrollView will make sure, the given viewToScrollRect is visible
}

如果ScrollView正在被更改,那么将它封装到postDelayed中以使其更加可靠是个好主意

/**
 * Will scroll the {@code scrollView} to make {@code viewToScroll} visible
 * 
 * @param scrollView parent of {@code scrollableContent}
 * @param scrollableContent a child of {@code scrollView} whitch holds the scrollable content (fills the viewport).
 * @param viewToScroll a child of {@code scrollableContent} to whitch will scroll the the {@code scrollView}
 */
private void scrollToView(final ScrollView scrollView, final ViewGroup scrollableContent, final View viewToScroll) {
    long delay = 100; //delay to let finish with possible modifications to ScrollView
    scrollView.postDelayed(new Runnable() {
        public void run() {
            Rect viewToScrollRect = new Rect(); //coordinates to scroll to
            viewToScroll.getHitRect(viewToScrollRect); //fills viewToScrollRect with coordinates of viewToScroll relative to its parent (LinearLayout) 
            scrollView.requestChildRectangleOnScreen(scrollableContent, viewToScrollRect, false); //ScrollView will make sure, the given viewToScrollRect is visible
        }
    }, delay);
}

如果sclmain是你的NestedScrollView,那么使用以下方法:

scrlMain.post(new Runnable() {
    @Override
    public void run() {
        scrlMain.fullScroll(View.FOCUS_UP);
    }
});

另一种说法是:

scrollView.postDelayed(new Runnable()
{
    @Override
    public void run()
    {
        scrollView.smoothScrollTo(0, img_transparent.getTop());
    }
}, 200);

或者可以使用post()方法。

Sherif elKhatib的答案可以大大改进,如果你想将视图滚动到滚动视图的中心。这个可重用的方法平滑地将视图滚动到HorizontalScrollView的可见中心。

private final void focusOnView(final HorizontalScrollView scroll, final View view) {
    new Handler().post(new Runnable() {
        @Override
        public void run() {
            int vLeft = view.getLeft();
            int vRight = view.getRight();
            int sWidth = scroll.getWidth();
            scroll.smoothScrollTo(((vLeft + vRight - sWidth) / 2), 0);
        }
    });
}

对于垂直ScrollView的使用

...
int vTop = view.getTop();
int vBottom = view.getBottom();
int sHeight = scroll.getBottom();
scroll.smoothScrollTo(0, ((vTop + vBottom - sHeight) / 2));
...

在我看来,滚动到给定矩形的最好方法是通过视图。requestRectangleOnScreen(矩形、布尔值)。你应该在你想要滚动到的视图上调用它,并传递一个你想要在屏幕上可见的局部矩形。第二个参数在平滑滚动时为假,在即时滚动时为真。

final Rect rect = new Rect(0, 0, view.getWidth(), view.getHeight());
view.requestRectangleOnScreen(rect, false);