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

这对我来说很管用:

  targetView.getParent().requestChildFocus(targetView,targetView);

RequestChildFocus(查看子视图,查看焦点)

child -这个ViewParent的想要聚焦的子对象。该视图将包含聚焦视图。它并不一定是真正有焦点的观点。

focused -实际上具有焦点的child的后代视图

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);
}

将postDelayed添加到视图中,这样getTop()就不会返回0。

binding.scrollViewLogin.postDelayed({
            val scrollTo = binding.textInputLayoutFirstName.top
            binding.scrollViewLogin.isSmoothScrollingEnabled = true
            binding.scrollViewLogin.smoothScrollTo(0, scrollTo)
     }, 400
) 

还要确保视图是scrollView的直接子视图,否则你会得到getTop()为零。示例:嵌入在TextInputLayout中的edittext的getTop()将返回0。在这种情况下,我们需要计算TextInputLayout的getTop()它是ScrollView的直接子。

<ScrollView>
    <TextInputLayout>
        <EditText/>
    </TextInputLayout>
</ScrollView>

根据Sherif的回答,以下内容最适合我的用例。值得注意的变化是getTop()而不是getBottom()和smoothScrollTo()而不是scrollTo()。

    private void scrollToView(final View view){
        final ScrollView scrollView = findViewById(R.id.bookmarksScrollView);
        if(scrollView == null) return;

        scrollView.post(new Runnable() {
            @Override
            public void run() {
                scrollView.smoothScrollTo(0, view.getTop());
            }
        });
    }

我基于WarrenFaith的答案做了一个小工具方法,这段代码也考虑了视图是否已经在滚动视图中可见,不需要滚动。

public static void scrollToView(final ScrollView scrollView, final View view) {

    // View needs a focus
    view.requestFocus();

    // Determine if scroll needs to happen
    final Rect scrollBounds = new Rect();
    scrollView.getHitRect(scrollBounds);
    if (!view.getLocalVisibleRect(scrollBounds)) {
        new Handler().post(new Runnable() {
            @Override
            public void run() {
                scrollView.smoothScrollTo(0, view.getBottom());
            }
        });
    } 
}
private final void focusOnView(){
    yourScrollView.post(new Runnable() {
        @Override
        public void run() {
            yourScrollView.scrollTo(0, yourEditText.getBottom());
        }
    });
}