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

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>

其他回答

参考资料:https://stackoverflow.com/a/6438240/2624806

接下来的工作要好得多。

mObservableScrollView.post(new Runnable() {
            public void run() { 
                mObservableScrollView.fullScroll([View_FOCUS][1]); 
            }
        });

你应该使你的TextView请求焦点:

    mTextView.requestFocus();

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);
}

如果有人正在寻找Kotlin版本,您可以使用扩展函数来实现这一点

fun ScrollView.scrollToChild(view: View, onScrolled: (() -> Unit)? = null) {
    view.requestFocus()
    val scrollBounds = Rect()
    getHitRect(scrollBounds)
    if (!view.getLocalVisibleRect(scrollBounds)) {
        findViewTreeLifecycleOwner()?.lifecycleScope?.launch(Dispatchers.Main) {
            smoothScrollTo(0, view.bottom - 40)
            onScrolled?.invoke()
        }
    }
}

有一个小回调让你在滚动之后做一些事情。

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>