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。
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>