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
你可以像这样使用ObjectAnimator:
ObjectAnimator.ofInt(yourScrollView, "scrollY", yourView.getTop()).setDuration(1500).start();
其他回答
你应该使你的TextView请求焦点:
mTextView.requestFocus();
垂直滚动,适合窗体。答案是基于艾哈迈迪巴洛赫水平卷轴。
private final void focusOnView(final HorizontalScrollView scroll, final View view) {
new Handler().post(new Runnable() {
@Override
public void run() {
int top = view.getTop();
int bottom = view.getBottom();
int sHeight = scroll.getHeight();
scroll.smoothScrollTo(0, ((top + bottom - sHeight) / 2));
}
});
}
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));
...
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);
}
我的EditText在ScrollView中嵌套了几个层,而ScrollView本身并不是布局的根视图。因为getTop()和getBottom()似乎在报告它所包含的视图中的坐标,所以我让它通过迭代EditText的父节点来计算从ScrollView顶部到EditText顶部的距离。
// Scroll the view so that the touched editText is near the top of the scroll view
new Thread(new Runnable()
{
@Override
public
void run ()
{
// Make it feel like a two step process
Utils.sleep(333);
// Determine where to set the scroll-to to by measuring the distance from the top of the scroll view
// to the control to focus on by summing the "top" position of each view in the hierarchy.
int yDistanceToControlsView = 0;
View parentView = (View) m_editTextControl.getParent();
while (true)
{
if (parentView.equals(scrollView))
{
break;
}
yDistanceToControlsView += parentView.getTop();
parentView = (View) parentView.getParent();
}
// Compute the final position value for the top and bottom of the control in the scroll view.
final int topInScrollView = yDistanceToControlsView + m_editTextControl.getTop();
final int bottomInScrollView = yDistanceToControlsView + m_editTextControl.getBottom();
// Post the scroll action to happen on the scrollView with the UI thread.
scrollView.post(new Runnable()
{
@Override
public void run()
{
int height =m_editTextControl.getHeight();
scrollView.smoothScrollTo(0, ((topInScrollView + bottomInScrollView) / 2) - height);
m_editTextControl.requestFocus();
}
});
}
}).start();