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

我知道这可能太迟了,没有更好的答案,但理想的完美解决方案必须是一个像定位器这样的系统。我的意思是,当系统为一个编辑器字段进行定位时,它将该字段放置在键盘上方,因此作为UI/UX规则,这是完美的。

What below code makes is the Android way positioning smoothly. First of all we keep the current scroll point as a reference point. Second thing is to find the best positioning scroll point for an editor, to do this we scroll to top, and then request the editor fields to make the ScrollView component to do the best positioning. Gatcha! We've learned the best position. Now, what we'll do is scroll smoothly from the previous point to the point we've found newly. If you want you may omit smooth scrolling by using scrollTo instead of smoothScrollTo only.

注意:主容器ScrollView是一个名为scrollViewSignup的成员字段,因为我的示例是一个注册屏幕,正如您可能发现的那样。

view.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(final View view, boolean b) {
            if (b) {
                scrollViewSignup.post(new Runnable() {
                    @Override
                    public void run() {
                        int scrollY = scrollViewSignup.getScrollY();
                        scrollViewSignup.scrollTo(0, 0);
                        final Rect rect = new Rect(0, 0, view.getWidth(), view.getHeight());
                        view.requestRectangleOnScreen(rect, true);

                        int new_scrollY = scrollViewSignup.getScrollY();
                        scrollViewSignup.scrollTo(0, scrollY);
                        scrollViewSignup.smoothScrollTo(0, new_scrollY);
                    }
                });
            }
        }
    });

如果您希望将此块用于所有EditText实例,并将其与屏幕代码快速集成。您可以简单地像下面这样创建一个遍历器。为此,我已经使主OnFocusChangeListener一个名为focusChangeListenerToScrollEditor的成员字段,并在onCreate期间调用它如下所示。

traverseEditTextChildren(scrollViewSignup, focusChangeListenerToScrollEditor);

方法实现如下所示。

private void traverseEditTextChildren(ViewGroup viewGroup, View.OnFocusChangeListener focusChangeListenerToScrollEditor) {
    int childCount = viewGroup.getChildCount();
    for (int i = 0; i < childCount; i++) {
        View view = viewGroup.getChildAt(i);
        if (view instanceof EditText)
        {
            ((EditText) view).setOnFocusChangeListener(focusChangeListenerToScrollEditor);
        }
        else if (view instanceof ViewGroup)
        {
            traverseEditTextChildren((ViewGroup) view, focusChangeListenerToScrollEditor);
        }
    }
}

因此,我们在这里所做的是让所有EditText实例的子实例在焦点处调用侦听器。

为了达到这个解决方案,我检查了这里所有的解决方案,并生成了一个更好的UI/UX结果的新解决方案。

Many thanks to all other answers inspiring me much.

其他回答

问:有没有一种方法,以编程方式滚动滚动视图到特定的编辑文本?

答:嵌套滚动视图在recyclerview最后位置添加记录数据。

adapter.notifyDataSetChanged();
nested_scroll.setScrollY(more Detail Recycler.getBottom());

是否有一种方法以编程方式滚动滚动视图到特定的编辑文本?

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();

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);
    }
});

如果你想在打开软键盘时滚动到一个视图,那么这可能有点棘手。 到目前为止,我得到的最好的解决方案是使用嵌套回调和requestRectangleOnScreen方法的组合。

首先,你需要设置inset回调:

fun View.doOnApplyWindowInsetsInRoot(block: (View, WindowInsetsCompat, Rect) -> Unit) {
    val initialPadding = recordInitialPaddingForView(this)
    val root = getRootForView(this)
    ViewCompat.setOnApplyWindowInsetsListener(root) { v, insets ->
        block(v, insets, initialPadding)
        insets
    }
    requestApplyInsetsWhenAttached()
}

fun View.requestApplyInsetsWhenAttached() {
    if (isAttachedToWindow) {
        requestApplyInsets()
    } else {
        addOnAttachStateChangeListener(object : View.OnAttachStateChangeListener {
            override fun onViewAttachedToWindow(v: View) {
                v.removeOnAttachStateChangeListener(this)
                v.requestApplyInsets()
            }

            override fun onViewDetachedFromWindow(v: View) = Unit
        })
    }
}

我们在根视图上设置了一个回调来确保我们被调用。插图可能在我们的视图接收到它们之前就被消耗掉了,所以我们必须在这里做额外的工作。

现在很简单了:

doOnApplyWindowInsetsInRoot { _, _, _ ->
    post {
        if (viewInQuestion.hasFocus()) {
            requestRectangleOnScreen(Rect(0, 0, width, height))
        }
    }
}

你可以摆脱焦点检查。它的存在是为了限制requestRectangleOnScreen的调用数量。我使用post在可滚动的父滚动到聚焦视图后运行一个操作。