Question

这是我的布局代码。当我单击可展开列表视图时，它不会展开。但是，如果我增加列表的高度，它会扩展。有没有办法通过代码动态增加列表的高度？我可以让它在我的布局中扩展。因为如果我增加高度，它只会在折叠列表中添加不必要的空白区域。

代码：

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.pocketcash.pocketcash.HomeActivity">

        <Switch
            android:id="@+id/detailedCashInfoSwitch"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:onClick="cashToggleSwitchClicked"
            android:text="Toggle Detailed Cash Info" />

        <Button
            android:id="@+id/addCashButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/expandableListView2"
            android:layout_centerHorizontal="true"
            android:onClick="launchAddCash"
            android:text="Add cash" />

        <Button
            android:id="@+id/addExpenditureButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/addCashButton"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="25dp"
            android:onClick="launchAddExpenditure"
            android:text="Add expenditure" />

        <TextView
            android:id="@+id/recentLogsText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:layout_below="@+id/addExpenditureButton"
            android:layout_marginTop="50dp"
            android:text="Recent Logs:"
            android:textAppearance="?android:attr/textAppearanceMedium" />

        <TextView
            android:id="@+id/logText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:layout_below="@+id/recentLogsText"
            android:layout_marginTop="0dp"
            android:text="Small Text"
            android:textAppearance="?android:attr/textAppearanceSmall" />

        <TextView
            android:id="@+id/recentViewAllText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/recentLogsText"
            android:layout_marginLeft="10dp"
            android:layout_toEndOf="@+id/recentLogsText"
            android:layout_toRightOf="@+id/recentLogsText"
            android:onClick="recentViewLogClicked"
            android:text="(view all)"
            android:textAppearance="?android:attr/textAppearanceMedium" />

        <TextView
            android:id="@+id/addViewAllText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/addCashButton"
            android:layout_centerHorizontal="true"
            android:onClick="addViewLogClicked"
            android:text="(view logs)"
            android:textAppearance="?android:attr/textAppearanceSmall" />

        <TextView
            android:id="@+id/expenseViewAllText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/addExpenditureButton"
            android:layout_centerHorizontal="true"
            android:onClick="expenseViewLogClicked"
            android:text="(view logs)"
            android:textAppearance="?android:attr/textAppearanceSmall" />

        <ImageView
            android:id="@+id/userImage"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:layout_below="@+id/detailedCashInfoSwitch"
            android:layout_marginTop="34dp"
            android:background="@drawable/default_user" />

        <TextView
            android:id="@+id/nameText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/userImage"
            android:layout_marginLeft="25dp"
            android:layout_toEndOf="@+id/userImage"
            android:layout_toRightOf="@+id/userImage"
            android:text="Name"
            android:textAppearance="?android:attr/textAppearanceLarge" />

        <TextView
            android:id="@+id/logoutText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/nameText"
            android:layout_alignStart="@+id/nameText"
            android:layout_below="@+id/nameText"
            android:clickable="true"
            android:onClick="logUserOut"
            android:text="logout"
            android:textAppearance="?android:attr/textAppearanceSmall" />

        <ImageButton
            android:id="@+id/settingsButton"
            android:layout_width="25dp"
            android:layout_height="25dp"
            android:layout_alignTop="@+id/nameText"
            android:layout_marginLeft="25dp"
            android:layout_toEndOf="@+id/nameText"
            android:layout_toRightOf="@+id/nameText"
            android:background="@drawable/settingsicon"
            android:onClick="launchSettingsActivity" />

        <fragment
            android:id="@+id/fragment_currentBalanceInfo"
            android:name="com.pocketcash.pocketcash.CurrentBalanceInfoFragment"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/userImage"
            android:layout_centerHorizontal="true"
            tools:layout="@layout/fragment_current_balance_info" />

        <ExpandableListView
            android:id="@+id/expandableListView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/fragment_currentBalanceInfo"
            android:layout_centerHorizontal="true"
            android:clickable="true" />

    </RelativeLayout>
</ScrollView>

Answer 1

作为http://docs.oasis-open.org/xliff/xliff-core/v2.0/os/schemas/modules/glossary.xsd（Google工程师使用UI工具包）在帖子中说

通过将宽度设置为wrap_content，您可以告诉ListView与其最宽的子项一样宽。因此，ListView必须测量其项目并获取必须在适配器上调用getView()的项目。这可能会发生几次，具体取决于布局传递的数量，父布局的行为等。

因此，如果您将ListView的布局宽度或布局高度设置为wrap_content，ListView会尝试测量附加到它的每个视图 - 这绝对不是什么你想要的。

请注意：避免始终为ListViews或GridViews或ExpandableListView设置wrap_content，有关详细信息，请参阅此Romain Guy说话关于listview的世界

将ExpandableListView设为match_parent

Answer 2

经过对此主题的大量研究后，我只能得出结论，像可扩展列表视图这样的可滚动对象不能在另一个可滚动视图中声明。但是我在运行时解决了这个问题，我稍微调整了一下我的java代码。

    expListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
        @Override
        public void onGroupExpand(int groupPosition) {
            int height = 0;
            for (int i = 0; i < expListView.getChildCount(); i++) {
                height += expListView.getChildAt(i).getMeasuredHeight();
                height += expListView.getDividerHeight();
            }
            expListView.getLayoutParams().height = (height+6)*10;
        }
    });

    // Listview Group collapsed listener
    expListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {

        @Override
        public void onGroupCollapse(int groupPosition) {
            expListView.getLayoutParams().height = 61;
        }
    });

这样我在窗口小部件展开或折叠时动态调整了窗口小部件的高度。它不是一个可靠的方法，它适用于命中和试用，所以我最终不得不将这个小部件移动到一个全新的活动。然而，这确实完美无瑕。但如果有人找到更好的答案，请分享。

Answer 3

我知道这个问题已经得到解答，但我有另一个解决方案可以适用于更多情况：我通过计算项目数来设置列表视图的初始高度，然后在崩溃/扩展组时更新此高度检索扩展/折叠组的子计数。以下是示例代码：

int item_size = 50;  // 50px
int sub_item_size = 40;  // 40px
expListView.getLayoutParams().height = item_size*myAdapter.getGroupCount();
expenseListView.setAdapter(myAdapter);
// ListView Group Expand Listener
expenseListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
    @Override
    public void onGroupExpand(int groupPosition) {
        int nb_children = myAdapter.getChildrenCount(groupPosition);
        expenseListView.getLayoutParams().height += sub_item_size*nb_children;
    }
});

// Listview Group collapsed listener
expenseListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {
    @Override
    public void onGroupCollapse(int groupPosition) {
        int nb_children = myAdapter.getChildrenCount(groupPosition);
        expenseListView.getLayoutParams().height -= sub_item_size*nb_children;
    }
});

Answer 4

通常，我们不能在Scrollview中使用ListView，GridView或ExpandableListView。如果需要，则必须为可扩展ListView赋予固定高度。

private void setListViewHeight(final ExpandableListView listView, final int groupPosition) {
    final ExpandableListAdapter listAdapter = (ExpandableListAdapter) listView.getExpandableListAdapter();
    int totalHeight = 0;
    // be careful with unspecified width measure spec, it will ignore all layout params and even
    // screen dimensions, so to get correct height, first get maximum width View can use and
    // call measure() this way
    final int desiredWidth = View.MeasureSpec.makeMeasureSpec(listView.getWidth(), View.MeasureSpec.EXACTLY);
    for (int i = 0; i < listAdapter.getGroupCount(); i++) {
        final View groupItem = listAdapter.getGroupView(i, false, null, listView);
        groupItem.measure(desiredWidth, View.MeasureSpec.UNSPECIFIED);

        totalHeight += groupItem.getMeasuredHeight();
        // count only expanded other groups or the clicked collapsed one
        if (((listView.isGroupExpanded(i)) && (i != groupPosition))
                || ((!listView.isGroupExpanded(i)) && (i == groupPosition))) {
            for (int j = 0, childrenNumber = listAdapter.getChildrenCount(i); j < childrenNumber; j++) {

                final View listItem = listAdapter.getChildView(i, j, j == childrenNumber - 1, null, listView);
                listItem.measure(desiredWidth, View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
                totalHeight += listItem.getMeasuredHeight();
            }
        }
    }
    final ViewGroup.LayoutParams params = listView.getLayoutParams();
    final int height = totalHeight
            + (listView.getDividerHeight() * (listAdapter.getGroupCount() - 1));
    params.height = height;
    listView.setLayoutParams(params);
    listView.requestLayout();
}

并在列表组点击上分配此方法：

expandableListView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
    @Override
    public boolean onGroupClick(final ExpandableListView expandableListView, final View view, final int groupPosition, final long id) {
        setListViewHeight(expandableListView, groupPosition);
        return false;
    }
});

重要：尽管此代码在大多数情况下都可以使用，但是当子列表项是带有android:layout_height="wrap_content"的TextView时，我遇到了一些问题，因此它们的高度取决于它们的宽度，这可能是相互关联的针对此问题：ViewGroup{TextView,...}.getMeasuredHeight gives wrong value is smaller than real height。请设法发表评论。

Answer 5

不幸的是，似乎没有一种方法可以使用wrap_content作为ExpandableListView的高度。而是设置一个固定的高度，android:nestedScrollingEnabled="true"对我有用。

Answer 6

我找到了一种更好的解决方案来实现这种现象，使用以下不太复杂且高效的 Kotlin 代码。

<块引用>

在此之前请记住一些要点：

<块引用>

使用固定的 height 父视图和子视图。
将父级和子级的高度提取到 dimens.xml 文件中。
在 ExpandableListView 中设置 divider='@null'、scrollbars="none"、groupIndicator="@null"（对于 customGroupIndicator，否则忽略）。
切勿使用 paddingVertical 包括 paddingTop 和 paddingBottom，对于具有动态高度的视图，将它们替换为 layoutMargins。

<块引用>

代码逻辑（对我来说，这个块是名为 initUi(uiObject) 的 ViewModel 函数的一部分）

//Here `ui` is a DataBinding object.
//You can use ViewBinding or simple Android findViewById as per your comfort.

val data: List<ModelClass> = listObject
val context = ui.root.context

ui.expandableList.apply {
    val mAdapter = MyExpandableListAdapter(data, context)
    setAdapter(mAdapter)

    //fetching parent height from dimens.xml
    val parentViewHeight = ceil(
        context.resources.getDimension(R.dimen.layout_menu_parent_height)
    ).toInt()

    //fetching child height from dimens.xml
    val childViewHeight = ceil(
        context.resources.getDimension(R.dimen.layout_menu_child_height)
    ).toInt()

    //Setting up the initial height of view when All parents are collapsed
    layoutParams.height = data.size * parentViewHeight

    setOnGroupExpandListener { groupPosition ->
        //Increasing the height for Expanded SubCategory
        layoutParams.height += mAdapter.getChildrenCount(groupPosition) * childViewHeight
    }

    setOnGroupCollapseListener { groupPosition ->
        //Decreasing the height for Collapsed SubCategory
        layoutParams.height -= mAdapter.getChildrenCount(groupPosition) * childViewHeight
    }
}

<块引用>

MyExpandableListAdapter.kt

class FragmentMenuExpandableListAdapter(
    val data: List<Data>, val context: Context
): BaseExpandableListAdapter() {
    //Declaring inflater Once can save a lot of CPU and RAM uses... 
    private val inflater = LayoutInflater.from(context)

    override fun getGroupCount(): Int = data.size

    override fun getChildrenCount(groupPosition: Int): Int = data[groupPosition].subcategories.size

    override fun getGroup(groupPosition: Int): Data = data[groupPosition]

    override fun getChild(groupPosition: Int, childPosition: Int) = data[groupPosition].subcategories[childPosition]

    override fun getGroupId(groupPosition: Int): Long = groupPosition.toLong()

    override fun getChildId(groupPosition: Int, childPosition: Int): Long = "$groupPosition$childPosition0".toLong()

    override fun hasStableIds(): Boolean = true

    override fun getGroupView(
        groupPosition: Int,
        isExpanded: Boolean,
        convertView: View?,
        parent: ViewGroup
    ): View {
        val binding = LayoutMenuParentBinding.inflate(inflater, parent, false)
        binding.apply {
            val temp = getGroup(groupPosition)
            title.text = temp.category_name

            //here I used a custom ImageView as GroupIndicator
            //So following code chunk is Optional
            if(temp.subcategories.isEmpty()) dropdownIcon.visibility = View.GONE
            else dropdownIcon.let { icon ->
                val view = parent as ExpandableListView
                icon.setImageResource(
                    if(view.isGroupExpanded(groupPosition)) {
                        icon.setOnClickListener { view.collapseGroup(groupPosition) }
                        R.drawable.ic_state_expanded
                    }
                    else {
                        icon.setOnClickListener {
                            view.expandGroup(groupPosition)
                        }
                        R.drawable.ic_state_collapsed
                    }
                )
            }

            root.setOnClickListener {
                TODO("Do on Parent click")
            }
        }
        return binding.root
    }

    override fun getChildView(
        groupPosition: Int,
        childPosition: Int,
        isLastChild: Boolean,
        convertView: View?,
        parent: ViewGroup?
    ): View {
        val binding = LayoutMenuChildBinding.inflate(
            inflater, parent, false
        ).apply {
            val temp = getChild(groupPosition, childPosition)
            title.text = temp.categoryName

            root.setOnClickListener {
                TODO("Do on Child click")
            }
        }
        return binding.root
    }

    override fun isChildSelectable(groupPosition: Int, childPosition: Int): Boolean = true
}

ExpandableListView可展开列表，当它的高度为wrap_content时，不会扩展，并且低于它

6 个答案: