java - RecyclerView Item 不包裹 ListView 的高度

Question

所以我有这个 Activity ，如下所示:

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.jonas.trainingslog1.WorkoutDataActivity">


        <android.support.constraint.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <android.support.constraint.ConstraintLayout
                ...
            </android.support.constraint.ConstraintLayout>

            <android.support.v7.widget.RecyclerView
                android:id="@+id/recyclerView"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layout_constraintTop_toBottomOf="@+id/layout">

            </android.support.v7.widget.RecyclerView>


        </android.support.constraint.ConstraintLayout>

如您所见，该 Activity 有一个 RecyclerView，其项目如下所示:

<android.support.constraint.ConstraintLayout 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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_marginTop="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp">


<ListView
    android:id="@+id/lst"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">


</ListView>

<Button
    android:layout_width="match_parent"
    android:layout_height="30dp"
    app:layout_constraintTop_toBottomOf="@+id/lst"/>

ListView的高度在 RecyclerView项目的高度只能与其内容一样高，因此我将其设置为 wrap_content 。问题是，只有当我设置 RecyclerView 的高度时，这才有效。项目布局为match_parent ，一旦我将其更改为 wrap_content ListView 仅显示一项。我怎么也离不开RecyclerView的高度项目为match_parent因为 RecyclerView 的每一项有大量未使用的空间。

谁知道如何解决这个问题？我不明白 xml 文件的这种行为。我非常感谢帮助。

Answer 1

将其添加到您的 ListView 中...动态设置 ListView 的高度

public static void setListViewHeightBasedOnChildren(final ListView listView) {
listView.post(new Runnable() {
    @Override
    public void run() {
        ListAdapter listAdapter = listView.getAdapter();
        if (listAdapter == null) {
            return;
        }
        int totalHeight = listView.getPaddingTop() + listView.getPaddingBottom();
        int listWidth = listView.getMeasuredWidth();
        for (int i = 0; i < listAdapter.getCount(); i++) {
            View listItem = listAdapter.getView(i, null, listView);
            listItem.measure(
                    View.MeasureSpec.makeMeasureSpec(listWidth, View.MeasureSpec.EXACTLY),
                    View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));


            totalHeight += listItem.getMeasuredHeight();
            Log.d("listItemHeight " + listItem.getMeasuredHeight(), "********");
        }

        Log.d("totalHeight " + totalHeight, "********");

        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = (totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1)));
        listView.setLayoutParams(params);
        listView.requestLayout();

    }
});
}

将其添加到您的 recyclerview 适配器