CardView 内的 NestedScrollView 不滚动答案

【问题标题】：NestedScrollView inside CardView not scrollingCardView 内的 NestedScrollView 不滚动
【发布时间】：2021-03-13 18:05:41
【问题描述】：

在我的卡片视图布局中，我放置了一个约束布局，其中的 NestedScrollView 不滚动。我搜索了堆栈溢出，没有任何效果。这个 cardView 布局稍后会放在 RecyclerView 中，如果这很重要的话。下面我还推出了布局蓝图。只有一部分显示在回收器视图中，用户单击的浮动操作按钮视图正在展开。哪里出了问题？

<androidx.constraintlayout.widget.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_margin="10dp"
    android:layout_height="wrap_content">

    <androidx.cardview.widget.CardView
        android:id="@+id/main_cardview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">



        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/entire_card_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="@+id/main_cardview">

            <!--This is a ConstraintLayout for the fixed portion
                of the CardView. The elements
                that lie within the fixed portion of the CardView
                can be constrained to this layout.-->

            <androidx.constraintlayout.widget.ConstraintLayout
                android:id="@+id/fixed_container"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:background="@color/teal_700"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.0"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.0">

                <com.google.android.material.floatingactionbutton.FloatingActionButton
                    android:id="@+id/fab_expand"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginEnd="16dp"
                    android:background="#FFFFFF"
                    android:backgroundTint="@color/white"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintHorizontal_bias="0.954"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintVertical_bias="0.888"
                    app:srcCompat="@drawable/ic_baseline_expand_more_24" />
            </androidx.constraintlayout.widget.ConstraintLayout>

            <androidx.constraintlayout.widget.ConstraintLayout
                android:id="@+id/hidden_layout"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:visibility="gone"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintTop_toBottomOf="@id/fixed_container"
                tools:visibility="visible">

                <androidx.core.widget.NestedScrollView
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:fillViewport="true"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintHorizontal_bias="0.0"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toBottomOf="parent">

                    <com.google.android.material.textview.MaterialTextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/lorem_ipsum_long" />


                </androidx.core.widget.NestedScrollView>
            </androidx.constraintlayout.widget.ConstraintLayout>

        </androidx.constraintlayout.widget.ConstraintLayout>


    </androidx.cardview.widget.CardView>


</androidx.constraintlayout.widget.ConstraintLayout>

布局蓝图：

【问题讨论】：

为什么会有很多约束布局？能分享一下你的视图设计吗？
@Priyanka 当然，我已经更新了我的帖子。
你的代码运行良好，我现在测试了

标签： android android-layout android-constraintlayout

【解决方案1】：

您的代码运行良好。稍微修改了一下。请检查一下。

<androidx.constraintlayout.widget.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_margin="10dp"
android:layout_height="wrap_content">

<androidx.cardview.widget.CardView
    android:id="@+id/main_cardview"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent">



    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/entire_card_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/main_cardview">

        <!--This is a ConstraintLayout for the fixed portion
            of the CardView. The elements
            that lie within the fixed portion of the CardView
            can be constrained to this layout.-->

        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/fixed_container"
            android:layout_width="match_parent"
            android:layout_height="200dp"
            android:background="@color/teal_700"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.0">

            <com.google.android.material.floatingactionbutton.FloatingActionButton
                android:id="@+id/fab_expand"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="16dp"
                android:background="#FFFFFF"
                android:backgroundTint="@color/white"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.954"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_bias="0.888"
                app:srcCompat="@drawable/ic_launcher_foreground"
                android:layout_marginRight="16dp"
                tools:ignore="VectorDrawableCompat" />
        </androidx.constraintlayout.widget.ConstraintLayout>

        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/hidden_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintTop_toBottomOf="@id/fixed_container"
            tools:visibility="visible">

            <androidx.core.widget.NestedScrollView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fillViewport="true"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="parent">
                    <com.google.android.material.textview.MaterialTextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="@string/lorem_ipsum_long"
                        android:layout_marginBottom="16dp"/>


            </androidx.core.widget.NestedScrollView>
        </androidx.constraintlayout.widget.ConstraintLayout>

    </androidx.constraintlayout.widget.ConstraintLayout>


</androidx.cardview.widget.CardView>


</androidx.constraintlayout.widget.ConstraintLayout>

【讨论】：