ScrollView嵌套ConstraintLayout导致最后一项显示不全

原因：scrollView不受ConstraintLayout的约束布局影响

解决方法：

保持scrollview的宽高为0dp,设置其相对ConstraintLayout相对约束

<androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <ScrollView
            android:layout_width="0dp"
            android:layout_height="0dp"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"

            >
            <androidx.constraintlayout.widget.ConstraintLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

            </androidx.constraintlayout.widget.ConstraintLayout>
        </ScrollView>
    </androidx.constraintlayout.widget.ConstraintLayout>