android - 使用合并标记时，复合 View 不可见

我有这个复合 View ArticleView，
当我将根LinearLayout替换为merge时，该 View 在我的测试设备或仿真器上均不可见。为什么会这样？
ArticleView.kt:

import android.content.Context
import android.util.AttributeSet
import android.view.LayoutInflater
import android.widget.LinearLayout
import com.kaf.hajjcompanion.R
import kotlinx.android.synthetic.main.article_view.view.*
import net.cachapa.expandablelayout.ExpandableLayout.State.EXPANDED

class ArticleView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : LinearLayout(context, attrs, defStyleAttr) {

    private val header by lazy { question_header }
    private val paragraph by lazy { paragraph_view }
    private val expandableParagraph by lazy { expandable_paragraph }

    init {
        inflate()
    }

    private fun inflate() {
        LayoutInflater.from(context).inflate(R.layout.article_view, this, true)

        header.setOnClickListener {
            expandableParagraph.toggle()
        }
        expandableParagraph.setOnExpansionUpdateListener { _, state ->
            header.setCompoundDrawablesRelativeWithIntrinsicBounds(
                0, 0,
                if (state == EXPANDED) R.drawable.ic_expand_less_white_24dp else R.drawable.ic_expand_more_white_24dp,
                0
            )
        }
    }

    fun render(viewState: ArticleViewState) {
        with(viewState) {
            header.setText(title)
            paragraph.text = paragraphText
        }
    }
}

article_view.xml:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
    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="@dimen/media_width"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/question_header"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/hajj_black"
        android:drawableEnd="@drawable/ic_expand_more_white_24dp"
        android:elevation="@dimen/default_elevation"
        android:padding="8dp"
        android:textAlignment="viewStart"
        android:textColor="@android:color/white"
        android:textSize="@dimen/entry_title_size"
        tools:text="@string/hajj_comp_how_to"
        />

    <net.cachapa.expandablelayout.ExpandableLayout
        android:id="@+id/expandable_paragraph"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:el_duration="500"
        app:el_expanded="false">

        <com.kaf.hajjcompanion.ui.commons.EmbeddedParagraphView
            android:id="@+id/paragraph_view"
            android:layout_width="match_parent"
            android:layout_height="@dimen/paragraph_height"/>
    </net.cachapa.expandablelayout.ExpandableLayout>

</LinearLayout>

在我的片段中:

    private fun renderState(state: SectionState) {
        when (state) {
            //..
            is SectionState.Article -> ArticleView(context!!).run {
                render(state.what)
                root.addView(this)
            }
            //..
        }
    }

分段:

<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="@dimen/media_width"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_gravity="center"
    android:scrollbars="none">

    <LinearLayout
        android:id="@+id/root"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:divider="@drawable/entries_divider"
        android:orientation="vertical"
        android:showDividers="middle"/>

</ScrollView>

请注意，我使用的不是RecyclerView，因为我处理的静态数据少于5个元素。

最佳答案

可能是因为您丢失了根参数:

android:layout_width="@dimen/media_width"
android:layout_height="match_parent"
android:orientation="vertical"

因此:

添加的ArticleViews的大小由封闭布局的generateDefaultLayoutParams()决定。

方向是LinearLayout的默认方向，如果没有记错的话，它是horizontal。