RelativeLayout中ScrollView设wrap_content与底部TextView间空白问题求助

Hey there! Let's tackle that frustrating gap between your ScrollView and the bottom TextView. The root issue here is how RelativeLayout handles the layout_above constraint—it forces the ScrollView to fill the entire vertical space between the s_text view and the bottom TextView, even when the ScrollView's content is short.

The best way to fix this is to switch to ConstraintLayout, which gives you far more control over how views behave in different content scenarios. Here's the adjusted layout that meets all your requirements:

<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/bottom_sheet"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/pub"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ellipsize="end"
        android:fontFamily="sans-serif-black"
        android:gravity="start|center"
        android:maxLines="1"
        android:padding="16dp"
        android:textIsSelectable="true"
        android:textStyle="italic"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/title_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:autoLink="web"
        android:ellipsize="end"
        android:fontFamily="sans-serif-black"
        android:gravity="left"
        android:maxLines="4"
        android:padding="16dp"
        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
        android:textStyle="bold"
        app:layout_constraintTop_toBottomOf="@id/pub" />

    <TextView
        android:id="@+id/s_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ellipsize="end"
        android:fontFamily="sans-serif-condensed"
        android:gravity="left|center"
        android:maxLines="2"
        android:padding="16dp"
        android:text=""
        android:textAppearance="@style/TextAppearance.AppCompat.Title"
        android:textSize="16sp"
        android:textStyle="normal"
        app:layout_constraintTop_toBottomOf="@id/title_text" />

    <ScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fillViewport="true"
        app:layout_constrainedHeight="true"
        app:layout_constraintBottom_toTopOf="@id/downloaded_file_name"
        app:layout_constraintTop_toBottomOf="@id/s_text">

        <TextView
            android:id="@+id/desc_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:autoLink="web"
            android:gravity="left"
            android:padding="16dp"
            android:scrollbars="vertical"
            android:textAppearance="@style/TextAppearance.AppCompat.Subhead"
            android:textColor="@color/colorPrimaryText"
            android:textSize="14sp" />
    </ScrollView>

    <TextView
        android:id="@+id/downloaded_file_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="end|bottom"
        android:padding="6dp"
        android:textIsSelectable="true"
        android:textSize="10sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@id/scrollView" />

</androidx.constraintlayout.widget.ConstraintLayout>

Key Changes Explained: #

• Switched to ConstraintLayout: This layout allows us to define flexible constraints that adapt to content size.
• app:layout_constrainedHeight="true" on ScrollView: This is the magic fix. When content is short, the ScrollView stays at wrap_content height, so the bottom TextView sits directly below it (no gap). When content is long, the ScrollView is constrained to fit between s_text and the bottom TextView, enabling scrolling without hiding the bottom element.
• Dual constraints on bottom TextView: It's anchored to both the parent bottom (so it stays at the bottom of the BottomSheet) and the ScrollView's bottom (so it follows the ScrollView when content is short).

Why Your Previous Attempts Didn't Work: #

• LinearLayout with weight: This forces the ScrollView to fill remaining space even when content is short, creating the gap. Without weight, long content pushes the bottom TextView off-screen.
• RelativeLayout layout_above: This stretches the ScrollView to fill the space to the bottom TextView regardless of content length, causing gaps for short text. Removing layout_above lets long content cover the bottom TextView.

内容的提问来源于stack exchange，提问作者itabdullah