The bottom of the scrollview is cropped when using ConstraintLayout

Question

I have a problem with ScrollViewinside ConstraintLayout( constraint-layout:1.0.0-beta3)

The contents of my ScrollView are not fully displayed.

Here is my layout:

<android.support.constraint.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/activity_test"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:id="@+id/header"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:background="#212121">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Constraint Layout"
            android:textSize="45sp"/>

    </LinearLayout>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toBottomOf="@+id/header"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="BUTTON"
                android:layout_marginTop="800dp"/>


        </LinearLayout>

    </ScrollView>

</android.support.constraint.ConstraintLayout>

And here is the result

As you can see, the button is not visible, and I reached the bottom of my ScrollView.

It seems to work well with LinearLayout with the layout below

<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_test"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:background="#212121">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Linear Layout"
            android:textSize="45sp"/>

    </LinearLayout>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="BUTTON"
                android:layout_marginTop="800dp"/>


        </LinearLayout>

    </ScrollView>

</LinearLayout>

And the result

With LinearLayout, the end of ScrollView is available.

Is there a bug with ConstraintLayout or am I doing something wrong?

Answer 1

How would I do this:

<android.support.constraint.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/activity_test"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/header"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="#212121"
        android:text="Constraint Layout"
        android:textSize="45sp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ScrollView
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:fillViewport="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/header">

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

            <Button
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom"
                android:text="BUTTON"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent" />

        </android.support.constraint.ConstraintLayout>

    </ScrollView>

</android.support.constraint.ConstraintLayout>

What gives:

A few things to keep in mind:

• linearlayout, textview .
• match_parent, , undefined. 0dp , .
• , 800dp. , , .
• scrollview - fillViewport , ,
• ConstraintLayout, . .

Answer 2

ScrollView match_parent . , .

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/header"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent">

. wrap_content , .