ImageView layout BUG in the androidx.constraintlayout:constraintlayout:2.1.0

I’m using Android Studio 2020.3.1 patch 3 and the ConstraintLayout for displaying two rows UI.

Here is the expected UI latyout:

-------------------------------------------------------------------------
first_row_text_view  |   first_row_edit_text   |   first_row_image_view
-------------------------------------------------------------------------
second_row_text_view |   second_row_image_view |   second_row_switch
-------------------------------------------------------------------------

But the second_row_image_view is not at the expected position when using the “test.xml”, it is floating on the top of the first_row_edit_text.

Here is the build.gradle settings:

dependencies {
...
implementation 'androidx.constraintlayout:constraintlayout:2.1.0'
...
}

Here is the test layout: test.xml

<?xml version="1.0" encoding="utf-8"?>
<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_height="match_parent">
    
    <TextView
        android:id="@+id/first_row_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/first_row_edit_text"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintBaseline_toBaselineOf="@id/first_row_text_view"
        app:layout_constraintEnd_toStartOf="@id/first_row_image_view"
        app:layout_constraintStart_toEndOf="@id/barrier_left_right"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/first_row_image_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginHorizontal="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@id/first_row_edit_text"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/second_row_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/barrier_first_row" />

    <ImageView
        android:id="@+id/second_row_image_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintBaseline_toBaselineOf="@id/second_row_text_view"
        app:layout_constraintEnd_toStartOf="@id/second_row_switch"
        app:layout_constraintStart_toEndOf="@id/barrier_left_right"
        app:layout_constraintTop_toBottomOf="@id/barrier_first_row"/>

    <Switch
        android:id="@+id/second_row_switch"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBaseline_toBaselineOf="@id/second_row_text_view"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@id/second_row_image_view"
        app:layout_constraintTop_toBottomOf="@id/barrier_first_row" />

    <androidx.constraintlayout.widget.Barrier
        android:id="@+id/barrier_left_right"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="end"
        app:constraint_referenced_ids="first_row_text_view,second_row_text_view"
        tools:layout_editor_absoluteX="410dp"
        tools:layout_editor_absoluteY="1dp" />

    <androidx.constraintlayout.widget.Barrier
        android:id="@+id/barrier_first_row"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="bottom"
        app:constraint_referenced_ids="first_row_text_view,first_row_edit_text,first_row_image_view" />

</androidx.constraintlayout.widget.ConstraintLayout>

But If I change the ImageView (second_row_image_view) to EditText with the same name, the ConstraintLayout can display the EditText at the right place.

<EditText
    android:id="@+id/second_row_image_view"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    app:layout_constraintBaseline_toBaselineOf="@id/second_row_text_view"
    app:layout_constraintEnd_toStartOf="@id/second_row_switch"
    app:layout_constraintStart_toEndOf="@id/barrier_left_right"
    app:layout_constraintTop_toBottomOf="@id/barrier_first_row"/>

Is it a BUG or something else?

Thanks.

For testing:

You can copy the test.xml to the res/layout, open the test.xml in the “Code” view, and then click on the “second_row_image_view”, finally, switch to the “Design” view, you can also find out that the second_row_image_view is floating on the top of the first_row_edit_text.

Answer

It is because of app:layout_constraintBaseline_toBaselineOf. Baseline is a property of text based views. ImageViews don’t have a baseline while EditTexts do