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ConstraintLayout: override baseline constraint in case the visibility of the dependent view was set to GONE

Is there a way to override the base constraint for the TextView in case the view's dependent visibility was set to GONE?

My layout code:

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

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TEST TITLE"
        android:textColor="@color/black"
        android:textSize="24sp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"/>

    <TextView
        android:id="@+id/subtitle1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="SUBTITLE 1"
        android:textSize="11sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/subtitle2"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/subtitleSpace"
        app:layout_constraintRight_toRightOf="parent"/>

    <android.support.v4.widget.Space
        android:id="@+id/subtitleSpace"
        android:layout_width="12dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toRightOf="@+id/subtitle1"
        app:layout_constraintRight_toLeftOf="@+id/subtitle2"/>

    <TextView
        android:id="@+id/subtitle2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:text="SUBTITLE 2"
        android:textSize="14sp"
        app:layout_constraintLeft_toRightOf="@+id/subtitleSpace"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/title"/>

</android.support.constraint.ConstraintLayout>

In this case, my layout looks like this: enter image description here

When I set the subtitle2

visibility of the TextView to GONE

, my layout looks like this: enter image description here

So I'm wondering if there is some kind of limitation that can rebuild the baseline in the absence of a dependent view.

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1 answer


Alternative margins can be specified for widgets GONE

(see Margins when connected to a GONE widget ), but I don't know of such an alternative for baselines.

One way to satisfy your requirement is to specify 0dp

invisible TextView

, which has the same characteristics GONE

TextView

that are located next to the same view. subtitle1

and subtitle2

will snap to the baseline of this new one TextView

. Even though the new TextView

one is not displayed on the screen and takes a zero width, it still maintains a baseline.

Now that it's subtitle2

done GONE

, it will subtitle1

move to the center, but keep its vertical position. (Note 0dp

and invisible

zero text is superfluous, but makes it clear that the widget does not appear.)



Here is the XML with these changes:

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

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TEST TITLE"
        android:textColor="#FF000000"
        android:textSize="24sp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    <TextView
        android:id="@+id/subtitle1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="SUBTITLE 1"
        android:textSize="11sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/viewForBaseline"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/subtitleSpace"
        app:layout_constraintRight_toRightOf="parent" />

    <android.support.v4.widget.Space
        android:id="@+id/subtitleSpace"
        android:layout_width="12dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toRightOf="@+id/subtitle1"
        app:layout_constraintRight_toLeftOf="@+id/subtitle2" />

    <TextView
        android:id="@+id/subtitle2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:text="SUBTITLE 2"
        android:textSize="14sp"
        android:visibility="gone"
        app:layout_constraintBaseline_toBaselineOf="@+id/viewForBaseline"
        app:layout_constraintLeft_toRightOf="@+id/subtitleSpace"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/title" />

    <TextView
        android:id="@+id/viewForBaseline"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:textSize="14sp"
        android:visibility="invisible"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/title" />

</android.support.constraint.ConstraintLayout>
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