如何在 ConstraintLayout 中水平放置两个视图中心？

Question

在 ConstraintLayout 中，我需要将两个视图假设为一个组，并将该组中心水平放置在父级中，如下图所示：

这是我的 xml 代码：

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp">

    <TextView
        android:id="@+id/view_a"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_orange_dark"
        android:gravity="center"
        android:text="View A"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintEnd_toStartOf="@id/view_b"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/view_b"
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_red_light"
        android:gravity="center"
        android:text="View B"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@id/view_a"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

我已经看过但它在两个视图具有相同宽度时有效。我的视图宽度不同，所以 Guideline 不起作用！

我该怎么做？

Answer 1

You can achive your view using guidline and barrier.

Take vertical guildline in center. After left textview start constraint to barrier1 and right textview end constraint to barrier2.

    <?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp">

    <TextView
        android:id="@+id/view_a"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/_50sdp"
        android:layout_marginEnd="@dimen/_5sdp"
        android:background="@android:color/holo_orange_dark"
        android:gravity="center"
        android:text="View A"
        app:layout_constraintStart_toEndOf="@+id/barrier"
        app:layout_constraintEnd_toStartOf="@+id/guideline"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.constraintlayout.widget.Barrier
        android:id="@+id/barrier"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="left"
        app:constraint_referenced_ids="view_a" />

    <TextView
        android:id="@+id/view_b"
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_red_light"
        android:gravity="center"
        android:layout_marginStart="@dimen/_5sdp"
        android:text="View B"
        app:layout_constraintEnd_toStartOf="@+id/barrier2"
        app:layout_constraintHorizontal_chainStyle="spread"
        app:layout_constraintBottom_toBottomOf="@id/view_a"
        app:layout_constraintStart_toEndOf="@+id/guideline"
        app:layout_constraintTop_toTopOf="@id/view_a" />

    <androidx.constraintlayout.widget.Barrier
        android:id="@+id/barrier2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="right"
        app:constraint_referenced_ids="view_b" />

    <android.support.constraint.Guideline
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/guideline"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.5"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Answer 2

您的方法很好，但是指定约束的方式有误。每个View只能设置一个start和一个end约束，所以需要去掉

app:layout_constraintEnd_toEndOf="parent"

从第一个 TextView 和

app:layout_constraintStart_toStartOf="parent"

从第二个开始，因为它们导致链无效。

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp">

    <TextView
        android:id="@+id/view_a"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_orange_dark"
        android:gravity="center"
        android:text="View A"
        app:layout_constraintEnd_toStartOf="@id/view_b"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/view_b"
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_red_light"
        android:gravity="center"
        android:text="View B"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@id/view_a"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

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