Barrier doesn't set to referenceIds in constraint layout?

问题

hey last few days I am exploring about the constraint layout.the concept of barrier I can understand but when i implement I can't get the correct output.

I want to set the barrier in the right direction to reference Id's. But barrier doesn't work.it should set for the views which are nameLabel and passionLabel. please help me. thank you in advance. This is the current output

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:id="@+id/activity_main_barriers"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="8dp"
        android:fontFamily="@font/roboto_bold"
        android:text="@string/barriers"
        android:textColor="@color/black"
        android:textSize="25sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/header"
        android:layout_width="0dp"
        android:layout_height="149dp"
        android:layout_marginTop="8dp"
        android:scaleType="centerCrop"
        android:src="@drawable/arun"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:fontFamily="@font/roboto_bold"
        android:text="Arun Pandian"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.032"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/header" />
    <!--@string/hobbies-->
    <TextView
        android:id="@+id/passionLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:labelFor="@+id/etPassion"
        android:text="@string/passion"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="15sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/etPassion"
        app:layout_constraintStart_toStartOf="@+id/nameLabel" />
    <TextView
        android:id="@+id/nameLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:fontFamily="@font/roboto_italic"
        android:labelFor="@+id/cameraType"
        android:text="@string/name"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="15sp"
        app:layout_constraintBaseline_creator="1"
        app:layout_constraintBaseline_toBaselineOf="@+id/etName"
        app:layout_constraintLeft_creator="1"
        app:layout_constraintStart_toStartOf="@+id/title"
        app:layout_editor_absoluteX="16dp"
        app:layout_editor_absoluteY="189dp"
        tools:layout_constraintBaseline_creator="0"
        tools:layout_constraintLeft_creator="0" />
    <EditText
        android:id="@+id/etPassion"
        android:layout_width="217dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:text="Developing softwares"
        app:layout_constraintEnd_toEndOf="@+id/etName"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="@+id/etName"
        app:layout_constraintTop_toBottomOf="@+id/etName"
        app:layout_editor_absoluteX="73dp"
        app:layout_editor_absoluteY="225dp"
        tools:layout_constraintLeft_creator="1"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintTop_creator="0" />
    <EditText
        android:id="@+id/etName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="148dp"
        android:inputType="textPersonName"
        android:text="Arun Pandian"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/tvName"
        app:layout_constraintTop_toBottomOf="@+id/title"
        tools:layout_constraintLeft_creator="1"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintTop_creator="0" />
    <android.support.constraint.Barrier
        android:id="@+id/barrier"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="end"
        app:constraint_referenced_ids="nameLabel,passionLabel"
        tools:layout_editor_absoluteX="411dp" />
</android.support.constraint.ConstraintLayout>

回答1:

Try this: you have to give both edittext start constraint to barrier.

Also when I see in My android studio xml my output is same as you post in your question image. check http://prntscr.com/mkdtgb

But when I see in device it's working

 <android.support.constraint.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:id="@+id/activity_main_barriers"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="8dp"
        android:text="barriers"
        android:textColor="@android:color/black"
        android:textSize="25sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/header"
        android:layout_width="0dp"
        android:layout_height="149dp"
        android:layout_marginTop="8dp"
        android:scaleType="centerCrop"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <TextView
        android:id="@+id/title"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="15dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:text="Arun Pandian"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/header" />
    <!--@string/hobbies-->
    <TextView
        android:id="@+id/passionLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:labelFor="@+id/etPassion"
        android:text="passios"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="15sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/etPassion"
        app:layout_constraintStart_toStartOf="@+id/nameLabel" />

    <EditText
        android:id="@+id/etPassion"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:layout_marginStart="16dp"
        android:text="Developing softwares"
        app:layout_constraintEnd_toEndOf="@+id/etName"
        app:layout_constraintStart_toEndOf="@+id/barrier2"
        app:layout_constraintTop_toBottomOf="@+id/etName" />

    <TextView
        android:id="@+id/nameLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:labelFor="@+id/cameraType"
        android:text="namegfhfgdfgdfgdfgdfgdfgdf"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="15sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/etName"
        app:layout_constraintStart_toStartOf="parent" />

    <EditText
        android:id="@+id/etName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:inputType="textPersonName"
        android:text="Arun Pandian"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/barrier2"
        app:layout_constraintTop_toBottomOf="@+id/title" />


    <android.support.constraint.Barrier
        android:id="@+id/barrier2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="end"
        app:constraint_referenced_ids="nameLabel,passionLabel" />

</android.support.constraint.ConstraintLayout>

回答2:

I resolved this issue by updating the ConstraintLayout library

From

implementation 'com.android.support.constraint:constraint-layout:2.0.0-alpha2'

To this

implementation 'com.android.support.constraint:constraint-layout:2.0.0-alpha3'

回答3:

I had a similar issue when using

implementation 'com.android.support.constraint:constraint-layout:1.1.3'

The same code was working in one project but not in another, both using the same version of the constraint-layout

If it works on device and but not in the layout editor, then try to force refresh the layout in the editor

回答4:

This seems to be a rendering bug in the Preview in Android Studio 3.3. The barrier will works at runtime on the emulator.

来源：https://stackoverflow.com/questions/54650506/barrier-doesnt-set-to-referenceids-in-constraint-layout