约束在较新版本的 android studio 中无法正常工作

Question

I'm trying to center those 2 images in the center of the layout, without using any margins, just constraints. I've copied my instructor code, but in my version of android studio it's not working. Even if I download his activity-main.xml file, the bug is still there. You can see in the photos what I mean. This is my code / This is his

Answer 1

You need to chain both of your images horizontally and constraint one of them to the side of the screen, by doing that both of your images will be centered:

<?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">


<ImageView
    android:id="@+id/imageView3"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:src="@tools:sample/avatars[0]" />

<ImageView
    android:id="@+id/imageView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    app:layout_constraintBottom_toTopOf="@+id/button"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toEndOf="@+id/imageView5"
    app:layout_constraintTop_toBottomOf="@+id/imageView3"
    tools:src="@tools:sample/avatars[0]" />

<ImageView
    android:id="@+id/imageView5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:layout_constraintBottom_toBottomOf="@+id/imageView4"
    app:layout_constraintEnd_toStartOf="@+id/imageView4"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="@+id/imageView4"
    tools:src="@tools:sample/avatars[0]" />

<Button
    android:id="@+id/button"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    android:text="Button"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

After that your layout will look like this (when I cut the screenshot I did it a bit asymmetry but don't worry your layout will be good):