Android ConstraintLayout：将一个元素设置在另一个元素的中心

Question

我正在使用 ConstraintLayout 来创建 activity 视图

有一段代码：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="bottom"
    android:orientation="vertical"
    tools:context=".presentation.screens.registration.RegistrationActivity">

    <LinearLayout>...</LinearLayout>

    <Button
        android:id="@+id/login_next_btn"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:background="@drawable/button_green_disabled"
        android:layout_width="match_parent"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="24dp"
        android:text="@string/next"
        android:textColor="@color/font_white"
        android:textSize="16sp"
        android:layout_height="48dp"
        android:enabled="false"
        android:onClick="onNextClick"/>

    <ImageView
        android:id="@+id/loader_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="@+id/login_next_btn"
        android:src="@drawable/ic_loader"/>


</androidx.constraintlayout.widget.ConstraintLayout>

问题是：如何将ImageView(android:id="@+id/loader_image")设置在Button(@+id/login_next_btn)的中间？

Answer 1

试试这个：

<ImageView
        android:id="@+id/loader_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="@id/login_next_btn"
        app:layout_constraintRight_toRightOf="@id/login_next_btn"
        app:layout_constraintBottom_toBottomOf="@id/login_next_btn"
        app:layout_constraintTop_toTopOf="@id/login_next_btn"
        android:src="@drawable/ic_loader"/>

Answer 2

如果您必须将它设置在中心，只需更改图像的约束：

 app:layout_constraintBottom_toBottomOf="@id/login_next_btn"
 app:layout_constraintTop_toTopOf="@id/login_next_btn"
 app:layout_constraintStart_toStartOf="@id/login_next_btn"
 app:layout_constraintEnd_toEndOf="@id/login_next_btn"

Android ConstraintLayout：将一个元素设置在另一个元素的中心

Android ConstraintLayout: set one element in the center of another one

android

android-constraintlayout