android - 无法解析类 android.support.constraint.ConstraintLayout

Question

我得到这条红色的线

<android.support.constraint.ConstraintLayout 

和应用程序在打开时崩溃。
它工作正常，但现在出现错误:无法解析类 android.support.constraint.constraintlayout我还尝试将依赖项添加到模块 Gradle 文件中，并尝试通过 (add dependencies on androidx.constraints..,) 链接修复建议的修复程序，但仍然没有运气。我是新来的。请帮忙。
这是主要 Activity 的所有代码:

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/background"
    tools:context=".MainActivity">


    <Button
        android:id="@+id/act1Btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        android:text="Bill Calculation"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/askOptions"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        android:text="What you want to do?"
        android:textColor="#00BCD4"
        android:textSize="30sp"
        app:layout_constraintBottom_toTopOf="@+id/act1Btn"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn3"
        android:layout_width="130dp"
        android:layout_height="55dp"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        android:text="Tax Calc"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/act1Btn" />

    <Button
        android:id="@+id/btn4"
        android:layout_width="142dp"
        android:layout_height="46dp"
        android:text="Mobile Tax"
        app:layout_constraintBottom_toTopOf="@+id/btn3"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/act1Btn" />
</android.support.constraint.ConstraintLayout>

Answer 1

确保您拥有 maven.google.com build.gradle (Project: Name) 中声明的存储库文件:

repositories {
    google()
}

将库添加为 build.gradle (Module: app) 中的依赖项文件:

dependencies {
    implementation "androidx.constraintlayout:constraintlayout:2.1.0"
}

使用 ConstrainLayout写:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!--    Your Content Here    -->
    
</androidx.constraintlayout.widget.ConstraintLayout>