ClassNotFoundException：没有找到类

Question

我对 Gradle 文件进行了一些更改，当我尝试运行该应用程序时出现此错误：java.lang.ClassNotFoundException：没有找到类“androidx.support.constraint.ConstraintLayout”

----------XML------------

<?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:configChanges = "orientation|keyboardHidden"

    tools:context=".MainActivity">

    <ImageView

        android:id="@+id/imageView"

        android:layout_width="607dp"

        android:layout_height="313dp"

        android:layout_marginStart="8dp"

        android:layout_marginTop="8dp"

        android:layout_marginEnd="8dp"

        android:layout_marginBottom="8dp"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toTopOf="parent"

        app:srcCompat="@mipmap/ic_launcher" />

</android.support.constraint.ConstraintLayout>

----------摇篮应用--------

apply plugin: 'com.android.application'

android {

    compileSdkVersion 28

    defaultConfig {

        applicationId "com.example.eladk.flagged"

        minSdkVersion 27

        targetSdkVersion 28

        versionCode 1

        versionName "1.0"

        testInstrumentationRunner 

    "android.support.test.runner.AndroidJUnitRunner"

        }

        buildTypes {

            release {

                minifyEnabled false

                proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'

            }

        }

    }

Answer 1

您应该将您的项目迁移到 AndroidX，例如ConstraintLayout&nbsp;implementation&nbsp;"androidx.constraintlayout:constraintlayout:$constraintLayout_version"