当我尝试在 Android Studio 中创建新 Activity 时 发生这些错误，在此错误之前我通常创建了一些 Activity (没有任何错误):
The following classes could not be found:
- android.support.constraint.ConstraintLayout ( Add constraint-layout library dependency to the project, Fix Build Path, Edit XML, Create Class)
- android.support.design.widget.CoordinatorLayout (Fix Build Path, Edit XML, Create Class)
- android.support.v7.widget.Toolbar (Fix Build Path, Edit XML, Create Class)
依赖库:
dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'androidx.appcompat:appcompat:1.0.2'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'com.android.support:support-v4:29.+'
implementation 'com.android.support:design:29.+'
implementation 'com.android.support:appcompat-v7:29.+'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test:runner:1.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
implementation 'com.google.android.material:material:1.0.0'
implementation 'com.squareup.retrofit2:retrofit:2.0.2'
implementation 'com.squareup.retrofit2:converter-gson:2.0.2'
implementation 'com.squareup.picasso:picasso:2.5.2'
implementation 'de.hdodenhof:circleimageview:3.0.0'
implementation 'com.mikhaellopez:circularimageview:3.2.0'
implementation 'com.google.android.gms:play-services-base:11.0.1'
implementation 'com.google.android.gms:play-services-basement:11.0.1'
implementation 'com.google.android.gms:play-services-safetynet:11.0.1'
implementation 'com.google.android.gms:play-services-tasks:11.0.1'
}
最佳答案
您混淆了 AndroidX 依赖项与 AppCompat。要么从 Refactor -> Migrate to AndroidX 迁移到 AndroidX，要么使用 AppCompat。
正如在您的代码中一样，您已使用约束布局的两个依赖项。解决您的问题的最简单的解决方案是删除该行
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
关于java - 如何修复Android Studio中的 "Missing classes"错误？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57511034/