错误类型3错误:活动类{}不存在

我有一个IntelliJ Android项目，我成功地导入到Android Studio 0.4.0。如果我不改变manifest中的任何东西，它就能很好地工作。然而，当我想要改变启动器活动并运行时，它会失败，并出现以下错误:

Launching application: com.trackingeng/LandingActivity.
DEVICE SHELL COMMAND: am start -D -n "com.trackingeng/LandingActivity"  
    -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Starting: Intent { act=android.intent.action.MAIN  
    cat=[android.intent.category.LAUNCHER] cmp=com.trackingeng/LandingActivity }
Error type 3
Error: Activity class {com.trackingeng/LandingActivity} does not exist.

当我点击同步项目与Gradle文件，它输出:

Project Sync
The project 'TrackingEng' is not a Gradle-based project

运行设置:

当前回答

删除虚拟设备并重新下载(在Android Studio 3.1.3上测试，2019年1月)。

2019-02-01 02:26:19

其他回答

Had the same error, with a much newer version of Android Studio (version 4.1) . A fresh install of Android Studio + a fresh "basic Activity" template would run into error type 3 for hours. I am on win 10 - my problem was how to kill the gradle cache. A good answer above showed a screen snapshot from gradle, but i didn't find it in Android Studio 4.1. Also the env vars for gradle had not been set , and the commandline for gradle didn't work. So .. here is how it worked finally. I went to C:\Users\myusername\ .gradle. This has subdir "caches". I deleted everything inside. Worked ! I did close Android Studio before, restarted and then it worked nicely. Ah forgot one thing- i run the device emulator (defauöt device), i.e. no physical device yet.

2020-10-14 15:58:57

只是做一个干净的构建对我来说很有用。

要进行干净的构建，请执行以下操作: