Java 错误“无法实例化活动…在路径：DexPathList上找不到类”

当我尝试在Eclipse上构建应用程序时，出现以下错误：

05-20 15:04:51.202: E/AndroidRuntime(1543): FATAL EXCEPTION: main
05-20 15:04:51.202: E/AndroidRuntime(1543): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.devyanlab.testapp/com.devyanlab.testapp.activities.IntroActivity}: java.lang.ClassNotFoundException: Didn't find class "com.devyanlab.testapp.activities.IntroActivity" on path: DexPathList[[zip file "/data/app/com.devyanlab.testapp-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.devyanlab.testapp-1, /system/lib]]
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.os.Looper.loop(Looper.java:137)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.ActivityThread.main(ActivityThread.java:5103)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at java.lang.reflect.Method.invokeNative(Native Method)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at java.lang.reflect.Method.invoke(Method.java:525)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at dalvik.system.NativeStart.main(Native Method)
05-20 15:04:51.202: E/AndroidRuntime(1543): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.devyanlab.testapp.activities.IntroActivity" on path: DexPathList[[zip file "/data/app/com.devyanlab.testapp-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.devyanlab.testapp-1, /system/lib]]
05-20 15:04:51.202: E/AndroidRuntime(1543):     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
05-20 15:04:51.202: E/AndroidRuntime(1543):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
05-20 15:04:51.202: E/AndroidRuntime(1543):     ... 11 more

应用程序中没有错误。我试过其他方法：

清理应用程序 在首选项>Java构建路径上检查Android私有库 检查AndroidManifest.xml上的活动路径 多次重新启动Eclipse 重新启动emulator Genymotion

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有什么想法吗？

右键单击项目并选择属性。“属性”面板将打开。从左边的菜单进入Java构建路径->订单和导出。从下面的列表中，检查添加到项目中的库或外部jar。最后清理项目并运行