类强制转换异常在一个项目中而不是在另一个项目中。

Question

我一直在跟踪GCM教程，并且非常小心地在我的项目中正确地实现了相同的代码。但是当我运行这个项目时，我得到了ClassCast异常。我想我会错过一些东西，所以我从那篇文章中下载了源代码，并仔细地复制了我项目中的每一行，但我还是得到了同样的例外。请帮助解决错误。

12-10 23:41:25.812: E/AndroidRuntime(9549): FATAL EXCEPTION: main
12-10 23:41:25.812: E/AndroidRuntime(9549): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.exaple.oldgcm/com.exaple.oldgcm.MainActivity}: java.lang.ClassCastException: android.app.Application cannot be cast to com.exaple.oldgcm.Controller
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.ActivityThread.access$600(ActivityThread.java:128)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.os.Looper.loop(Looper.java:137)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.ActivityThread.main(ActivityThread.java:4517)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at java.lang.reflect.Method.invokeNative(Native Method)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at java.lang.reflect.Method.invoke(Method.java:511)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at dalvik.system.NativeStart.main(Native Method)
12-10 23:41:25.812: E/AndroidRuntime(9549): Caused by: java.lang.ClassCastException: android.app.Application cannot be cast to com.exaple.oldgcm.Controller
12-10 23:41:25.812: E/AndroidRuntime(9549):     at com.exaple.oldgcm.MainActivity.onCreate(MainActivity.java:33)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.Activity.performCreate(Activity.java:4470)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
12-10 23:41:25.812: E/AndroidRuntime(9549):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
12-10 23:41:25.812: E/AndroidRuntime(9549):     ... 11 more

Answer 1

我认为问题在于您没有在清单中设置应用程序名称。

请参阅此解决方案：

android.app.Application的android类异常