无法找到明确的活动类，无法实例化活动

Question

即时通讯想知道为什么我得到上述错误，当我试图修复我的清单。我宣布我的活动我的表现是这样的：

<activity 
     android:name="com.joyce.cit.DummyActivity" 
     android:label="@string/title_activity_dummy" > 
     <intent-filter> 
      <action android:name="android.intent.action.DUMMYACTIVITY" /> 

      <category android:name="android.intent.category.DEFAULT" /> 
     </intent-filter> 
    </activity> 

，并得到了我的logcat此错误：

07-19 10:08:52.290: E/AndroidRuntime(8852): FATAL EXCEPTION: main 
07-19 10:08:52.290: E/AndroidRuntime(8852): 
android.content.ActivityNotFoundException:  
Unable to find explicit activity class 
{com.joyce.cit.pdfview/com.joyce.cit.pdfview.DummyActivity}; have you declared this 
activity in your AndroidManifest.xml? 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1508) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.app.Instrumentation.execStartActivity(Instrumentation.java:1384) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.app.Activity.startActivityForResult(Activity.java:3190) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.app.Activity.startActivity(Activity.java:3297) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
com.joyce.cit.pdfview.SplashActivity$1.onClick(SplashActivity.java:30) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.view.View.performClick(View.java:3511) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.view.View$PerformClick.run(View.java:14110) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.os.Handler.handleCallback(Handler.java:605) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.os.Handler.dispatchMessage(Handler.java:92) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.os.Looper.loop(Looper.java:137) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
android.app.ActivityThread.main(ActivityThread.java:4424) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
java.lang.reflect.Method.invokeNative(Native Method) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at  
java.lang.reflect.Method.invoke(Method.java:511) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
07-19 10:08:52.290: E/AndroidRuntime(8852):  at 
dalvik.system.NativeStart.main(Native Method) 

，改变我的活动我的表现是这样的：

<activity 
     android:name=".DummyActivity" 
     android:label="@string/title_activity_dummy" > 
     <intent-filter> 
      <action android:name="android.intent.action.DUMMYACTIVITY" /> 

      <category android:name="android.intent.category.DEFAULT" /> 
     </intent-filter> 
    </activity> 

和在我的logcat中得到这个错误：

07-19 10:15:31.930: E/AndroidRuntime(9038): FATAL EXCEPTION: main 
07-19 10:15:31.930: E/AndroidRuntime(9038): java.lang.RuntimeException: Unable to 
instantiate activity 
ComponentInfo{com.joyce.cit.pdfview/com.joyce.cit.pdfview.DummyActivity}: 
java.lang.InstantiationException: can't instantiate class 
com.joyce.cit.pdfview.DummyActivity 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.ActivityThread.access$600(ActivityThread.java:123) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.os.Handler.dispatchMessage(Handler.java:99) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.os.Looper.loop(Looper.java:137) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.ActivityThread.main(ActivityThread.java:4424) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
java.lang.reflect.Method.invokeNative(Native Method) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
java.lang.reflect.Method.invoke(Method.java:511) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
dalvik.system.NativeStart.main(Native Method) 
07-19 10:15:31.930: E/AndroidRuntime(9038): Caused by: 
java.lang.InstantiationException: can't instantiate class 
com.joyce.cit.pdfview.DummyActivity 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
java.lang.Class.newInstanceImpl(Native Method) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
java.lang.Class.newInstance(Class.java:1319) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.Instrumentation.newActivity(Instrumentation.java:1023) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871) 
07-19 10:15:31.930: E/AndroidRuntime(9038):  ... 11 more 

对不起，我是Android新手。我只能理解这一点。请有人解释这一点。非常感谢你。

Answer 1

您声明了com.joyce.cit.DummyActivity，logcat表示您正在尝试启动com.joyce.cit.pdfview.DummyActivity。