錯誤「產生的原因：拋出java.lang.ClassNotFoundException：」

Question

在安卓vogella教程就到SQLite的我也遇到惱人的問題與以下錯誤：

09-05 09:18:06.127: E/AndroidRuntime(981): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider" on path: DexPathList[[zip file "/data/app/com.example.de.vogella.android.todos-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.de.vogella.android.todos-1, /system/lib]] 

我跟着多次步步modyfying所有文件有R.類正確重新創建。關於這個錯誤的奇怪之處在於我不知道爲什麼在「com.example.de.vogella.android」中有關於「com.example」的任何內容。這是一種標準的生成名稱嗎？我的所有軟件包/名稱/路徑從未以「com.example」開頭（在此項目中）。我檢查了所有文件並找不到問題。從logcat的

更多輸出：

09-05 09:18:06.127: E/AndroidRuntime(981): FATAL EXCEPTION: main 
09-05 09:18:06.127: E/AndroidRuntime(981): java.lang.RuntimeException: Unable to get provider com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider: java.lang.ClassNotFoundException: Didn't find class "com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider" on path: DexPathList[[zip file "/data/app/com.example.de.vogella.android.todos-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.de.vogella.android.todos-1, /system/lib]] 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread.installProvider(ActivityThread.java:4882) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread.installContentProviders(ActivityThread.java:4485) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4425) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread.access$1300(ActivityThread.java:141) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.os.Handler.dispatchMessage(Handler.java:99) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.os.Looper.loop(Looper.java:137) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread.main(ActivityThread.java:5103) 
09-05 09:18:06.127: E/AndroidRuntime(981): at java.lang.reflect.Method.invokeNative(Native Method) 
09-05 09:18:06.127: E/AndroidRuntime(981): at java.lang.reflect.Method.invoke(Method.java:525) 
09-05 09:18:06.127: E/AndroidRuntime(981): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
09-05 09:18:06.127: E/AndroidRuntime(981): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
09-05 09:18:06.127: E/AndroidRuntime(981): at dalvik.system.NativeStart.main(Native Method) 
09-05 09:18:06.127: E/AndroidRuntime(981): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider" on path: DexPathList[[zip file "/data/app/com.example.de.vogella.android.todos-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.de.vogella.android.todos-1, /system/lib]] 
09-05 09:18:06.127: E/AndroidRuntime(981): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53) 
09-05 09:18:06.127: E/AndroidRuntime(981): at java.lang.ClassLoader.loadClass(ClassLoader.java:501) 
09-05 09:18:06.127: E/AndroidRuntime(981): at java.lang.ClassLoader.loadClass(ClassLoader.java:461) 
09-05 09:18:06.127: E/AndroidRuntime(981): at android.app.ActivityThread.installProvider(ActivityThread.java:4867) 
09-05 09:18:06.127: E/AndroidRuntime(981): ... 12 more 
09-05 09:18:06.156: E/ActivityThread(950): Failed to find provider info for de.vogella.android.todos.contentprovider 

在generall應用程序啓動，但是從一開始就得到崩潰與輸出：

Unfortunatelly, {AppName} has stopped. 

我的AndroidManifest.xml看起來像這樣

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="de.vogella.android.todos" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="13" 
     android:targetSdkVersion="18" /> 

    <application 
     android:allowBackup="true" 
     android:icon="@drawable/reminder" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <activity 
      android:name=".TodosOverviewActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity 
      android:name=".TodoDetailActivity" 
      android:windowSoftInputMode="stateVisible|adjustResize" 
      android:label="@string/title_activity_todo_detail" > 
     </activity> 

     <provider 
      android:name=".contentprovider.MyTodoContentProvider" 
      android:authorities="de.vogella.android.todos.contentproviderxxxxxxx" > 
     </provider> 
    </application> 

</manifest> 

我剛剛開始使用android，因此我缺少一些微不足道的東西。

非常感謝。

編輯 的<provider>發生變化：

<provider 
      android:name=".contentprovider.MyTodoContentProvider" 
      android:authorities="de.vogella.android.todos.contentprovider" > 
     </provider> 

結果：

Installation error: INSTALL_FAILED_CONFLICTING_PROVIDER 
Please check logcat output for more details. 
Launch canceled! 

與logcat的：

09-06 02:02:38.198: E/AndroidRuntime(864): FATAL EXCEPTION: main 
09-06 02:02:38.198: E/AndroidRuntime(864): java.lang.RuntimeException: Unable to get provider com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider: java.lang.ClassNotFoundException: Didn't find class "com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider" on path: DexPathList[[zip file "/data/app/com.example.de.vogella.android.todos-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.de.vogella.android.todos-1, /system/lib]] 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread.installProvider(ActivityThread.java:4882) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread.installContentProviders(ActivityThread.java:4485) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4425) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread.access$1300(ActivityThread.java:141) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.os.Handler.dispatchMessage(Handler.java:99) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.os.Looper.loop(Looper.java:137) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread.main(ActivityThread.java:5103) 
09-06 02:02:38.198: E/AndroidRuntime(864): at java.lang.reflect.Method.invokeNative(Native Method) 
09-06 02:02:38.198: E/AndroidRuntime(864): at java.lang.reflect.Method.invoke(Method.java:525) 
09-06 02:02:38.198: E/AndroidRuntime(864): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
09-06 02:02:38.198: E/AndroidRuntime(864): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
09-06 02:02:38.198: E/AndroidRuntime(864): at dalvik.system.NativeStart.main(Native Method) 
09-06 02:02:38.198: E/AndroidRuntime(864): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.de.vogella.android.todos.contentprovider.MyTodoContentProvider" on path: DexPathList[[zip file "/data/app/com.example.de.vogella.android.todos-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.de.vogella.android.todos-1, /system/lib]] 
09-06 02:02:38.198: E/AndroidRuntime(864): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53) 
09-06 02:02:38.198: E/AndroidRuntime(864): at java.lang.ClassLoader.loadClass(ClassLoader.java:501) 
09-06 02:02:38.198: E/AndroidRuntime(864): at java.lang.ClassLoader.loadClass(ClassLoader.java:461) 
09-06 02:02:38.198: E/AndroidRuntime(864): at android.app.ActivityThread.installProvider(ActivityThread.java:4867) 
09-06 02:02:38.198: E/AndroidRuntime(864): ... 12 more 
09-06 02:02:38.236: E/ActivityThread(834): Failed to find provider info for de.vogella.android.todos.contentprovider 

Answer 1

我曾經有過這個問題。代碼在以前工作並突然停止工作（在應用程序啓動時崩潰），當我同步並構建舊版代碼時。

修復只是關閉並重新啓動Eclipse並清理項目並清理所有依賴庫項目。然後它再次開始正常工作。

這是在Eclipse某種構建問題，刷新項目文件時。

更新：特別是，如果你不小心修改了「的.classpath」文件（恢復到舊版本）時，Eclipse/Android SDK中可以感到困惑，無法正常生成項目。當您重新啓動Eclipse並清理項目時，Eclipse將重新修改「.classpath」文件並正確構建。

Answer 2

更改這條線在你的代碼：

<provider 
     android:name="de.vogella.android.todos.contentprovider.MyTodoContentProvider" 
     android:authorities="de.vogella.android.todos.contentproviderxxxxxxx" > 
</provider> 

您的問題將得到解決。

Answer 3

不要忘記在你的Manifest中聲明內容提供者。

Answer 4

沒有com.example不是標準包名稱，它是根據位於項目根目錄下的AndroidManifest.xml文件生成的文件。

在清單文件中有一個稱爲包的屬性，它給應用程序一個唯一的名稱。

請檢查清單文件和我最好的猜測，修復包屬性作爲

<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="de.vogella.android.todos"