请这将是不重复的问题。

Please this will be not DUPLICATE question

不知道，但我已经把的.jar的libs文件夹中，也做了以下处理

Don't know but I have already put .jar in libs folder and also done following process

和也

我已检查过本I'm获得了java.lang.ClassNotFoundException：com.mysql.jdbc.Driver

我做了几个项目，但在我第一次得到这个保管箱示例项目

I have done several projects but in first time I am getting with this dropbox sample Project

Lotcat是

10-14 13:01:00.580: W/dalvikvm(2902): threadid=1: thread exiting with uncaught exception (group=0x430d5140)
10-14 13:01:00.580: E/AndroidRuntime(2902): FATAL EXCEPTION: main
10-14 13:01:00.580: E/AndroidRuntime(2902): Process: com.dropbox.sample.hellodropbox, PID: 2902
10-14 13:01:00.580: E/AndroidRuntime(2902): java.lang.NoClassDefFoundError: com.dropbox.sync.android.DbxAccountManager
10-14 13:01:00.580: E/AndroidRuntime(2902):     at com.dropbox.sample.hellodropbox.HelloDropboxActivity.onCreate(HelloDropboxActivity.java:44)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.Activity.performCreate(Activity.java:5403)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.ActivityThread.access$800(ActivityThread.java:139)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.os.Handler.dispatchMessage(Handler.java:102)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.os.Looper.loop(Looper.java:149)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at android.app.ActivityThread.main(ActivityThread.java:5257)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at java.lang.reflect.Method.invokeNative(Native Method)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at java.lang.reflect.Method.invoke(Method.java:515)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:817)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:633)
10-14 13:01:00.580: E/AndroidRuntime(2902):     at dalvik.system.NativeStart.main(Native Method)

即使有一类Refrenced库

Even there is a class in Refrenced Libraries

请只是尝试用这种

https://www.dropbox.com/developers/downloads/sdks/datastore/android/dropbox-android-sync-sdk-3.1.1.zip SDK如果您也越来越此类错误或不 ？

https://www.dropbox.com/developers/downloads/sdks/datastore/android/dropbox-android-sync-sdk-3.1.1.zip SDK if you are also getting this kind of error or not ?

推荐答案

我有同样的问题。 Dropbox的同步-SDK-的android.jar是存在的类路径上，但这些类不包括以在构建过程中产生的apk。 后来我注意到，在Android编译控制台多个错误：

I had the same problem. The dropbox-sync-sdk-android.jar was existed on the class-path, but the classes were not included to resulting apk during build process. Later I noticed multiple errors in Android build console:

 [dx] bad class file magic (cafebabe) or version (0033.0000)

看起来像Dropbox的API是编译的JDK 1.7，并尝试使用JDK 1.6这个jar构建APK的时候，你会有麻烦

Looks like Dropbox API is compiled against JDK 1.7 and you will have troubles when trying to build APK with this jar using JDK 1.6

我通过更新编译器遵从性级别修复了这个问题：

I fixed this issue by updating Compiler compliance level:

Project->Properties->Java Compiler->Compiler compliance level->1.7

另外，还要确保你的Andr​​oid SDK内置工具是V19或更高版本：

Also make sure that your Android SDK Build-tools are v19 or later:

Android SDK Manager->Android SDK Build-tools->check v21.0.2->uncheck v17(my case)