Android 二进制XML文件行#12:膨胀类片段时出错

我有一个奇怪的错误。我在做一个实现谷歌地图v2的项目。一切正常，直到有一天我在日食中出错。不知何故，我不能清理这个项目。因此，我删除了该项目，并从svn中签出agin。在那之后，我试着清洁它，它工作了。当我想运行该项目时，我遇到以下错误：

08-05 00:45:21.636: E/AndroidRuntime(16997): FATAL EXCEPTION: main
08-05 00:45:21.636: E/AndroidRuntime(16997): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.travelbook/com.example.travelbook.MainActivity}: android.view.InflateException: Binary XML file line #12: Error inflating class fragment
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2077)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2104)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.ActivityThread.access$600(ActivityThread.java:134)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1247)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.os.Looper.loop(Looper.java:137)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.ActivityThread.main(ActivityThread.java:4624)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at java.lang.reflect.Method.invokeNative(Native Method)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at java.lang.reflect.Method.invoke(Method.java:511)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at  com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at dalvik.system.NativeStart.main(Native Method)
08-05 00:45:21.636: E/AndroidRuntime(16997): Caused by: android.view.InflateException: Binary XML file line #12: Error inflating class fragment
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:699)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:741)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.view.LayoutInflater.inflate(LayoutInflater.java:491)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:252)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Activity.setContentView(Activity.java:1837)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at com.example.travelbook.MainActivity.onCreate(MainActivity.java:63)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Activity.performCreate(Activity.java:4479)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1050)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2041)
08-05 00:45:21.636: E/AndroidRuntime(16997):    ... 11 more
08-05 00:45:21.636: E/AndroidRuntime(16997): Caused by: android.app.Fragment$InstantiationException: Unable to instantiate fragment com.google.android.gms.maps.MapFragment: make sure class name exists, is public, and has an empty constructor that is public
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Fragment.instantiate(Fragment.java:581)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Fragment.instantiate(Fragment.java:549)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Activity.onCreateView(Activity.java:4249)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:675)
08-05 00:45:21.636: E/AndroidRuntime(16997):    ... 21 more
08-05 00:45:21.636: E/AndroidRuntime(16997): Caused by: java.lang.ClassNotFoundException: com.google.android.gms.maps.MapFragment
08-05 00:45:21.636: E/AndroidRuntime(16997):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
08-05 00:45:21.636: E/AndroidRuntime(16997):    at android.app.Fragment.instantiate(Fragment.java:571)
08-05 00:45:21.636: E/AndroidRuntime(16997):    ... 24 more

这对我来说没有意义，因为我没有对我的代码做任何更改，正如我所说的，项目正在运行。有人知道为什么会这样吗？如何解决呢？我正在使用EclipseJuno

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谢谢

确保构建路径的“订购和导出”部分设置正确：非常感谢。是的，现在可以用了