Java android studio没有类定义错误

我运行应用程序，突然发现这个错误。虽然所有文件都包含在我的项目中，但它仍然给我以下错误

错误日志：

E/AndroidRuntime: FATAL EXCEPTION: main
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime: java.lang.NoClassDefFoundError: com.TCYonline.android.TCY_K12.fragments.TutorialFragment
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at com.TCYonline.android.TCY_K12.adapters.TutorialPagerAdapter.<init>(TutorialPagerAdapter.java:52)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at com.TCYonline.android.TCY_K12.classes.TutorialActivity.onCreate(TutorialActivity.java:55)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.Activity.performCreate(Activity.java:5117)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1081)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2150)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.ActivityThread.access$600(ActivityThread.java:145)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1238)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:99)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:137)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5099)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:511)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:803)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:570)
11-13 10:08:34.270 8938-8938/com.TCYonline.android.TCY_K12 E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)
11-13 10:08:38.134 8938-8938/com.TCYonline.android.TCY_K12 I/Process: Sending signal. PID: 8938 SIG: 9

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将其添加到清单文件中的应用程序标记中，这将解决问题

android:name="android.support.multidex.MultiDexApplication"

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将其添加到清单文件中的应用程序标记中，这将解决问题

android:name="android.support.multidex.MultiDexApplication"

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确保在com.TCYonline.android.TCY_K12.fragments包中有TutorialFragment该文件在该项目中…确保在com.TCYonline.android.TCY_K12.fragments包中有TutorialFragment该文件在该项目中。。。