Android模型视图控制器实现给出了错误

Question

我有一个我正在从事的项目，从我在Android Studio中创建一个活动（登录活动）的项目之开始，一切都是正确的稍后，当我想在项目上实现MVC时，我在原始软件包com.otemainc.smartmenu中创建了另外三个软件包（应用，活动和助手），然后将loginactivity.java文件移至活动包中。然后将R类导入其中，将包装的声明行更改为正确的一行，但是当我使用手机时，它给了我以下错误

    12-16 13:07:27.352 4608-4608/com.otemainc.smartmenu E/AndroidRuntime: FATAL EXCEPTION: main                                                                      Process: com.otemainc.smartmenu, PID: 4608
   java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.otemainc.smartmenu/com.otemainc.smartmenu.LoginActivity}: java.lang.ClassNotFoundException: Didn't find class "com.otemainc.smartmenu.LoginActivity" on path: DexPathList[[zip file "/data/app/com.otemainc.smartmenu-1/base.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_dependencies_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_0_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_1_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_2_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_3_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_4_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_5_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_6_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_7_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_8_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2426)
   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2595)
    at android.app.ActivityThread.access$800(ActivityThread.java:178)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1470)
   at android.os.Handler.dispatchMessage(Handler.java:111)
   at android.os.Looper.loop(Looper.java:194)
   at android.app.ActivityThread.main(ActivityThread.java:5631)
   at java.lang.reflect.Method.invoke(Native Method)
   at java.lang.reflect.Method.invoke(Method.java:372)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)
  Caused by: java.lang.ClassNotFoundException: Didn't find class "com.otemainc.smartmenu.LoginActivity" on path: DexPathList[[zip file "/data/app/com.otemainc.smartmenu-1/base.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_dependencies_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_0_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_1_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_2_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_3_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_4_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_5_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_6_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_7_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_8_apk.apk", zip file "/data/app/com.otemainc.smartmenu-1/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at android.app.Instrumentation.newActivity(Instrumentation.java:1071)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2595) 
at android.app.ActivityThread.access$800(ActivityThread.java:178) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1470) 
at android.os.Handler.dispatchMessage(Handler.java:111) 
at android.os.Looper.loop(Looper.java:194) 
at android.app.ActivityThread.main(ActivityThread.java:5631) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754) 
Suppressed: java.lang.ClassNotFoundException: com.otemainc.smartmenu.LoginActivity
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
                            ... 13 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available

Answer 1

此错误是因为没有找到您的活动类，因为您将其移至另一个文件夹，因此您需要在清单文件中更改活动名称。您会指这个看起来像这样

       <activity
        android:name=".LoginActivity"
        android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

这意味着在原始根包中寻找活动文件。您需要将名称插入到活动中。该代码看起来像这样

       <activity
        android:name=".activity.LoginActivity"
        android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>