Question

我有一个项目正在进行中，一切都是正确的，因为我在android studio中使用一个Activity（登录活动）创建项目后来因为我想在项目上实现MVC，我在原始包com.otemainc.smartmenu中创建了另外三个包（app，activity和helper）然后我将LoginActivity.java文件移动到了活动包。然后将R类导入其中，将打包的声明行更改为正确的，但当我在手机上运行时，它会给我以下错误

    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

此错误是因为未找到您的活动类，因为您将其移动到另一个文件夹，您需要更改清单文件中的活动名称。你会看起来像这样

       <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>

这意味着正在原始根包中查找活动文件。您需要将名称变为activity.LoginActivity。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>

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