android - 添加库项目后找不到类异常

Question

我已经创建了一个库项目作为 .jar 文件并尝试在另一个项目中使用它。但是我在使用它时遇到 Class not found 异常。我在我的 list 文件中添加了库中的所有 Activity 及其所有权限。但仍然遇到同样的错误。

这是我的 list 文件

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="@string/google_maps_key" />
    <activity android:name=".Activities.MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name="in.moovo.moovobroker.Activity.Mainactivity"/>
</application>

我的错误堆栈跟踪在这里:

java.lang.NoClassDefFoundError: Failed resolution of: Lin/moovo/moovobroker/R$layout;
at in.moovo.moovobroker.Activity.Mainactivity.onCreate(Mainactivity.java:85)
at android.app.Activity.performCreate(Activity.java:6072)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2315)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2424)
at android.app.ActivityThread.access$900(ActivityThread.java:155)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:139)
at android.app.ActivityThread.main(ActivityThread.java:5298)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:950)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:745)
Caused by: java.lang.ClassNotFoundException: Didn't find class "in.moovo.moovobroker.R$layout" on path: DexPathList[[zip file "/data/app/in.moovo.moovobrokerappmapview-2/base.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 in.moovo.moovobroker.Activity.Mainactivity.onCreate(Mainactivity.java:85) 
at android.app.Activity.performCreate(Activity.java:6072) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2315) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2424) 
at android.app.ActivityThread.access$900(ActivityThread.java:155) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:139) 
at android.app.ActivityThread.main(ActivityThread.java:5298) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:950) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:745) 
Suppressed: java.lang.ClassNotFoundException: in.moovo.moovobroker.R$layout
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)
... 15 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available

Answer 1

此错误不适用于 Activity。这是用于 in/moovo/moovobroker/R$layout 的，您将其用于 in.moovo.moovobroker.Activity.Mainactivity。

您使用的方式不正确。当您决定使用 jar 文件时，jar 中的类不应依赖任何外部资源。

正确的方法是使用aar 文件。阅读如何 Create aar file in Android Studio