Android ClassNotFoundException：未在路径上找到类
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Android ClassNotFoundException: Didn't find class on path
提问by user3129072
I can't find the solution of this error.Can you please give the permanent solution.i have no idea how to solve it can u help me .Thanks
我找不到此错误的解决方案。请您提供永久解决方案。我不知道如何解决，您能帮我吗？谢谢
01-04 11:06:42.302: E/AndroidRuntime(1906): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{e.gochat/e.gochat.gochat.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "e.gochat.gochat.MainActivity" on path: DexPathList[[zip file "/data/app/e.gochat-1.apk"],nativeLibraryDirectories=[/data/app-lib/e.gochat-1, /vendor/lib, /system/lib]]
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2102)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.ActivityThread.access0(ActivityThread.java:135)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.os.Handler.dispatchMessage(Handler.java:102)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.os.Looper.loop(Looper.java:137)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.ActivityThread.main(ActivityThread.java:4998)
01-04 11:06:42.302: E/AndroidRuntime(1906): at java.lang.reflect.Method.invokeNative(Native Method)
01-04 11:06:42.302: E/AndroidRuntime(1906): at java.lang.reflect.Method.invoke(Method.java:515)
01-04 11:06:42.302: E/AndroidRuntime(1906): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
01-04 11:06:42.302: E/AndroidRuntime(1906): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
01-04 11:06:42.302: E/AndroidRuntime(1906): at dalvik.system.NativeStart.main(Native Method)
01-04 11:06:42.302: E/AndroidRuntime(1906): Caused by: java.lang.ClassNotFoundException: Didn't find class "e.gochat.gochat.MainActivity" on path: DexPathList[[zip file "/data/app/e.gochat-1.apk"],nativeLibraryDirectories=[/data/app-lib/e.gochat-1, /vendor/lib, /system/lib]]
01-04 11:06:42.302: E/AndroidRuntime(1906): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
01-04 11:06:42.302: E/AndroidRuntime(1906): at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
01-04 11:06:42.302: E/AndroidRuntime(1906): at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
01-04 11:06:42.302: E/AndroidRuntime(1906): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2093)
01-04 11:06:42.302: E/AndroidRuntime(1906): ... 11 more
01-04 11:07:06.772: I/Process(1906): Sending signal. PID: 1906 SIG: 9
This is my app Manifest XML
这是我的应用程序清单 XML
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="e.gochat"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="9"
android:targetSdkVersion="18" />
<permission
android:name="e.gochat.permission.C2D_MESSAGE"
android:protectionLevel="signature" />
<uses-permission android:name="e.gochat.permission.C2D_MESSAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<application
android:name="e.gochat.Common"
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="e.gochat.MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="e.gochat.ChatActivity"
/>
<activity
android:name="e.gochat.SettingsActivity"
android:label="@string/title_activity_settings" />
<receiver
android:name="e.gochat.client.GcmBroadcastReceiver"
android:permission="com.google.android.c2dm.permission.SEND" >
<intent-filter>
<action android:name="com.google.android.c2dm.intent.RECEIVE" />
<category android:name="e.gochat" />
</intent-filter>
</receiver>
<provider
android:name="e.gochat.DataProvider"
android:authorities="e.gochat.provider"
android:exported="false">
</provider>
</application>
I'm not sure what's wrong here. I've added the .jar file in the java build path. And yet I'm getting this classnotfound exception. The app loads when I import the android.app.Application
我不确定这里出了什么问题。我在 java 构建路径中添加了 .jar 文件。然而，我收到了这个 classnotfound 异常。当我导入 android.app.Application 时应用程序加载
采纳答案by ramaral
I don't know for sure what is your package name, but if it is e.gochatdo this.
我不确定你的包名是e.gochat什么，但如果是这样。
Add package="e.gochat"to manifest.xml
添加package="e.gochat"到 manifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="e.gochat"
.....
.....
>
On each activity declaration for android:nameput a dot before activity name:
在每个活动声明上，android:name在活动名称前放一个点：
<activity
android:name=".MainActivity">
............
</activity>
<activity
android:name=".ChatActivity">
EDIT
编辑
After your edited I can see e.gochatis your package name.
Now you only need to remove e.gochatfrom each activity/provider/receiver name as I said in second part of my answer.
Android will add that for you.
在您编辑后，我可以看到e.gochat您的包名称。
现在，您只需e.gochat要从每个活动/提供者/接收者的名称中删除，就像我在回答的第二部分中所说的那样。
Android 会为您添加。
回答by Kishor N R
I have solved this problem by disabling the instant run option of android studio. To disable Instant Run Goto File -> Settings -> Build,Execution, Deployment -> Instant Run -> Uncheck the checkbox for instant run
我通过禁用 android studio 的即时运行选项解决了这个问题。禁用即时运行转到文件 -> 设置 -> 构建、执行、部署 -> 即时运行 -> 取消选中即时运行的复选框
回答by styler1972
Using Android Studio
使用 Android Studio
After upgrading to Android Stuido 0.8.2, I had this problem. I tried a lot of things, including
升级到Android Stuido 0.8.2 后，我遇到了这个问题。我尝试了很多东西，包括
- Clean project
- Clean project (gradle clean)
- Invalidate Caches and Restart
- De-qualify the Activity Name in AndroidManifest.xml (.MyActivity)
- 清洁工程
- 清洁项目（gradle clean）
- 使缓存无效并重新启动
- 取消限定 AndroidManifest.xml (.MyActivity) 中的活动名称
Nothing worked until I re-imported the entire project.
在我重新导入整个项目之前没有任何效果。
File -> Close Project -> Import Project... -> Choose the same project -> OK
File -> Close Project -> Import Project... -> Choose the same project -> OK
This fixed it for me
这为我修好了
回答by live-love
Uninstalling the app in the device and running the project again fixed it for me.
卸载设备中的应用程序并再次运行该项目为我修复了它。
回答by Tom Redman
For me, this was occurring on devices running < Android 5.0 because I didn't have multidex support enabled(this is, over 65k total methods incl. libs). Multidex is automatic and native on Android 5.0+ (specifically, devices using ART).
对我来说，这发生在运行 < Android 5.0 的设备上，因为我没有启用 multidex 支持（这是，包括库在内的总共超过 65k 的方法）。Multidex 在 Android 5.0+（特别是使用ART 的设备）上是自动和原生的。
回答by Himadri Pant
The reason why this was affecting me was due to an incorrect path name in a layout file
这影响我的原因是布局文件中的路径名不正确
<android.support.v4.app.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.app.view.ViewPager>
The correct absolute path of ViewPager is
ViewPager的正确绝对路径是
android.support.v4.view.ViewPager
After correcting the path it worked. I did not have to prefix the activity name with a '.'.
更正路径后，它起作用了。我不必在活动名称前加上“.”。
回答by Kushal
The problem was solved by removing MultiDexSupport from build.gradlefile :
通过从build.gradle文件中删除 MultiDexSupport 解决了这个问题：
defaultConfig {
multiDexEnabled true // This line was causing above problem
}
Removing the MultiDexSupport solved the problem
删除 MultiDexSupport 解决了问题
回答by Amit
This issue has multiple answers based on the different scenario. I was getting the same error when using a library(.aar) in my Android Studio project.
这个问题根据不同的场景有多个答案。在我的 Android Studio 项目中使用库 (.aar) 时，我遇到了同样的错误。
The root cause in my case was that I missed to add a third party lib dependency in app's build.gradle file which was being used by the .aar file.
在我的案例中，根本原因是我错过了在应用程序的 build.gradle 文件中添加第三方库依赖项，该文件正被 .aar 文件使用。
e.g:- The library(.aar) was using 'com.squareup.okhttp3:okhttp:3.4.1'. So I had to add
例如：- 库（.aar）使用的是“com.squareup.okhttp3:okhttp:3.4.1”。所以我不得不补充
compile 'com.squareup.okhttp3:okhttp:3.4.1'
编译'com.squareup.okhttp3:okhttp:3.4.1'
in the app's build.gradle. Hope it helps someone.
在应用程序的 build.gradle 中。希望它可以帮助某人。
回答by Zuop
ANDROID STUDIOIn addittion to Kishor's answer:
ANDROID STUDIO除了 Kishor 的回答：
The error occured on my small project when I enabled multiDexEnabled = truein the gradle defaultconfig.
Using the generated .apk file crashes on start of the app with the known error message.
当我multiDexEnabled = true在 gradle defaultconfig 中启用时，我的小项目发生了错误。使用生成的 .apk 文件在应用程序启动时崩溃并显示已知错误消息。
For me it was solved when I built the .apk file via gradle (right side of android studio) -> "yourapp" -> Tasks- > install -> installDebug
对我来说，当我通过 gradle（android studio 的右侧）->“yourapp”-> 任务-> 安装-> installDebug 构建 .apk 文件时它就解决了
Hope this helps someone with this strange error
希望这可以帮助遇到这个奇怪错误的人
回答by prom85
I implemented a listener that was not available in the android version I was running yet and this led to the same error.
我实现了一个在我运行的 android 版本中不可用的侦听器，这导致了同样的错误。
Example MainActivity:
示例主活动：
// RecyclerView.OnScrollChangeListener is only available on API >= 23
public class MainActivity implements RecyclerView.OnScrollChangeListener
{
}
Running this activity on a device with API < 23 will result in this error as well...
在 API < 23 的设备上运行此活动也会导致此错误...
