Android ClassNotFoundException主要活动

Question

I can't get my app to launch because it can't find my MainActivity, even though I have the proper .java file and I declared in my manifest, as you can see below:

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">
    <activity
        android:name="com.rakeshdas.smsblocker.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

EDIT The logcat is below and it says that it cannot find the class MainActivity :

 --------- beginning of crash
12-19 19:43:01.184      931-931/com.rakeshdas.smsblocker E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.rakeshdas.smsblocker, PID: 931
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.rakeshdas.smsblocker/com.rakeshdas.smsblocker.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.rakeshdas.smsblocker.MainActivity" on path: DexPathList[[zip file "/data/app/com.rakeshdas.smsblocker-2/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
        at android.app.ActivityThread.access$800(ActivityThread.java:144)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        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:898)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "com.rakeshdas.smsblocker.MainActivity" on path: DexPathList[[zip file "/data/app/com.rakeshdas.smsblocker-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 android.app.Instrumentation.newActivity(Instrumentation.java:1065)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2199)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
        at android.app.ActivityThread.access$800(ActivityThread.java:144)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        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:898)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
Suppressed: java.lang.NoClassDefFoundError: com.rakeshdas.smsblocker.MainActivity
        at dalvik.system.DexFile.defineClassNative(Native Method)
        at dalvik.system.DexFile.defineClass(DexFile.java:226)
        at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
        at dalvik.system.DexPathList.findClass(DexPathList.java:321)
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
        ... 14 more
Suppressed: java.lang.ClassNotFoundException: com.rakeshdas.smsblocker.MainActivity
        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

This could be worth a shot.

<manifest xmlns:android="http://schemas.andrwoid.com/apk/res/android"
    package="com.rakeshdas.smsblocker">
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            ...

Otherwise the cause of the issue could be somewhere else.

Answer 2

1) Close project

2) Restart eclipse

3) Open project

4) Clean project

that might help

Answer 3

请检查您的xml，下面写的行是否在顶部

<?xml version="1.0" encoding="utf-8"?>