com.myapp E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.myapp,PID: 29605
    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.myapp/com.myapp.Login}: java.lang.ClassNotFoundException: Didn't find class "com.myapp.Login" on path: DexPathList[[zip file "/data/app/com.myapp-1/base.apk"],nativeLibraryDirectories=[/vendor/lib,/system/lib]]
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3023)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3294)
    at android.app.ActivityThread.access$1000(ActivityThread.java:210)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1704)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:6938)
    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:1404)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
    Caused by: java.lang.ClassNotFoundException: Didn't find class "com.myapp.Login" on path: DexPathList[[zip file "/data/app/com.myapp-1/base.apk"],/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:1094)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3013)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3294)
    at android.app.ActivityThread.access$1000(ActivityThread.java:210)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1704)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:6938)
    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:1404)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
    Suppressed: java.lang.ClassNotFoundException: com.myapp.Login
    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

这是我的gradle.build

apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'
android {
    compileSdkVersion 'Google Inc.:Google APIs:23'
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "com.myapp"
        minSdkVersion 14
        targetSdkVersion 22
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'),'proguard-rules.txt'
        }
    }
}

dependencies {
//    compile files('libs/smack-core-4.0.7.jar')
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.google.android.gms:play-services:7.8.0'
    compile 'com.google.maps.android:android-maps-utils:0.4+'
}

到目前为止我已经尝试过
1)清理和重建项目
2)删除构建文件夹并重建项目/重启Android Studio
3)切换到金丝雀频道以及开发频道和更新
4)在“设置”中选中并取消选中离线模式
显然这是一个错误,但有解决方案吗？如何撤消最近的更新？任何帮助深表感谢.