title: signed apk crashing when downloaded from playstore
body: <p>I made a simple app with a webview and published it to the playstore - everything worked fine. Recently i updated the ip of the webview, changed the version code, generated a signed apk and re-uploaded to playstore. However, when i downloaded it to test, it crashes. </p>
  
  <pre><code>    08-21 03:48:34.916 926-4059/? I/ActivityManager: START u0 
      {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] 
      flg=0x10000000 pkg=com.rayzor536.appointments 
      cmp=com.rayzor536.appointments/.MainActivity} from uid 10039
      08-21 03:48:34.995 926-4061/? I/ActivityManager: Start proc 703 
      4:com.rayzor536.appointments/u0a137 for activity 
      com.rayzor536.appointments/.MainActivity
      08-21 03:48:35.149 7034-7034/? I/zygote: Rejecting re-init on previously-failed class java.lang.Class&lt;com.rayzor536.appointments.MainActivity&gt;: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/support/v7/app/AppCompatActivity;
  08-21 03:48:35.149 7034-7034/? I/zygote: Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v7.app.AppCompatActivity" on path: DexPathList[[zip file "/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/base.apk"],nativeLibraryDirectories=[/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/lib/arm, /system/lib, /system/vendor/lib]]
  08-21 03:48:35.152 7034-7034/? E/AndroidRuntime: FATAL EXCEPTION: main
                                                   Process: com.rayzor536.appointments, PID: 7034
                                                   java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.rayzor536.appointments/com.rayzor536.appointments.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.rayzor536.appointments.MainActivity" on path: DexPathList[[zip file "/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/base.apk"],nativeLibraryDirectories=[/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/lib/arm, /system/lib, /system/vendor/lib]]
                                                       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2680)
                                                       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2857)
                                                       at android.app.ActivityThread.-wrap11(Unknown Source:0)
                                                       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1590)
                                                       at android.os.Handler.dispatchMessage(Handler.java:106)
                                                       at android.os.Looper.loop(Looper.java:164)
                                                       at android.app.ActivityThread.main(ActivityThread.java:6499)
                                                       at java.lang.reflect.Method.invoke(Native Method)
                                                       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:440)
                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
                                                    Caused by: java.lang.ClassNotFoundException: Didn't find class "com.rayzor536.appointments.MainActivity" on path: DexPathList[[zip file "/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/base.apk"],nativeLibraryDirectories=[/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/lib/arm, /system/lib, /system/vendor/lib]]
                                                       at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:125)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
                                                       at android.app.Instrumentation.newActivity(Instrumentation.java:1174)
                                                       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2670)
                                                       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2857) 
                                                       at android.app.ActivityThread.-wrap11(Unknown Source:0) 
                                                       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1590) 
                                                       at android.os.Handler.dispatchMessage(Handler.java:106) 
                                                       at android.os.Looper.loop(Looper.java:164) 
                                                       at android.app.ActivityThread.main(ActivityThread.java:6499) 
                                                       at java.lang.reflect.Method.invoke(Native Method) 
                                                       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:440) 
                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
                                                      Suppressed: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/support/v7/app/AppCompatActivity;
                                                       at java.lang.VMClassLoader.findLoadedClass(Native Method)
                                                       at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:738)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:363)
                                                              ... 12 more
                                                    Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v7.app.AppCompatActivity" on path: DexPathList[[zip file "/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/base.apk"],nativeLibraryDirectories=[/data/app/com.rayzor536.appointments-ijS7lUJ8dmD9B9er-lMpYw==/lib/arm, /system/lib, /system/vendor/lib]]
                                                       at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:125)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
                                                              ... 15 more
  08-21 03:48:35.157 926-5481/? W/ActivityManager:   Force finishing activity com.rayzor536.appointments/.MainActivity
  08-21 03:48:35.173 926-1066/? I/ActivityManager: Showing crash dialog for package com.rayzor536.appointments u0
  08-21 03:48:35.662 926-1065/? W/ActivityManager: Activity pause timeout for ActivityRecord{6e9e3f1 u0 com.rayzor536.appointments/.MainActivity t1469 f}
  08-21 03:48:35.895 926-1416/? I/WindowManager: Failed to capture screenshot of Token{26fabd6 ActivityRecord{6e9e3f1 u0 com.rayzor536.appointments/.MainActivity t1469 f}} appWin=Window{313f14f u0 Splash Screen com.rayzor536.appointments EXITING} drawState=4
  08-21 03:48:42.402 926-5481/? W/ActivityManager:   Force finishing activity com.rayzor536.appointments/.MainActivity
  08-21 03:48:42.404 926-5481/? I/ActivityManager: Killing 7034:com.rayzor536.appointments/u0a137 (adj 900): crash
  </code></pre>
  
  <p>my gradle file is below:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 27
      defaultConfig {
          applicationId "com.rayzor536.appointments"
          minSdkVersion 23
          targetSdkVersion 27
          versionCode 3
          versionName "1.0.2"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
          multiDexEnabled true
      }
      buildTypes {
          release {
              postprocessing {
                  removeUnusedCode false
                  removeUnusedResources false
                  obfuscate false
                  optimizeCode false
                  proguardFile 'proguard-rules.pro'
              }
          }
      }
  }
  
  dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation 'com.android.support:appcompat-v7:27.1.1'
      implementation 'com.android.support.constraint:constraint-layout:1.1.1'
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.2'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
      compile 'com.android.support:multidex:1.0.3'
  }
  </code></pre>
  
  <p>Here is my app manifest:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.rayzor536.appointments"&gt;
  
      &lt;uses-permission android:name="android.permission.INTERNET"/&gt;
  
      &lt;application
          android:allowBackup="true"
          android:icon="@mipmap/ic_launcher"
          android:label="@string/app_name"
          android:roundIcon="@mipmap/ic_launcher_round"
          android:supportsRtl="true"
          android:theme="@style/AppTheme"
          android:name="android.support.multidex.MultiDexApplication"&gt;
          &lt;activity android:name="com.rayzor536.appointments.MainActivity"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
  
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
      &lt;/application&gt;
  
  &lt;/manifest&gt;
  </code></pre>