title: NullPointerException org.chromium.android_webview.AwContents$AwViewMethodsImpl.onDragEvent
body: <p>about 10 days ago, my app started to record this exception (seen on dev console):</p>
  
  <pre><code>java.lang.NullPointerException: 
    at org.chromium.android_webview.AwContents$AwViewMethodsImpl.onDragEvent (AwContents.java:191)
    at com.android.webview.chromium.WebViewChromium.onDragEvent (WebViewChromium.java:782)
    at android.webkit.WebView.onDragEvent (WebView.java:2554)
    at android.view.View.dispatchDragEvent (View.java:22202)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1431)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewGroup.dispatchDragEvent (ViewGroup.java:1417)
    at android.view.ViewRootImpl.handleDragEvent (ViewRootImpl.java:6308)
    at android.view.ViewRootImpl.-wrap11 (ViewRootImpl.java)
    at android.view.ViewRootImpl$ViewRootHandler.handleMessage (ViewRootImpl.java:4199)
    at android.os.Handler.dispatchMessage (Handler.java:102)
    at android.os.Looper.loop (Looper.java:154)
    at android.app.ActivityThread.main (ActivityThread.java:6776)
    at java.lang.reflect.Method.invoke (Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:1496)
    at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1386)
  </code></pre>
  
  <p>I've no idea it could be (so i can't replicate it) and stacktrace covers none of my classes. About this exception I only know that: </p>
  
  <ul>
  <li>effects only devices with android 7 or 7.1 </li>
  <li>first time occurred 11 Oct 2017 </li>
  <li>it occurred about 50 times per days, until 5 Nov 2017 </li>
  <li>it exploded from 6 Nov 2017 until now with about 340 occurrences per day</li>
  </ul>
  
  <p>Users-app-usage is stable from about 1 year (3000 sessions per days, 15minutes per sessions). 
  App is a solitaire card games (no framework as libgdx used).</p>
  
  <p>This is my build.gradle:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  android {
      useLibrary 'org.apache.http.legacy'
      compileSdkVersion 25
      buildToolsVersion '25.0.3'
      defaultConfig {
          applicationId "com.pisano.app.solitari"
          minSdkVersion 15
          targetSdkVersion 23
  
          multiDexEnabled = true
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
          }
          debug {
              signingConfig signingConfigs.config
          }
      }
  
      dexOptions {
          javaMaxHeapSize "4g"
      }
  }
  
  dependencies {
      compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'
      compile project(':pagecontrol')
      compile 'com.facebook.android:facebook-android-sdk:4.26.0'
      compile 'com.google.android.gms:play-services-games:11.2.2'
      compile 'com.google.android.gms:play-services-plus:11.2.2'
      compile 'com.google.android.gms:play-services-analytics:11.2.2'
      compile 'com.google.android.gms:play-services-location:11.2.2'
      compile 'com.google.firebase:firebase-core:11.2.2'
      compile 'com.google.firebase:firebase-ads:11.2.2'
  
  }
  
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>Thank you very much.</p>