IssueTracker

Here is the stacktrace from the provided sample project

```    --------- beginning of crash
2018-05-16 13:39:54.438 29258-29258/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: io.kayvan.io18spike, PID: 29258
    java.lang.RuntimeException: Unable to start activity ComponentInfo{io.kayvan.io18spike/io.kayvan.io18spike.MainActivity}: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class fragment
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2925)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6649)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
     Caused by: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class fragment
     Caused by: android.view.InflateException: Binary XML file line #10: Error inflating class fragment
     Caused by: java.lang.RuntimeException: Exception inflating io.kayvan.io18spike:navigation/nav_graph line 12
        at androidx.navigation.i.a(Unknown Source:124)
        at androidx.navigation.d.a(Unknown Source:4)
        at androidx.navigation.fragment.NavHostFragment.f(Unknown Source:88)
        at android.support.v4.app.h.k(Unknown Source:15)
        at android.support.v4.app.n.a(Unknown Source:367)
        at android.support.v4.app.n.b(Unknown Source:7)
        at android.support.v4.app.n.a(Unknown Source:74)
        at android.support.v4.app.n.onCreateView(Unknown Source:216)
        at android.support.v4.app.k.a(Unknown Source:4)
        at android.support.v4.app.i.a(Unknown Source:2)
        at android.support.v4.app.e.onCreateView(Unknown Source:0)
        at android.support.v4.app.i.onCreateView(Unknown Source:0)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:780)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
        at android.support.v7.app.j.b(Unknown Source:23)
        at android.support.v7.app.c.setContentView(Unknown Source:4)
        at io.kayvan.io18spike.MainActivity.onCreate(Unknown Source:6)
        at android.app.Activity.performCreate(Activity.java:7130)
        at android.app.Activity.performCreate(Activity.java:7121)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1262)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2905)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6649)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
     Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: io.kayvan.io18spike.Fragment2
2018-05-16 13:39:54.439 29258-29258/? E/AndroidRuntime:     at androidx.navigation.fragment.a$a.a(Unknown Source:58)
        at androidx.navigation.fragment.a$a.a(Unknown Source:19)
        at androidx.navigation.i.a(Unknown Source:16)
        at androidx.navigation.i.a(Unknown Source:133)
        at androidx.navigation.i.a(Unknown Source:31)
                ... 36 more
     Caused by: java.lang.ClassNotFoundException: io.kayvan.io18spike.Fragment2
        at java.lang.Class.classForName(Native Method)
        at java.lang.Class.forName(Class.java:453)
        at androidx.navigation.fragment.a$a.a(Unknown Source:45)
                ... 40 more
     Caused by: java.lang.ClassNotFoundException: Didn't find class "io.kayvan.io18spike.Fragment2" on path: DexPathList[[zip file "/system/framework/org.apache.http.legacy.boot.jar", zip file "/data/app/io.kayvan.io18spike-qwaeSphnoJz10eFFCCH9Fw==/base.apk"],nativeLibraryDirectories=[/data/app/io.kayvan.io18spike-qwaeSphnoJz10eFFCCH9Fw==/lib/x86, /system/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)
                ... 43 more```

Thanks, this is definitely something we need to fix. As a workaround, you can manually keep each of the Fragments in your navigation graph if you don't reference them elsewhere.

This has been fixed as part of aapt2 that will ship with the Android Gradle Plugin 3.2 Beta 01.

aapt2 will automatically add keep rules for every android:name attribute found in a Navigation XML file. (This is a similar approach used for the android:name attribute on <fragment> elements in layout XML files.)

Hum, ran into this, as this keeps happening to me..
Gradle plugin 3.5
Navigation 2.1

Re #5 - please file a new issue with a sample project that reproduces your issue.

android.view.InflateException: Binary XML file line #30 in com.example.customnavigation:layout/activity_main: Binary XML file line #30 in com.example.customnavigation:layout/activity_main: Error inflating class com.google.android.material.navigation.NavigationView

Same problem on my side.

same problem
gradle 8.6
AGP 8.2.2
navigation 2.7.7