在将NavigationComponent（android.arch.navigation:navigation-fragment-ktx:1.0.0-alpha01）集成到我的项目中并使用目标和编译SDK为27 后，使用proguard时遇到了崩溃
2018-05-16 12:13:14.044 24573-24573/com.mypackage.myapp.x E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mypackage.myapp.x, PID: 24573
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mypackage.myapp.x/com.mypackage.myapp.MainActivity}: android.view.InflateException: Binary XML file line #16: Binary XML file line #16: 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 #16: Binary XML file line #16: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #16: Error inflating class fragment
Caused by: java.lang.RuntimeException: Exception inflating com.mypackage.myapp.x:navigation/nav_graph line 7
at androidx.navigation.j.a(Unknown Source:124)
at androidx.navigation.d.a(Unknown Source:4)
at androidx.navigation.fragment.NavHostFragment.a(Unknown Source:88)
at android.support.v4.app.Fragment.l(Unknown Source:15)
at android.support.v4.app.m.a(Unknown Source:369)
at android.support.v4.app.m.b(Unknown Source:7)
at android.support.v4.app.m.a(Unknown Source:74)
at android.support.v4.app.m.onCreateView(Unknown Source:216)
at android.support.v4.app.j.a(Unknown Source:4)
at android.support.v4.app.h.a(Unknown Source:2)
at android.support.v4.app.d.onCreateView(Unknown Source:0)
at android.support.v4.app.h.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.rInflate(LayoutInflater.java:866)
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.AppCompatDelegateImplV9.b(Unknown Source:23)
at android.support.v7.app.d.setContentView(Unknown Source:4)
at com.mypackage.myapp.MainActivity.onCreate(Unknown Source:12)
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$H.handleMessage(ActivityThread.java:1800)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6649)
at java.lang.reflect.Method.invoke(Native Method)
2018-05-16 12:13:14.044 24573-24573/com.mypackage.myapp.x E/AndroidRuntime: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: com.mypackage.myapp.fragments.MainFragment
at androidx.navigation.fragment.b$a.a(Unknown Source:58)
at androidx.navigation.fragment.b$a.a(Unknown Source:19)
at androidx.navigation.j.a(Unknown Source:16)
at androidx.navigation.j.a(Unknown Source:133)
at androidx.navigation.j.a(Unknown Source:31)
... 38 more
Caused by: java.lang.ClassNotFoundException: com.mypackage.myapp.fragments.MainFragment
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:453)
at androidx.navigation.fragment.b$a.a(Unknown Source:45)
... 42 more
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.mypackage.myapp.fragments.MainFragment" on path: DexPathList[[zip file "/system/framework/org.apache.http.legacy.boot.jar", zip file "/data/app/com.mypackage.myapp.x-ysts055HQTtJTv5J2uej3g==/base.apk"],nativeLibraryDirectories=[/data/app/com.mypackage.myapp.x-ysts055HQTtJTv5J2uej3g==/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)
... 45 more
可能是因为AAPT尚未为导航组件生成保留规则？
我知道Proguard和R8应该保留所有库类的子类，但是在这种情况下，片段类似乎丢失了。该保留规则解决了我的问题，但从技术上讲，我们根本不需要此规则！
-keep class * extends android.support.v4.app.Fragment{}
如果您使用的是AndroidX，请使用以下规则： -keep class * extends androidx.fragment.app.Fragment{}
如果argType在导航XML中使用，则还需要为所引用的类指定规则，例如：-keep class com.example.model.MyModel。甚至更好的是，按照官方文档的建议，将可打包和可序列化的类排除在重命名之外。 -keepnames class * extends android.os.Parcelable -keepnames class * extends java.io.Serializable
本文收集自互联网，转载请注明来源。
如有侵权，请联系 [email protected] 删除。
我来说两句