尝试在空对象引用上调用虚方法'java.lang.Class java.lang.reflect.Field.getType()'

Question

我在我的Android应用程序中使用activeandroid.

在开发过程中运行调试版本时,一切正常.在创建项目的发布版本后,应用程序现在崩溃了.这种情况发生在带有Android 5.0的Nexus5以及带有Android 4.4.2的Nexus 7上.

如果你需要看一下,这是源代码!
https://github.com/MetalMatze/Krautreporter

谢谢!

java.lang.RuntimeException: Unable to create application com.activeandroid.app.Application: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Class java.lang.reflect.Field.getType()' on a null object reference
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4521)
at android.app.ActivityThread.access$1500(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1339)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
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:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Class java.lang.reflect.Field.getType()' on a null object reference
at com.activeandroid.e.f.c(Unknown Source)
at com.activeandroid.e.f.c(Unknown Source)
at com.activeandroid.f.c(Unknown Source)
at com.activeandroid.f.onCreate(Unknown Source)
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:251)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:163)
at com.activeandroid.b.b(Unknown Source)
at com.activeandroid.b.a(Unknown Source)
at com.activeandroid.a.a(Unknown Source)
at com.activeandroid.a.a(Unknown Source)
at com.activeandroid.a.a(Unknown Source)
at com.activeandroid.app.Application.onCreate(Unknown Source)
at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1011)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4518)
... 9 more

Answer 1

您可以使用反射通过名称查找字段。您的发布版本会被 Proguard/R8 缩小，它将字段重命名为简短而晦涩的名称。您需要向 Proguard/R8 添加一条规则，以保留您使用反射访问的字段名称。

这里已经有关于如何在所有或某些类中保留字段的答案： /sf/answers/1635585101/