java.lang.NoClassDefFoundError：解析失败：Landroidx/appcompat/app/AppCompatActivity

Question

I am developing android lib using androidx kotlin. which i am using other android project which is running on android com.android.support:appcompat-v7:28.0.0, stand alone android lib project runs normaly and other project which I am including AAR file is also working fine. but when I am going to integrate AAR file into other project and calling activity which is present in AAR file then app start crashing

this error massage I am getting

java.lang.NoClassDefFoundError: Failed resolution of: Landroidx/appcompat/app/AppCompatActivity;
        at java.lang.Class.newInstance(Native Method)
        at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69)
        at android.support.v4.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:43)
        at android.app.Instrumentation.newActivity(Instrumentation.java:1232)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2955)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3172)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1906)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6863)
        at java.lang.reflect.Method.invoke(Native Method)

Answer 1

发生这种情况是因为aar文件不包含我们在 gradle 文件中添加的外部依赖项。