androidx.appcompat.widget.AppCompatTextView cannot be cast to android.widget.RadioButton修复

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 29584
java.lang.ClassCastException: androidx.appcompat.widget.AppCompatTextView cannot be cast to android.widget.RadioButton
at com.example.myapplication.MainActivity$8.onClick(MainActivity.java:166) at android.view.View.performClick(View.java:4438) at android.view.View$8.onClick(MainActivity.java:166)atandroid.view.View.performClick(View.java:4438)atandroid.view.ViewPerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)

出现这个问题的原因是在RadioGroup标签中有其他的控件，比如TextView

这样就不行，需要把TextView以及其他控件移到RadioGroup标签以外即可，比如：