2022-12-16 00:49:23.504 2669-2669/com.example.bottomnavigation1 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.bottomnavigation1, PID: 2669
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bottomnavigation1/com.example.bottomnavigation1.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View com.google.android.material.bottomnavigation.BottomNavigationView.findViewById(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3685)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3842)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2252)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7842)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View com.google.android.material.bottomnavigation.BottomNavigationView.findViewById(int)' on a null object reference
at com.example.bottomnavigation1.MainActivity.onCreate(MainActivity.java:19)
at android.app.Activity.performCreate(Activity.java:8054)
at android.app.Activity.performCreate(Activity.java:8034)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1 这是logcat的日志
应该是安卓版本的问题，从日志来看是找不到对应的方法，确保你的真机调试版本和本地测试版本保持一致