[JAVA] Ich habe eine Frage zu Android Studio.

Ich erstelle meine eigene Android-App, aber wenn ich die App starte, heißt es, dass sie wiederholt gestoppt wird und nicht funktioniert. Ich habe Logcat überprüft, aber es wird wie folgt angezeigt. Es ist nicht gut verstanden. Wie kann ich es reparieren?

2020-07-10 22:39:52.674 17730-17730/? E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.fumemo, PID: 17730 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.fumemo/com.example.fumemo.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3194) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThreadH.handleMessage(ActivityThread.java:2016) at android.os.Handler.dispatchMessage(Handler.java:107) at android.os.Looper.loop(Looper.java:214) at android.app.ActivityThread.main(ActivityThread.java:7356) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInitMethodAndArgsCaller.run(RuntimeInit.java:492) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:163) at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:174) at android.content.Context.obtainStyledAttributes(Context.java:738) at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:692) at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:659) at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:479) at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:214) at com.example.fumemo.MainActivity.(MainActivity.java:35) at java.lang.Class.newInstance(Native Method) at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95) at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:41) at android.app.Instrumentation.newActivity(Instrumentation.java:1250) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3182) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)  at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)  at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)  at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)  at android.app.ActivityThreadH.handleMessage(ActivityThread.java:2016)  at android.os.Handler.dispatchMessage(Handler.java:107)  at android.os.Looper.loop(Looper.java:214)  at android.app.ActivityThread.main(ActivityThread.java:7356)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.RuntimeInitMethodAndArgsCaller.run(RuntimeInit.java:492)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)