android studio 运行活动闪退Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'vo-优快云博客

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在修改主页面活动时遇到应用程序崩溃，问题出现在尝试为null对象引用调用Button的setOnClickListener方法。通过检查XML布局文件并确保所有引用正确无误，可以解决此问题。

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Caused by: java.lang.NullPointerException: Attempt to invoke virtual method ‘void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)’ on a null object reference at com.example.mylogin0310.LoginActivity.onCreate(LoginActivity.java:75)

问题描述：FATAL EXCEPTION: main

Process: com.example.mylogin0310, PID: 19367
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mylogin0310/com.example.mylogin0310.LoginActivity}: java.lang.NullPointerException: Attempt to invoke virtual method ‘void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)’ on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2462)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access $800 (A c t i v i t y T h r e a d . j a v a : 167) a t a n d r o i d . a p p . A c t i v i t y T h r e a d$ H.handleMessage(ActivityThread.java:1419)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5546)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit $M e t h o d A n d A r g s C a l l e r . r u n (Z y g o t e I n i t . j a v a : 964) a t c o m . a n d r o i d . i n t e r n a l . o s . Z y g o t e I n i t . m a i n (Z y g o t e I n i t . j a v a : 759) C a u s e d b y : j a v a . l a n g . N u l l P o i n t e r E x c e p t i o n : A t t e m p t t o i n v o k e v i r t u a l m e t h o d^{'} v o i d a n d r o i d . w i d g e t . B u t t o n . s e t O n C l i c k L i s t e n e r (a n d r o i d . v i e w . V i e w$ OnClickListener)’ on a null object reference