我知道这可能太笼统了，看起来像是一个傻瓜的问题。我在开发游戏时遇到问题，似乎找不到问题所在。我会尽量简单地描述这一点
所以我正在创建一个具有多个阶段的单词搜索游戏。有打开页面，关卡地图，其中是用户可以单击的按钮，单词搜索游戏将出现。
问题是，当我单击1级按钮(这是目前唯一有效的按钮(的那一刻，应用程序崩溃了。当我构建它时没有检测到错误，它很快就安装在设备上。
可能出现什么问题？
供参考，这是我的文件 https://github.com/mpdc2510/JavaProject
[编辑] 好的，我按照步骤进行调试，并显示此错误
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.javaproject, PID: 12835
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.javaproject/com.example.javaproject.LondonLevel1}: java.lang.IllegalStateException: congrats_layout must not be null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3271)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3410)
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.ActivityThread$H.handleMessage(ActivityThread.java:2017)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7397)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935)
Caused by: java.lang.IllegalStateException: congrats_layout must not be null
at com.example.javaproject.LondonLevel1.onCreate(LondonLevel1.kt:36)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1300)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3246)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3410)
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.ActivityThread$H.handleMessage(ActivityThread.java:2017)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7397)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935)
I/Process: Sending signal. PID: 12835 SIG: 9
在LondonLevel类中，您调用setContentView(R.layout.activity_main)这似乎是错误的布局。activity_main没有congrats_layoutID。 可能是你想要setContentView(R.layout.activity_level_map)的错误