我的应用程序崩溃来自Google Play cosole的报告

Question

我是Android开发的新手。我开发了一个应用程序并将其发布到谷歌播放但最近我发现崩溃报告，因为许多崩溃发生在代码的特定部分，如下所示。我想不明白。

java.lang.RuntimeException: 
 at android.app.ActivityThread.performLaunchActivity 
 (ActivityThread.java:2643)
 at android.app.ActivityThread.handleLaunchActivity 
 (ActivityThread.java:2709)
 at android.app.ActivityThread.access$1000 (ActivityThread.java:196)
 at android.app.ActivityThread$H.handleMessage 
 (ActivityThread.java:1534)
 at android.os.Handler.dispatchMessage (Handler.java:111)
 at android.os.Looper.loop (Looper.java:207)
 at android.app.ActivityThread.main (ActivityThread.java:5867)
 at java.lang.reflect.Method.invoke (Native Method)
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run 
 (ZygoteInit.java:1026)
 at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:887)
Caused by: java.lang.NullPointerException: 
 at local.app.user.myapp.MainActivity.onCreate 
 (MainActivity.java:154)
 at android.app.Activity.performCreate (Activity.java:6285)
 at android.app.Instrumentation.callActivityOnCreate   ( 
 Instrumentation.java:1119)
 at android.app.ActivityThread.performLaunchActivity 
 (ActivityThread.java:2596)