Back Button Crashes App

[pedroliman]

The app crashes when the ActionBar's back button is pressed in PlaceActivity.
Apparently this has something to do with the Activity's intent:
Android Logged Callstack:

FATAL EXCEPTION: main
                                                                             Process: org.avaliabrasil.avaliabrasil, PID: 3107
                                                                             java.lang.RuntimeException: Unable to start activity ComponentInfo{org.avaliabrasil.avaliabrasil/org.avaliabrasil.avaliabrasil.MainActivity}: java.lang.NullPointerException
                                                                                 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2279)
                                                                                 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2329)
                                                                                 at android.app.ActivityThread.access$800(ActivityThread.java:145)
                                                                                 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
                                                                                 at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                 at android.os.Looper.loop(Looper.java:136)
                                                                                 at android.app.ActivityThread.main(ActivityThread.java:5214)
                                                                                 at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                 at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:814)
                                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:630)
                                                                                 at dalvik.system.NativeStart.main(Native Method)
                                                                              Caused by: java.lang.NullPointerException
                                                                                 at org.avaliabrasil.avaliabrasil.MainActivity.onCreate(MainActivity.java:78)
                                                                                 at android.app.Activity.performCreate(Activity.java:5231)
                                                                                 at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
                                                                                 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2243)
                                                                                 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2329) 
                                                                                 at android.app.ActivityThread.access$800(ActivityThread.java:145) 
                                                                                 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265) 
                                                                                 at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                                 at android.os.Looper.loop(Looper.java:136) 
                                                                                 at android.app.ActivityThread.main(ActivityThread.java:5214) 
                                                                                 at java.lang.reflect.Method.invokeNative(Native Method) 
                                                                                 at java.lang.reflect.Method.invoke(Method.java:515)

The callstack points to this line in MainActivity.java:

        userId = getIntent().getExtras().getInt(USRID);
        Toast.makeText(this,"Id de Usuário : " + userId,Toast.LENGTH_SHORT).show();`

Maybe passing the userId on the intent is not a good practice.