flow-sample app crashes when launched on a tablet in landscape mode about flow HOT 3 CLOSED

Oops. Thanks for the report, will dig into it.

On Mon, Apr 27, 2015, 8:11 PM Prashanth Sadasivan [email protected]
wrote:

Hey, I was just poking around the sample, trying to better understand how
flow works. I built the flow-sample app, and it seems to work just fine in
portrait mode, but in landscape mode, when the MasterPathContainerView is
used, the app crashes on startup.

Here's the stack trace:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.flow/com.example.flow.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'flow.History flow.Flow.getHistory()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'flow.History flow.Flow.getHistory()' on a null object reference
at com.example.flow.pathview.MasterPathContainerView.dispatch(MasterPathContainerView.java:21)
at com.example.flow.view.TabletMasterDetailRoot.dispatch(TabletMasterDetailRoot.java:76)
at com.example.flow.MainActivity.dispatch(MainActivity.java:146)
at flow.Flow$PendingTraversal.dispatch(Flow.java:315)
at flow.Flow$1.doExecute(Flow.java:141)
at flow.Flow$PendingTraversal.execute(Flow.java:323)
at flow.Flow.move(Flow.java:232)
at flow.Flow.setHistory(Flow.java:139)
at flow.Flow.setDispatcher(Flow.java:107)
at flow.FlowDelegate.onCreate(FlowDelegate.java:104)
at com.example.flow.MainActivity.onCreate(MainActivity.java:72)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)

I haven't changed any source files, just the gradle-mvn-push.gradle file
to get rid of some gradle warnings (missing POM_DEVELOPER_ID). I tried
digging into it for an hour or so, but I couldn't find a trivial solution
to the problem. Am I doing anything wrong?

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#82.

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Awesome, thanks a ton. I figured out why it's occurring. FlowDelegate.onCreate triggers a traversal, which eventually yields a Flow.get(getContext()) in MasterPathContainerView. But since we're still creating the FlowDelegate, the MainActivity's flowSupport field is null, which causes the call to Flow.get() to return null in the MasterPathContainerView. Unfortunately I wasn't sure what the intent was of that code, so I couldn't figure out a fix for it. Hope that helps!

from flow.

(MainActivity.java:146)
I'm facing this error plz help to resolve it

from flow.