As an alternative, why not store the ArrayList<Student> in the Application object, and have getArrayList<Student> and setArrayList<Student> methods. The Fragment can access the ArrayList<Student> and update ArrayList<Student> with these methods. Since the Application object is a singelton, there will only be one valid copy of ArrayList<Student>.
Mark On Fri, Dec 4, 2015 at 1:20 AM, Doug <[email protected]> wrote: > > > On Thursday, December 3, 2015 at 8:03:24 PM UTC-8, TreKing wrote: >> >> >> On Thu, Nov 26, 2015 at 12:35 AM, Vinayak Mestri <[email protected]> >> wrote: >> >>> I want to do like above code i.e student is reference variable so if i >>> change any values of student arraylist will reflect to actual object in >>> activity >> >> >> 1 - Look at the documentation for Fragment which shows the static >> constructor pattern that is typically used to construct a fragment with >> parameters. >> http://developer.android.com/reference/android/app/Fragment.html >> Your model object would implement the Parcelable interface to be passed >> along as data. >> >> 2 - You can then let the Activity know when changes are made via >> callbacks: >> >> http://developer.android.com/guide/components/fragments.html#CommunicatingWithActivity >> >> You generally don't want the exact same data object in the activity and >> fragment. >> > > You generally *do* want the exact same data object if the object is large > and would take significant time and memory to serialize and deserialize in > a fully duplicated form. This is especially OK if your source object is > immutable and therefore threadsafe and immune to tampering for read > operations. > > >> If you really really do, you could alternative expose it as a public >> method in the Activity then instead of passing it to the fragment, access >> your activity in the fragment (onAttach or onActivityCreated or something) >> and get the list data, which would be the actual list both objects would >> share. >> > > Also, if serialization is not a well-performing option, sending the > fragment an indicator on how to find the collection would be fine. > Sometimes people use an event bus to publish stored data object to > dependents. Sometimes receiving from a singleton is good enough as long as > it's not adding too much weight to the app. Sometimes querying a content > provider (backed by sqlite database) for very large collections is > appropriate. > > Doug > > -- > You received this message because you are subscribed to the Google Groups > "Android Developers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/android-developers. > To view this discussion on the web visit > https://groups.google.com/d/msgid/android-developers/a903fbfa-9b30-4941-a94f-4831c310686c%40googlegroups.com > <https://groups.google.com/d/msgid/android-developers/a903fbfa-9b30-4941-a94f-4831c310686c%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/android-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/android-developers/CAEqej2M%2BeRAmB%3Dt751F7qGPw8Mx9ewZMAdsMDpJdiDpGF4haJg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
