android - Alternative way for Fragment to Activity communication -

-

note, official way fragment activity communication, according http://developer.android.com/training/basics/fragments/communicating.html

public class headlinesfragment extends listfragment {     onheadlineselectedlistener mcallback;      // container activity must implement interface     public interface onheadlineselectedlistener {         public void onarticleselected(int position);     }      @override     public void onattach(activity activity) {         super.onattach(activity);          // makes sure container activity has implemented         // callback interface. if not, throws exception         try {             mcallback = (onheadlineselectedlistener) activity;         } catch (classcastexception e) {             throw new classcastexception(activity.tostring()                     + " must implement onheadlineselectedlistener");         }     }      @override     public void onlistitemclick(listview l, view v, int position, long id) {         // send event host activity         mcallback.onarticleselected(position);     } }

however, had came across code performs following technique.

    @override     public void onlistitemclick(listview l, view v, int position, long id) {         // send event host activity         ((onheadlineselectedlistener)this.getactivity()).onarticleselected(position);     }

i tested far works, after configuration change, still latest activity.

i wondering, there catch behind method, besides method recommended google? instance, can getactivity return null?

you should fine second way - first way "shortcut", stores activity in local variable instead of "fetching" via getactivity() each time used.


Comments

Post a Comment

Popular posts from this blog

android - Why am I getting the message 'Youractivity.java is not an activity subclass or alias' -

-
Image
i created own android project , cut , pasted code exercise: http://androidexample.com/show_phone_contacts_in_autocomplete_suggestions_-_android_example%20/index.php?view=article_discription&aid=106&aaid=128# when build project no errors or warnings. when run project window error: annoyingly, can't make window smaller, can't click of buttons. cick 'x' @ top, close it. here's project structure: where getting 'autocompletemain' from? (note small c) class named autocompletemain. help. and have activity included in android manifest, in case you're wondering: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.androidexample.autocompleteedittext" android:versioncode="1" android:versionname="1.0" > <uses-permission android:name="android.permission.read_phone_state...
Read more

python - How do I create a list index that loops through integers in another list -

-
i have list: sentences = ['the number of adults read @ least 1 novel within past 12 months fell 47%.', 'fiction reading rose 2002 2008.', 'the decline in fiction reading last year occurred among men.', 'women read more fiction.', '50% more.', 'though decreased 10% on last decade.', 'men more read nonfiction.', 'young adults more read fiction.', 'just 54% of americans cracked open book of kind last year.', 'but novels have suffered more nonfiction.'] and have list containing indexes of sequences of sentences in above list contain number. index_groupings = [[0, 1], [4, 5], [8]] i want extract specified sentence sequences in variable "sentences" using indexes in variable "index_groupings" following output: the number of adults read @ least 1 novel within past 12 months fell 47%.fiction reading rose 2002 2008. 50% more.though decreased 10% on last decade. just 54% of a...
Read more

c# - “System.Security.Cryptography.CryptographicException: Keyset does not exist” when reading private key from remote machine -

-
i trying decrypt data using certificate private key. works fine when certificate installed on local machine (i using self signed certificate testing , have private key certificate) when try access private key remote machine using same code, "keyset not exist" exception. i using console application testing, , have made sure id have read permissions on private key on remote server. here sample code using: var store = new x509store(@"\\server1\my", storelocation.localmachine); store.open(openflags.readonly); var result = store.certificates.find(x509findtype.findbysubjectname, "server1.test.com", false); var certificate = result[0]; store.close(); //this succeeds both local , remote server var rsapublic = (rsacryptoserviceprovider)certificate.publickey.key; //this succeeds local, fails remote server var rsaprivate = (rsacryptoserviceprovider)certificate.privatekey; here exception call stack unhandled exception: system.security.cryptography.crypto...
Read more