android - Changing a business object in an Adapter -


i'm building android app similar facebook (gets newsfeed stored in db rest api), , implementing reddit-like voting system, in every feed item has vote state (none, up, down) stored in db.

when retrieve newsfeed json, set votestate vote state in json, display through newsfeed adapter.

but if set votestate in newsfeed adapter value (based on onclicklistener), changed value not reach actual newsfeed. because every time scroll newsfeed, newsfeed adapter gets new instance of newsfeed, , doesn't care value changed.

thus, i'm looking best way modify permanently newsfeed vote state newsfeed adapter (this can generalized variable assigned arraylist , displayed through arraylistadapter).

if have suggestions, please feel free respond.

thank :)

edit : 

public class newsfeedadapter extends recyclerview.adapter<newsfeedadapter.viewholder> {  private newsfeed newsfeed; private feeditem item;  public newsfeedadapter(..., newsfeed newsfeed) {     ...;     this.newsfeed = newsfeed; }  public static class viewholder extends recyclerview.viewholder {     protected button button_up/down....      public viewholder(view v) {         super(v);          button = findviewbyid ... (r.id.button);         ...     }  }  // create new views (invoked layout manager) @override public viewholder oncreateviewholder(viewgroup viewgroup, int viewtype) {     ... }  @override public void onbindviewholder(final viewholder holder, final int position) {     final feeditem item = newsfeed.get(position);      holder.button_up.settag(position);     holder.button_up.setonclicklistener(new view.onclicklistener() {         @override         public void onclick(view v) {             changevote(item, "up");         }     });      holder.button_down.settag(position);     holder.button_down.setonclicklistener(new view.onclicklistener() {         @override         public void onclick(view v) {             changevote(item, "down");         }     }); }  public void changevote(feeditem item, string flag) {     // log.d(tag, "state of vote :" + item.getvotestate());     if (item.getvotestate().equals(flag)) {         item.setvotestate("none");         log.d(tag, "deleting vote :" + item.getvotestate());         new connexion(activity, fragment, "vote", "deleting vote...").execute(string.valueof(item.getid()), flag, "delete");     }     else if (item.getvotestate().equals("none")){         item.setvotestate(flag);         log.d(tag, "voting :" + item.getvotestate());         new connexion(activity, fragment, "vote", "voting...").execute(string.valueof(item.getid()), flag, "insert");      } else {         item.invertvotestate(flag);         log.d(tag, "inverting :" + item.getvotestate());         new connexion(activity, fragment, "vote", "voting...").execute(string.valueof(item.getid()), flag, "invert");     } } }

you have 2 options:

1) send updates rest api every time piece of data changed. expensive , not want likely.

2) create local data layer between rest api , listview - sqlite database or other orm lib. way can hold instance of db in adapter, , whenever piece of data changes, can update through simple db method call, , periodically send updates rest api, while checking new updates rest api , pushing them db.

i highly recommend using sqlite db, can keep counter in db code of number of changes, or time passed since last sync, , keep data user seeing date out smashing users data usage repeated network calls.


Comments

Post a Comment

Popular posts from this blog

c++ - Difference between pre and post decrement in recursive function argument -

i have following sample code used pre-decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(--c); cout << c << endl; return; } } this function give output input 4 : dp3 dp2 dp1 dp0 0 1 2 3 but when use post decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(c--); cout << c << endl; return; } } output goes in infinite loop dp4 can explain me in detail why happens ? this happens because function(c--) called same value of c , when finishes c decremented. recursively called, hence called same value no chance of return , hit stack overflow error. assume this, int x = 1, y = 0; y = x++ result y == 1 , x == 2. if y = ++x , bot x , y 2.
Read more

php - Nothing but 'run(); ' when browsing to my local project, how do I fix this? -

i added new project. made mistake in projectname.conf file in sites-available apache2, led me reinstalling apache2. after reinstalling , re-enabling projects on every page of every project .. <body> run(); </body> .. i've run composer update, restarted service, restarted pc, checked config files, tried disabling new project. there nothing in error log, , access.log: 127.0.0.1 - - [15/may/2015:01:40:47 +0200] "get / http/1.1" 304 181 "-" "mozilla/5.0 (x11; ubuntu; linux x86_64; rv:38.0) gecko/20100101 firefox/38.0" maybe i'm forgetting apache2 reinstall? don't think did different last time installed it. looks haven't setup php correctly. take @ this great guide , maybe you're forgetting link php config apache2.
Read more

php - How can I echo out this array? -

i don't know how go grabbing data in variable , put foreach loop. class tree{ private $info = array( array('name'=>'jim','state'=>'nu','company'=>'nu','phone'=>array('cell'=>'5615111111','office'=>'5611111111'),'email'=>array('primary'=>'exs@example.com','ex@there.com')), array('name'=>'joe smith','city'=>'phoenix','phone'=>'4805551111','email'=>'jsmith@some_email.com'), array('name'=>'john doe','city'=>'chandler','company'=>'doe co.','email'=>array('jdoe@gmail.com','personal'=>'email@email.com'),'phone'=>'6025550002') ); } if you're inside of class, can access private variable using $this->variablename . example, i...
Read more