sql - Android LoadMore-ListView -

i have internal-database(sqlite) many entries. decided load first 20 entries in listview when user starts activity , when scrolls down can load 20 more each time pressing button if there entries left.

edit

//oncreate() acceptedlogs = helper.getlogsrange(0, load_amount);         loadedentriescounter = load_amount;          logadapter = new logadapter(acceptedlogs);         logrecyclerview.setadapter(logadapter);         logrecyclerview.sethasfixedsize(false);         linearlayoutmanager = new linearlayoutmanager(getcontext());         logrecyclerview.setlayoutmanager(linearlayoutmanager);     @override             public void onscrolled(recyclerview recyclerview, int dx, int dy) {                 super.onscrolled(recyclerview, dx, dy);                 visibleitemcount = logrecyclerview.getchildcount();                 totalitemcount = logrecyclerview.getlayoutmanager().getitemcount();                 int firstvisibleitemposition = linearlayoutmanager.findfirstvisibleitemposition();                 if (loading) { // boolean set true if loading , false after update adaptor                     if (totalitemcount > previoustotalcount) {                         previoustotalcount = totalitemcount;                     }                 }                 if (!loading && (totalitemcount - visibleitemcount) <= (firstvisibleitemposition + visible_threshold)) {                     loading = true;                     list<log> newlogs = helper.getlogsrange(loadedentriescounter, load_amount);                     loadedentriescounter += load_amount;                     logadapter.logs.addall(newlogs);                     logadapter.notifydatasetchanged();                  }             } 

the loading happens ones! have set loading on false?

first, better use recyclerview viewholder, second better load data on scroll listener , trick, example have loaded 20 items when scroll list there load data when scroll list , scrolled example 18 item @ bottom, here start async task , when scroll 20 loading finish , update list 20 more user not see when loading.

mvisiblethreshold = 2 // count items bottom of current list when load start. 

here on scroll listener recyclerview (can adjusted listview):

mproductsresultslist.setonscrolllistener(new recyclerview.onscrolllistener() {             @override             public void onscrollstatechanged(recyclerview recyclerview, int newstate) {                 super.onscrollstatechanged(recyclerview, newstate);             }              @override             public void onscrolled(recyclerview recyclerview, int dx, int dy) {                   super.onscrolled(recyclerview, dx, dy);                 mvisibleitemcount = mproductsresultslist.getchildcount();                 mtotalitemcount = mproductsresultslayoutmanager.getitemcount();                 mfirstvisibleitem = mproductsresultslayoutmanager.findfirstvisibleitemposition();                  if (mloadinginprogress) { // boolean set true if loading , false after update adaptor                     if (mtotalitemcount > mprevioustotal) {                          mprevioustotal = mtotalitemcount;                     }                 }                 if (!mloadinginprogress && (mtotalitemcount - mvisibleitemcount)                         <= (mfirstvisibleitem + mvisiblethreshold)) {                     mloadinginprogress = true;                         mlastpagerequest++; // current page load , add                         // here load data , update adapter                         // if in async task start here , set mloadinginprogress true , onpostexecute add list result , make notifydatasetchanged on adapter mloadinginprogress false.                   }             }         }); 

one more: don't touch views in background tasks (otherwise stuck main thread), make updates , notifications after task code in onpostexecute runonuithread.

okay interested in solution improve answer:

mlastpagerequest - int use know page loaded , must load next it's incrementing each time 1 ++

after loading data (from database or web request should add downloaded items list). in project list "mcategoryproducts" , adapter mproductsresultslistadapter.

all u need add next items downloaded list attached adapter

mcategoryproducts.addall(downloadedlistproducts); // here adding items loaded existing list end,  

now next code:

public void displaygotresults(){         if(mcategoryproducts != null){             if(mproductsresultslistadapter == null && mlastpagerequest==1){                 mproductsresultslistadapter = new productlistrecyclerviewadapter(this, mcategoryproducts, true);                 mproductsresultslist.setadapter(mproductsresultslistadapter);                 mproductsresultslistadapter.setclicklistener(this);             }else{                 mproductsresultslistadapter.notifydatasetchanged();                 //notifyiteminserted(msearchlist.size()-1);             }             if(mcategoryproducts.size()>0) {                 mcategoryisemptyinfo.setvisibility(view.gone);             }else{                 mcategoryisemptyinfo.setvisibility(view.visible);             }         }else{             mcategoryisemptyinfo.setvisibility(view.visible);         }     } 

here if adapter not initialised create , attaching our list mcategoryproducts otherwise if second loading simple notify adapter "hey man new data comming :)" with:

mproductsresultslistadapter.notifydatasetchanged(); 

notes: mcategoryisemptyinfo - view show when there no items display.

here custom adaptor interface clicks can handled in activity )

public class productlistrecyclerviewadapter extends recyclerview.adapter<productlistrecyclerviewadapter.productlistrecyclerviewholder> {     private layoutinflater minflater;     private context mcontext;     private drawerlayout mnavigationdrawer;     private clicklistener mclicklistener;     private longclicklistener mlongclicklistener;     list<productmodel> navigationdata = collections.emptylist();     private imageloader mimageloader;     private volleyservicesingleton mvollayservice;     private boolean mshowthumbnail;      //for animations     private int mlastpositiion = -1;      public productlistrecyclerviewadapter (context context, list<productmodel> navdata, boolean showthumbnail){         minflater = layoutinflater.from(context);         this.navigationdata = navdata;         mcontext = context;         mvollayservice = volleyservicesingleton.getinstance();         mimageloader = mvollayservice.getimageloader();         mshowthumbnail = showthumbnail;     }       @override     public productlistrecyclerviewholder oncreateviewholder(viewgroup parent, int viewtype) {         view view = minflater.inflate(r.layout.list_item_product, parent, false);         productlistrecyclerviewholder holder = new productlistrecyclerviewholder(view);         return holder;     }      @override     public void onbindviewholder(final productlistrecyclerviewholder viewholder, int position) {         productmodel currentitem = navigationdata.get(position);         viewholder.productbrand.settext(currentitem.manufacturername);         viewholder.productname.settext(currentitem.name);         viewholder.productcode.settext(currentitem.code);         viewholder.productprice.settext(string.format(mcontext.getstring(r.string.money_sign), utils.decimalwithcommas(string.valueof(currentitem.dealerprice))));          if(constants.show_image_thumbnails_in_list && mshowthumbnail){             if(currentitem.catalogimage != null && currentitem.catalogimage.contains("http")){                 viewholder.productthumbnail.setvisibility(view.visible);                 mimageloader.get(currentitem.catalogimage, new imageloader.imagelistener() {                     @override                     public void onresponse(imageloader.imagecontainer response, boolean isimmediate) {                         viewholder.productthumbnail.setimagebitmap(response.getbitmap());                     }                      @override                     public void onerrorresponse(volleyerror error) {                      }                 });             }         }else{             viewholder.productthumbnail.setvisibility(view.gone);         }      }      public void setanimation(view viewtoanimate, int position)     {         // if bound view wasn't displayed on screen, it's animated         if (position > mlastpositiion)         {             animation animation = animationutils.loadanimation(mcontext, android.r.anim.slide_in_left);             viewtoanimate.startanimation(animation);             mlastpositiion = position;         }     }     @override     public int getitemcount() {         return navigationdata.size();     }      public void setclicklistener(clicklistener clicklistener){         this.mclicklistener = clicklistener;     }     public void setlongclicklistener(longclicklistener lognclicklistener){         this.mlongclicklistener = lognclicklistener;     }       public class productlistrecyclerviewholder extends recyclerview.viewholder implements view.onclicklistener, view.onlongclicklistener{         textview productbrand;         textview productname;         textview productcode;         textview productprice;         imageview productthumbnail;         public productlistrecyclerviewholder(view itemview) {             super(itemview);             productbrand = (textview) itemview.findviewbyid(r.id.product_brand);             productname = (textview) itemview.findviewbyid(r.id.product_name);             productcode = (textview) itemview.findviewbyid(r.id.product_code);             productprice = (textview) itemview.findviewbyid(r.id.product_price);             productthumbnail = (imageview) itemview.findviewbyid(r.id.product_thumbnail);             itemview.setonclicklistener(this);             itemview.settag(this);             itemview.setonlongclicklistener(this);          }          @override         public void onclick(view v) {             if(mclicklistener!=null){                 mclicklistener.itemclicked(v, getadapterposition());             }         }          @override         public boolean onlongclick(view v) {             if(mlongclicklistener!=null){                 mlongclicklistener.itemlongclicked(v, getadapterposition());             }             return false;         }     }     public interface clicklistener{         void itemclicked(view view, int position);     }      public interface longclicklistener{         void itemlongclicked(view view, int position);     } } 

it not work without update needs, nice sample how must )

make attention on

mproductsresultslistadapter.setclicklistener(this); 

then in activity can catch clicks :

public class productlistactivity extends actionbaractivity implements productlistrecyclerviewadapter.clicklistener {      //.....      @override     public void itemclicked(view view, int position) {      }      //..... } 

one more thing if need catch click example on specific view in item in list example on image in view holder set click listener "this" , set tag view , in activity can tag view , know clicked :)

your loading database:

 loading = true;                     list<log> newlogs = helper.getlogsrange(loadedentriescounter, load_amount);                     loadedentriescounter += load_amount;                     logadapter.logs.addall(newlogs);  loading = false; // somewhere here  

but not correct way load data can stuck main thread coz if database big or make "heavy" selection can stuck several milisec. must data loading in async tasks , on task done notify adapter.

in project load data webapi, not database in anyway must done in same way via async task, proper way )

class loadnextpagetask extends asynctask<integer, void, list<productmodel>> {         int pagetoload;          public loadnextpagetask(int pagetoload){             this.pagetoload = pagetoload;         }           @override         protected list<productmodel> doinbackground(integer... params) {             return helper.getlogsrange(loadedentriescounter, load_amount); // here apply page load??? not sure         }          @override         protected void onpreexecute() {             mmainloadingprogress.setvisibility(view.visible);             loading = true;         }          @override         protected void onpostexecute(list<productmodel> newlogs) {             loading = false;             loadedentriescounter += load_amount;             logadapter.logs.addall(newlogs);              runonuithread(new runnable() {                 @override                 public void run() {                     logadapter.notifydatasetchanged();                 }             });             mmainloadingprogress.setvisibility(view.gone);          }     } 

above async task please update needs data loading simple start with:

new loadnextpagetask(pagenumber).execute(); // page int