java - Issues in Recycler view when retrive the data from using json -
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my issue when creating recycler view using json shows exception 1 can solve issue u r brilliance please me solve issue , appreciate solve error?
public class mainactivity extends activity { button b; textview tv; listview lists; recyclerview recyclerview; list<your> yourss; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); recyclerview = (recyclerview) findviewbyid(r.id.recycle); linearlayoutmanager ll = new linearlayoutmanager(mainactivity.this); recyclerview.sethasfixedsize(true); recyclerview.setlayoutmanager(ll); new jsontask().execute("http://yoursubshop.com/webservices/categories.php"); } public class jsontask extends asynctask<string, string, list<your>> { @override protected list<your> doinbackground(string... params) { httpurlconnection httpurlconnection = null; bufferedreader bufferedreader = null; try { url url = new url(params[0]); httpurlconnection = (httpurlconnection) url.openconnection(); inputstreamreader inputstreamreader = new inputstreamreader(httpurlconnection.getinputstream()); bufferedreader = new bufferedreader(inputstreamreader); stringbuffer sb = new stringbuffer(); string line = ""; while ((line = bufferedreader.readline()) != null) { sb.append(line); } string finaljson = sb.tostring(); jsonobject firstobject = new jsonobject(finaljson); jsonarray firstarray = firstobject.getjsonarray("data"); list<your> yo = new arraylist<>(); (int = 0; < firstarray.length(); i++) { jsonobject finalobject = firstarray.getjsonobject(i); yos = new your(); yos.category_id = finalobject.getstring("category_id"); yos.category_name = finalobject.getstring("category_name"); yo.add(yos); } return yo; } catch (malformedurlexception e) { e.printstacktrace(); } catch (ioexception e) { e.printstacktrace(); } catch (jsonexception e) { e.printstacktrace(); } { if (httpurlconnection != null) { httpurlconnection.disconnect(); } try { if (bufferedreader != null) { bufferedreader.close(); } } catch (ioexception e) { e.printstacktrace(); } } return null; } @override protected void onpostexecute(list<your> result) { super.onpostexecute(result); rvadapter listadapter = new rvadapter(mainactivity.this, yourss); recyclerview.setadapter(listadapter); } } public class rvadapter extends recyclerview.adapter<rvadapter.myadapter> { list<your> yours = collections.emptylist(); context c; public class myadapter extends recyclerview.viewholder { textview id; textview name; cardview cv; public myadapter(view itemview) { super(itemview); id = (textview) itemview.findviewbyid(r.id.texts); name = (textview) itemview.findviewbyid(r.id.textsa); cv = (cardview)itemview.findviewbyid(r.id.card); } } public rvadapter(context c, list<your> yours) { this.yours = yours; this.c = c; } @override public myadapter oncreateviewholder(viewgroup parent, int viewtype) { view v = layoutinflater.from(parent.getcontext()).inflate(r.layout.lists, parent, false); myadapter m = new myadapter(v); return m; } @override public void onbindviewholder(myadapter holder, int position) { y = yours.get(position); holder.id.settext(y.category_id); holder.name.settext(y.category_name); } @override public int getitemcount() { return yours.size(); } @override public void onattachedtorecyclerview(recyclerview recyclerview) { super.onattachedtorecyclerview(recyclerview); } } eception in programme
06-28 17:03:34.078 802-802/com.example.anilkumar.json e/androidruntime: fatal exception: main java.lang.nullpointerexception @ com.example.anilkumar.json.mainactivity$rvadapter.getitemcount(mainactivity.java:154) @ android.support.v7.widget.recyclerview.dispatchlayoutstep1(recyclerview.java:3170) @ android.support.v7.widget.recyclerview.onmeasure(recyclerview.java:2782) @ android.view.view.measure(view.java:12723) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4698) @ android.widget.linearlayout.measurechildbeforelayout(linearlayout.java:1369) @ android.widget.linearlayout.measurevertical(linearlayout.java:660) @ android.widget.linearlayout.onmeasure(linearlayout.java:553) @ android.view.view.measure(view.java:12723) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4698) @ android.widget.framelayout.onmeasure(framelayout.java:293) @ android.view.view.measure(view.java:12723) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4698) @ android.widget.linearlayout.measurechildbeforelayout(linearlayout.java:1369) @ android.widget.linearlayout.measurevertical(linearlayout.java:660) @ android.widget.linearlayout.onmeasure(linearlayout.java:553) @ android.view.view.measure(view.java:12723) @ android.view.viewgroup.measurechildwithmargins(viewgroup.java:4698) @ android.widget.framelayout.onmeasure(framelayout.java:293) @ com.android.internal.policy.impl.phonewindow$decorview.onmeasure(phonewindow.java:2092) @ android.view.view.measure(view.java:12723) @ android.view.viewrootimpl.performtraversals(viewrootimpl.java:1064) @ android.view.viewrootimpl.handlemessage(viewrootimpl.java:2442) @ android.os.handler.dispatchmessage(handler.java:99) @ android.os.looper.loop(looper.java:137) @ android.app.activitythread.main(activitythread.java:4424) @ java.lang.reflect.method.invokenative(native method) @ java.lang.reflect.method.invoke(method.java:511) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:784) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:551) lists.xml
<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.v7.widget.cardview android:layout_width="300dp" android:layout_height="80dp" android:id="@+id/card"> <textview android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/texts" android:text="id" android:padding="20dp" android:layout_margin="20sp" android:textsize="20sp"/> <textview android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/textsa" android:layout_margin="20sp" android:text="resturants" android:textsize="20sp"/> </android.support.v7.widget.cardview>
the problem don't have initialized array when trying count. try changing to.
@override public int getitemcount() { return yours == null ? 0 : yours.size(); }
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