android - My list is loading again when I am Pressing Back Button -
i getting arraylistindexoutofbound when pressing list item when orientation changed.as far knowledge of android have written parcelable code correctly.but think issues recycler view setup.i confused 2 declaration of adapter.help me
mainactivity.class
package com.reader.ashishyadav271.hackernewsmaterial; import android.content.context; import android.content.intent; import android.database.cursor; import android.database.sqlite.sqlitedatabase; import android.database.sqlite.sqlitestatement; import android.net.connectivitymanager; import android.net.networkinfo; import android.os.asynctask; import android.os.bundle; import android.os.parcelable; import android.os.persistablebundle; import android.support.v4.util.lrucache; import android.support.v7.app.appcompatactivity; import android.support.v7.widget.linearlayoutmanager; import android.support.v7.widget.recyclerview; import android.support.v7.widget.toolbar; import android.util.log; import android.view.menu; import android.view.menuitem; import android.view.view; import android.widget.listview; import android.widget.toast; import com.wang.avi.avloadingindicatorview; import org.json.jsonarray; import org.json.jsonobject; import java.io.inputstream; import java.io.inputstreamreader; import java.net.httpurlconnection; import java.net.url; import java.text.simpledateformat; import java.util.arraylist; import java.util.date; import java.util.hashmap; import java.util.list; import java.util.map; public class mainactivity extends appcompatactivity implements mycustomadapter.clicklistener { private static final string state_list = "state_list"; map<integer, string> articleurls = new hashmap<>(); map<integer, string> articletitles = new hashmap<>(); map<integer, string> articledates =new hashmap<>(); map<integer, string> articleauthors =new hashmap<>(); arraylist<integer> articleids=new arraylist<>(); sqlitedatabase articlesdb; arraylist<information> data=new arraylist<>(); arraylist<string> titles=new arraylist<>(); arraylist<string> urls=new arraylist<>(); arraylist<string> authors=new arraylist<>(); arraylist<string> dateandtimes=new arraylist<>(); mycustomadapter adapter; recyclerview recyclerview; avloadingindicatorview av; list<downloadtask> tasks; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); av= (avloadingindicatorview) findviewbyid(r.id.avloadingindicatorview); av.setvisibility(view.invisible); tasks = new arraylist<>(); toolbar toolbar = (toolbar) findviewbyid(r.id.toolbar); setsupportactionbar(toolbar); recyclerview= (recyclerview) findviewbyid(r.id.recyclerview); recyclerview.setlayoutmanager(new linearlayoutmanager(getapplicationcontext())); recyclerview.additemdecoration(new simpledivideritemdecoration( getapplicationcontext() )); articlesdb = this.openorcreatedatabase("articles", mode_private, null); articlesdb.execsql("create table if not exists article (id integer primary key," + " articleid integer," + " url varchar," + " title varchar," + " author varchar," + " date varchar)"); if(savedinstancestate != null) { data=savedinstancestate.getparcelablearraylist(state_list); adapter=new mycustomadapter(getapplicationcontext(),data); adapter.setclicklistener(this); recyclerview.setadapter(adapter); }else{ if (isonline()) { requestdata("https://hacker-news.firebaseio.com/v0/topstories.json?print=pretty"); } else { updatedisplay(); toast.maketext(this, "network isn't available", toast.length_long).show(); } } //adapter=new mycustomadapter(getapplicationcontext(),getdata()); //adapter.setclicklistener(this); //recyclerview.setadapter(adapter); } protected boolean isonline() { connectivitymanager cm = (connectivitymanager) getsystemservice(context.connectivity_service); networkinfo netinfo = cm.getactivenetworkinfo(); if (netinfo != null && netinfo.isconnectedorconnecting()) { return true; } else { return false; } } private void requestdata(string uri) { downloadtask task = new downloadtask(); task.execute(uri); } @override public void itemclicked(view view, int position) { intent = new intent(getapplicationcontext(), main2activity.class); i.putextra("articleurl", urls.get(position)); startactivity(i); } protected void updatedisplay() { adapter=new mycustomadapter(getapplicationcontext(),getdata()); adapter.setclicklistener(this); recyclerview.setadapter(adapter);; } @override protected void onsaveinstancestate(bundle outstate) { super.onsaveinstancestate(outstate); outstate.putparcelablearraylist(state_list, data); } public class downloadtask extends asynctask<string, void, string> { @override protected void onpreexecute() { super.onpreexecute(); if (tasks.size() == 0) { av.setvisibility(view.visible); } tasks.add(this); } @override protected string doinbackground(string... urls) { string result = ""; url url; httpurlconnection urlconnection; try { url = new url(urls[0]); urlconnection = (httpurlconnection) url.openconnection(); inputstream in = urlconnection.getinputstream(); inputstreamreader reader = new inputstreamreader(in); int data = reader.read(); while (data != -1) { char current = (char) data; result += current; data = reader.read(); } jsonarray jsonarray = new jsonarray(result); articlesdb.execsql("delete article"); (int = 0; < 15; i++) { string articleid = jsonarray.getstring(i); url = new url("https://hacker-news.firebaseio.com/v0/item/" + articleid + ".json?print=pretty"); urlconnection = (httpurlconnection) url.openconnection(); in = urlconnection.getinputstream(); reader = new inputstreamreader(in); data = reader.read(); string articleinfo = ""; while (data != -1 ) { char current = (char) data; articleinfo += current; data = reader.read(); } jsonobject jsonobject = new jsonobject(articleinfo); string articletitle = jsonobject.getstring("title"); string articleurl = jsonobject.getstring("url"); string articledate=jsonobject.getstring("time"); string articleauthor=jsonobject.getstring("by"); long unixseconds = long.valueof(articledate); date date = new date(unixseconds*1000l); // *1000 convert seconds milliseconds simpledateformat sdf = new simpledateformat("dd/mm/yyyy hh:mm:ss"); // format of date string formattedarticledate = sdf.format(date); articleids.add(integer.valueof(articleid)); articletitles.put(integer.valueof(articleid), articletitle); articleurls.put(integer.valueof(articleid), articleurl); articledates.put(integer.valueof(articleid), formattedarticledate); articleauthors.put(integer.valueof(articleid), articleauthor); string sql = "insert article (articleid, url, title, author, date) values (? , ? , ? , ?, ?)"; sqlitestatement statement = articlesdb.compilestatement(sql); statement.bindstring(1, articleid); statement.bindstring(2, articleurl); statement.bindstring(3, articletitle); statement.bindstring(4, articleauthor); statement.bindstring(5, formattedarticledate); statement.execute(); } }catch (exception e) { e.printstacktrace(); } return result; } @override protected void onpostexecute(string s) { super.onpostexecute(s); tasks.remove(this); if (tasks.size() == 0) { av.setvisibility(view.invisible); } updatedisplay(); } } private list<information> getdata() { /*list<information> data=new arraylist<>(); for(int i=0;i<20;i++){ titles.add(i,"wikileaks asssange wins un ruling on arbitrary detention"); url.add(i,"https://www.google.co.in/search?q=best+custom+list+row"); date.add(i,"3 hrs"); author.add(i,"aburan28"); } for(int i=0;i<20;i++){ information current=new information(); current.title=titles.get(i); current.url=url.get(i); current.author=author.get(i); current.date=date.get(i); data.add(current); } return data;*/ cursor c = articlesdb.rawquery("select * article", null); try { int urlindex = c.getcolumnindex("url"); int titleindex = c.getcolumnindex("title"); int authorindex = c.getcolumnindex("author"); int dateindex = c.getcolumnindex("date"); c.movetofirst(); titles.clear(); //urls.clear(); authors.clear(); dateandtimes.clear(); int i=0; while (c != null) { titles.add(c.getstring(titleindex)); urls.add(c.getstring(urlindex)); authors.add(c.getstring(authorindex)); dateandtimes.add(c.getstring(dateindex)); information current=new information(); current.title=titles.get(i); current.url=urls.get(i); current.author=authors.get(i); current.date = dateandtimes.get(i); data.add(current); i++; c.movetonext(); } }catch (exception e) { e.printstacktrace(); }finally { c.close(); } return data; } @override public boolean oncreateoptionsmenu(menu menu) { // inflate menu; adds items action bar if present. getmenuinflater().inflate(r.menu.menu_main, menu); return true; } @override public boolean onoptionsitemselected(menuitem item) { // handle action bar item clicks here. action bar // automatically handle clicks on home/up button, long // specify parent activity in androidmanifest.xml. int id = item.getitemid(); //noinspection simplifiableifstatement if (id == r.id.action_settings) { startactivity(new intent(getapplicationcontext(),settingsactivity.class)); return true; } if (id == r.id.action_about) { startactivity(new intent(getapplicationcontext(),about.class)); return true; } return super.onoptionsitemselected(item); } } information.class
package com.reader.ashishyadav271.hackernewsmaterial; import android.os.parcel; import android.os.parcelable; public class information implements parcelable { public string title; public string author; public string date; public string url; public information(){ } protected information(parcel in) { title = in.readstring(); author = in.readstring(); date = in.readstring(); url = in.readstring(); } public static final creator<information> creator = new creator<information>() { @override public information createfromparcel(parcel in) { return new information(in); } @override public information[] newarray(int size) { return new information[size]; } }; @override public int describecontents() { return 0; } @override public void writetoparcel(parcel dest, int flags) { dest.writestring(title); dest.writestring(author); dest.writestring(date); dest.writestring(url); } } log cat error
02-06 14:52:58.106 8369-8369/com.reader.ashishyadav271.hackernewsmaterial e/androidruntime: fatal exception: main process: com.reader.ashishyadav271.hackernewsmaterial, pid: 8369 java.lang.indexoutofboundsexception: invalid index 0, size 0 @ java.util.arraylist.throwindexoutofboundsexception(arraylist.java:255) @ java.util.arraylist.get(arraylist.java:308) @ com.reader.ashishyadav271.hackernewsmaterial.mainactivity.itemclicked(mainactivity.java:137) @ com.reader.ashishyadav271.hackernewsmaterial.mycustomadapter$myviewholder.onclick(mycustomadapter.java:77) @ android.view.view.performclick(view.java:4471) @ android.view.view$performclick.run(view.java:18778) @ android.os.handler.handlecallback(handler.java:808) @ android.os.handler.dispatchmessage(handler.java:103) @ android.os.looper.loop(looper.java:193) @ android.app.activitythread.main(activitythread.java:5345) @ java.lang.reflect.method.invokenative(native method) @ java.lang.reflect.method.invoke(method.java:515) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:828) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:644) @ dalvik.system.nativestart.main(native method)
now after years.i have used. flag_activity_clear_top - if set, , activity being launched running in current task, instead of launching new instance of activity, of other activities on top of closed , intent delivered (now on top) old activity new intent.
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