java - ANDROID - Populate custom ListView with Database on Fragment -
i have custom listview , database, i'm trying populate listview database, not work.
my code:
public class mainactivity extends listfragment { public sql mydbhelper; public sqlitedatabase db = null; public list<string> mostrar, mostrar2; adaptadortitulares adapter; public listview list; @override public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) { // if extending activity view root = inflater.inflate(r.layout.activity_main, container, false); try { mydbhelper = new sql(getactivity()); mydbhelper.createdatabase(getactivity()); } catch (exception e) { } new threadbd().execute(); list = (listview) root.findviewbyid(android.r.id.list); list.setonitemclicklistener(new onitemclicklistener() { @override public void onitemclick(adapterview<?> arg0, view arg1, int posicion, long arg3) { string bebida=mostrar.get(posicion); string precio=mostrar2.get(posicion); //toast.maketext(getapplicationcontext(), "el precio es: " + precio + "y la bebida es: " + bebida, toast.length_long).show(); } }); return root; }// end oncreate class adaptadortitulares extends baseadapter { private activity mactivityact; private layoutinflater minflater; private arraylist<titular> mlitems; public adaptadortitulares(activity a, arraylist<titular> it) { try { mactivityact = a; mlitems = it; minflater = (layoutinflater) mactivityact .getsystemservice(context.layout_inflater_service); } catch (exception e) { } } public class vistah { public textview nombree; public textview grupoo; } @override public int getcount() { return mlitems.size(); } @override public object getitem(int position) { return position; } @override public long getitemid(int position) { return position; } @override public view getview(int position, view convertview, viewgroup parent) { view vi = convertview; vistah vh = null; if (vi == null) { vi = minflater.inflate(r.layout.target_item, null); vh = new vistah(); vh.nombree = (textview) vi.findviewbyid(r.id.item_title); vh.grupoo = (textview) vi.findviewbyid(r.id.item_counter); vi.settag(vh); } vh = (vistah) vi.gettag(); titular notice = mlitems.get(position); vh.nombree.settext(notice.getdate()); vh.grupoo.settext(notice.gettitle()); return vi; } @override public void unregisterdatasetobserver(datasetobserver observer) { if (observer != null) { super.unregisterdatasetobserver(observer); } } } private class threadbd extends asynctask<void, void, void> { @override protected void doinbackground(void... params) { mydbhelper.opendatabase(); db = mydbhelper.getreadabledatabase(); cursor c = db.rawquery("select id lista order id desc", null); c.movetofirst(); int num = c.getint(0); mostrar = new arraylist<string>(num); mostrar2 = new arraylist<string>(num); (int = 0; <= num; i++) { cursor d = db.rawquery( "select nombre, precio lista id=" + + "", null); if (d.movetofirst()) { mostrar.add(d.getstring(0)); mostrar2.add(string.valueof(d.getdouble(1))); } }// fin return null; }// end inbackground protected void onpostexecute(void result) { titular titular; arraylist<titular> mlist = new arraylist<titular>(); (int = 0; < mostrar.size(); i++) { try { titular = new titular(mostrar.get(i), mostrar2.get(i)); mlist.add(titular); } catch (exception e) { } adaptadortitulares actualizaadapter=new adaptadortitulares(getactivity(), mlist); list.setadapter(actualizaadapter); } } } } titular.java
public class titular { private string date; private string title; public titular(string date, string title) { // recibe el nombre de la canción, grupo y su tiempo this.date = date; this.title = title; } public string getdate() { return date; } public void setdate(string date) { this.date = date; } public string gettitle() { return title; } public void settitle(string title) { this.title = title; } } sql.java
public class sql extends sqliteopenhelper { private static string db_path = "/data/data/com.example.listprueba/databases/"; private static string db_name = "prueba"; private final context mycontext; private sqlitedatabase mydatabase; public sql(context context) { super(context, db_name, null, 1); this.mycontext = context; } public void createdatabase(context contexto) throws ioexception { boolean dbexist = checkdatabase(); if (dbexist) { } else { this.getreadabledatabase(); try { copydatabase(); } catch (ioexception e) { throw new error("error copiado base de datos"); } } } private boolean checkdatabase() { sqlitedatabase checkdb = null; try { string mypath = db_path + db_name; checkdb = sqlitedatabase.opendatabase(mypath, null, sqlitedatabase.open_readonly); } catch (sqliteexception e) { } if (checkdb != null) { checkdb.close(); } return checkdb != null ? true : false; } private void copydatabase() throws ioexception { inputstream myinput = mycontext.getassets().open(db_name); string outfilename = db_path + db_name; outputstream myoutput = new fileoutputstream(outfilename); byte[] buffer = new byte[1024]; int length; while ((length = myinput.read(buffer)) > 0) { myoutput.write(buffer, 0, length); } // liberamos los streams myoutput.flush(); myoutput.close(); myinput.close(); } public void opendatabase() throws sqlexception { string mypath = db_path + db_name; mydatabase = sqlitedatabase.opendatabase(mypath, null, sqlitedatabase.open_readonly); } public synchronized void close() { if (mydatabase != null) mydatabase.close(); super.close(); } @override public void oncreate(sqlitedatabase db) { } @override public void onupgrade(sqlitedatabase db, int oldversion, int newversion) { } } activity_mail.xml
<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <listview android:id="@android:id/list" android:layout_width="wrap_content" android:layout_height="match_parent" > </listview> </linearlayout> target_item.xml
<?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="48dp" android:background="#f3f3f3"> <!-- icon --> <imageview android:id="@+id/item_icon" android:layout_width="32dp" android:layout_height="32dp" android:layout_alignparentleft="true" android:layout_marginleft="8dp" android:layout_marginright="8dp" android:layout_margintop="8dp" android:src="@drawable/ic_action_help" /> <!-- title --> <textview android:id="@+id/item_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_torightof="@+id/item_icon" android:layout_alignbaseline="@+id/item_counter" android:textsize="18dp" /> <!-- counter --> <textview android:id="@+id/item_counter" android:layout_width="50dp" android:layout_height="32dp" android:layout_alignparentright="true" android:layout_marginright="8dp" android:layout_margintop="8dp" android:background="@drawable/rectangle" android:gravity="center" android:textcolor="#ffffff" android:textsize="12sp" android:textstyle="bold" /> </relativelayout> error
06-08 22:35:31.091: e/androidruntime(1470): fatal exception: main 06-08 22:35:31.091: e/androidruntime(1470): process: com.example.listprueba, pid: 1470 06-08 22:35:31.091: e/androidruntime(1470): java.lang.runtimeexception: unable instantiate activity componentinfo{com.example.listprueba/com.example.listprueba.mainactivity}: java.lang.classcastexception: com.example.listprueba.mainactivity cannot cast android.app.activity 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.activitythread.performlaunchactivity(activitythread.java:2121) 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.activitythread.handlelaunchactivity(activitythread.java:2245) 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.activitythread.access$800(activitythread.java:135) 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.activitythread$h.handlemessage(activitythread.java:1196) 06-08 22:35:31.091: e/androidruntime(1470): @ android.os.handler.dispatchmessage(handler.java:102) 06-08 22:35:31.091: e/androidruntime(1470): @ android.os.looper.loop(looper.java:136) 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.activitythread.main(activitythread.java:5017) 06-08 22:35:31.091: e/androidruntime(1470): @ java.lang.reflect.method.invokenative(native method) 06-08 22:35:31.091: e/androidruntime(1470): @ java.lang.reflect.method.invoke(method.java:515) 06-08 22:35:31.091: e/androidruntime(1470): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:779) 06-08 22:35:31.091: e/androidruntime(1470): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:595) 06-08 22:35:31.091: e/androidruntime(1470): @ dalvik.system.nativestart.main(native method) 06-08 22:35:31.091: e/androidruntime(1470): caused by: java.lang.classcastexception: com.example.listprueba.mainactivity cannot cast android.app.activity 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.instrumentation.newactivity(instrumentation.java:1061) 06-08 22:35:31.091: e/androidruntime(1470): @ android.app.activitythread.performlaunchactivity(activitythread.java:2112) 06-08 22:35:31.091: e/androidruntime(1470): ... 11 more do know can error? should change anything?, if extend listactivity class works perfectly.
i dont know how can extends fragments instead listactivity....
try having mainactivity extend fragmentactivity , create new class listfragment can extend fragment. here can populate listview data db. check nice tutorial here >> http://www.vogella.com/tutorials/androidlistview/article.html#listfragments
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