java - How to display the data from mySQL in listview in android? -

i can insert data database face problem cannot retrieve data database , display in listview in android. here coding part retrieve data. hope can solve this, thank you.

package com.example.iuum;   private progressdialog pdialog;   private static final string read_comments_url = "http://10.19.229.212/webservice/comments.php";   private static final string tag_success = "success"; private static final string tag_title = "title"; private static final string tag_posts = "posts"; private static final string tag_post_id = "post_id"; private static final string tag_username = "username"; private static final string tag_message = "message";  private jsonarray mcomments = null;  private arraylist<hashmap<string, string>> mcommentlist;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);      setcontentview(r.layout.activity_forum1a); }  @override protected void onresume() {      super.onresume();      new loadcomments().execute(); }  public void clickbtnwrite(view v) {     intent = new intent(forum1a.this, addforum.class);     startactivity(i); }  /**  * retrieves recent post data server.  */ public void updatejsondata() {       mcommentlist = new arraylist<hashmap<string, string>>();       jsonparser jparser = new jsonparser();      jsonobject json = jparser.getjsonfromurl(read_comments_url);       try {           mcomments = json.getjsonarray(tag_posts);           (int = 0; < mcomments.length(); i++) {             jsonobject c = mcomments.getjsonobject(i);              // gets content of each tag             string title = c.getstring(tag_title);             string content = c.getstring(tag_message);             string username = c.getstring(tag_username);               hashmap<string, string> map = new hashmap<string, string>();              map.put(tag_title, title);             map.put(tag_message, content);             map.put(tag_username, username);               mcommentlist.add(map);           }      } catch (jsonexception e) {         e.printstacktrace();     } }  /**  * inserts parsed data listview.  */ private void updatelist() {      listadapter adapter = new simpleadapter(this, mcommentlist,             r.layout.singelpost, new string[] { tag_title, tag_message,                     tag_username }, new int[] { r.id.title, r.id.message,                     r.id.username });       setlistadapter(adapter);       listview lv = getlistview();         lv.setonitemclicklistener(new onitemclicklistener() {          @override         public void onitemclick(adapterview<?> parent, view view,                 int position, long id) {            }     }); }    public class loadcomments extends asynctask<void, void, boolean> {      @override     protected void onpreexecute() {         super.onpreexecute();         pdialog = new progressdialog(forum1a.this);         pdialog.setmessage("loading comments...");         pdialog.setindeterminate(false);         pdialog.setcancelable(true);         pdialog.show();     }      @override     protected boolean doinbackground(void... arg0) {         updatejsondata();         return null;      }      @override     protected void onpostexecute(boolean result) {         super.onpostexecute(result);         pdialog.dismiss();         updatelist();     } } } 

add listview in activity_forum1a.xml

<listview     android:id="@+id/list_view"     android:layout_width="match_parent"     android:layout_height="wrap_content"></listview> 

take listview reference

    private listview mlist; 

initialize in oncreate

    mlist = (listview) findviewbyid(r.id.list_view); 

take listadapter class refernce

private listadapter listadapter; 

add setlistadapter method

public void setlistadapter(listadapter listadapter) {     this.listadapter = listadapter;     mlist.setadapter(listadapter); } 

change updatelist method to

    /**      * inserts parsed data listview.      */     private void updatelist() {          listadapter adapter = new simpleadapter(this, mcommentlist,                 r.layout.test, new string[] { tag_title, tag_message,                 tag_username }, new int[] { r.id.title, r.id.message,                 r.id.username });          setlistadapter(adapter); } 

and perform item click operation outside method, implementing onitemclicklistener