Starting a new Activity OnClick (Android) -

I'm trying to start an activity when I click on a button, but it does not seem to work can. When the button is pressed the app becomes free.

I am using this:

By the button:

  & amp; Button Android: ID Android: layout_height = "wrap_content" Android: onClick = "ExecJson" Android: text = "button" />   
 In the current activity:  
  Public Zero ExecJson (see view) {intent = intent (new, intent, listviewer.class); StartActivity; }   
 and the activity that I want to start:  
  package com.pxr.tutorial.json; Import java.net.MalformedURLException; Import java.net.URL; Import java.util.ArrayList; Import java.util.HashMap; Import org.json.JSONArray; Import org.json.JSONException; Import org.json.JSONObject; Import android.app.ListActivity; Importroid.os.Bundle; Import android.util.log; Import android.view.View; Import android.widget.AdapterView; Import android.widget.AdapterView.OnItemClickListener; Import android.widget.ListAdapter; Import android.widget.ListView; Android Import; Simple adapter; Import android.widget.Toast; Import com.pxr.tutorial.xmltest.R; @SuppressWarnings ("unused") public category list viewer activity has been created for the first time, while ListActivity is called {/ **. * / @Override Public Zero onCreate (bundled savedInstanceState) {super.onCreate (savedInstanceState); SetContentView (R.layout.listplaceholder); Array list & lieutenant; Hashmap & lt; String, string & gt; & Gt; Mylist = new Arrivals & Lt; Hashmap & lt; String, string & gt; & Gt; (); JSONObject json = JSONfunctions.getJSONfromURL ("http://oranjelan.nl/deelnemers.txt"); Try {JSONArray deelnemers = json.getJSONArray ("deelnemers"); For (int i = 0; i  String, string & gt; Map = new hashmap & lt; String, string & gt; (); JSONObject e = deelnemers.getJSONObject (i); Map.put ("id", String.valueOf (i)); Map.put ("name", "alias:" + e.getstring ("alias")); Map.put ("City", "Willplatz:" + E.Stustring ("Woodplots")); Map.put ("Gender", "GSLuct:" + E.Stustring ("GSLuct")); Mylist.add (map); }} Hold (JasonXEpisode E) {log (e. "Log_tag", "error parsing data" + e.trustin ()); } ListAdapter Adapter = New SimpleAdapter (It, MyList, R.layout.main, New String [] {"name", "city", "sex"}, new integer [] {R.id.item_title, R.id. Item_subtitle2, R.id.item_subtitle}); SetListAdapter (adapter); Last list view LV = getListView (); Lv.setTextFilterEnabled (true); Lv.setOnItemClickListener (New OnItemClickListener) {Public Zero onItemClick (AdapterView & LT;? & Gt; Parents, View View, Integer Status, Long ID) {@SuppressWarnings ("Uncontrolled") HashMap & String; String & Gt; o = (HashMap & lt; string, string & gt;) lv.getItemAtPosition (status); Toast.makeText (Listviewer.this, "id" '+ o.get ("id") +' ' Was gone. ", Toast.LENGTH_SHORT) .show ();}}); }}   
 Can anyone tell me what I am doing?   
 
 
 You can get web request (network related operation) on the menuui thread of your Activity list viewer Trying to  
 From this line,  
  JSONObject json = JSONfunctions.getJSONfromURL ("http://oranjelan.nl/deelnemers.txt");   
 Use this web request and try again.