java - Cannot list the data in my android application from Mysql -
new in android development. trying database crud operation in android application. can insert data mysql.am using php , json parsing it.when data inserted database, next activity should listing data.the problem no data coming listing activity. activity coming without data. kindly me . java code listing products public class allproductsactivity extends listactivity { // progress dialog private progressdialog pdialog; // creating json parser object jsonparser jparser = new jsonparser(); arraylist<hashmap<string, string>> productslist; // url products list private static string url_all_products = "http://10.0.2.2/get_all_products.php"; // json node names private static final string tag_success = "success"; private static final string tag_products = "products"; private static final string tag_pid = "pid"; private static final string tag_name = "name"; // products jsonarray jsonarray products = null; @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.all_products); // hashmap listview productslist = new arraylist<hashmap<string, string>>(); // loading products in background thread new loadallproducts().execute(); // listview listview lv = getlistview(); // on seleting single product // launching edit product screen lv.setonitemclicklistener(new onitemclicklistener() { @override public void onitemclick(adapterview<?> parent, view view, int position, long id) { // getting values selected listitem string pid = ((textview) view.findviewbyid(r.id.pid)).gettext() .tostring(); // starting new intent intent in = new intent(getapplicationcontext(), editproductactivity.class); // sending pid next activity in.putextra(tag_pid, pid); // starting new activity , expecting response startactivityforresult(in, 100); } }); } // response edit product activity @override protected void onactivityresult(int requestcode, int resultcode, intent data) { super.onactivityresult(requestcode, resultcode, data); // if result code 100 if (resultcode == 100) { // if result code 100 received // means user edited/deleted product // reload screen again intent intent = getintent(); finish(); startactivity(intent); } } /** * background async task load product making http request * */ class loadallproducts extends asynctask<string, string, string> { /** * before starting background thread show progress dialog * */ @override protected void onpreexecute() { super.onpreexecute(); pdialog = new progressdialog(allproductsactivity.this); pdialog.setmessage("loading products. please wait..."); pdialog.setindeterminate(false); pdialog.setcancelable(false); pdialog.show(); } /** * getting products url * */ protected string doinbackground(string... args) { // building parameters list<namevaluepair> params = new arraylist<namevaluepair>(); // getting json string url jsonobject json = jparser.makehttprequest(url_all_products, "get", params); // check log cat json reponse log.d("all products: ", json.tostring()); try { // checking success tag int success = json.getint(tag_success); if (success == 1) { // products found // getting array of products products = json.getjsonarray(tag_products); // looping through products (int = 0; < products.length(); i++) { jsonobject c = products.getjsonobject(i); // storing each json item in variable string id = c.getstring(tag_pid); string name = c.getstring(tag_name); // creating new hashmap hashmap<string, string> map = new hashmap<string, string>(); // adding each child node hashmap key => value map.put(tag_pid, id); map.put(tag_name, name); // adding hashlist arraylist productslist.add(map); } } else { // no products found // launch add new product activity intent = new intent(getapplicationcontext(), newproductactivity.class); // closing previous activities i.addflags(intent.flag_activity_clear_top); startactivity(i); } } catch (jsonexception e) { e.printstacktrace(); } return null; } /** * after completing background task dismiss progress dialog * **/ protected void onpostexecute(string file_url) { // dismiss dialog after getting products pdialog.dismiss(); // updating ui background thread runonuithread(new runnable() { public void run() { /** * updating parsed json data listview * */ listadapter adapter = new simpleadapter( allproductsactivity.this, productslist, r.layout.list_item, new string[] { tag_pid, tag_name}, new int[] { r.id.pid, r.id.name }); // updating listview setlistadapter(adapter); } }); } } } here in code , trying display 3 data , "name, price, description. php file retrieve data database mysql , , convert strings json objects. javacode call json class , list data. can insert data mysql.am using php , json parsing it.when data inserted database, next activity should listing data.the problem no data coming listing activity. activity coming without data. kindly me . json class parsing or converting follows json parsing code .in code first created function json url . code making http request , post method using if , else statement . in else method put code method . converted json object , , above android code call , display in activity.. used json parser class json url. class supports 2 http request methods , post json url. getting json making http call, adding async method make http calls on background thread. add follwing method in main activity class public jsonparser() { } // function json url // making http post or mehtod public jsonobject makehttprequest(string url, string method, list<namevaluepair> params) { // making http request try { // check request method if(method == "post"){ // request method post // defaulthttpclient defaulthttpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(url); httppost.setentity(new urlencodedformentity(params)); httpresponse httpresponse = httpclient.execute(httppost); httpentity httpentity = httpresponse.getentity(); = httpentity.getcontent(); }else if(method == "get"){ // request method defaulthttpclient httpclient = new defaulthttpclient(); string paramstring = urlencodedutils.format(params, "utf-8"); url += "?" + paramstring; httpget httpget = new httpget(url); httpresponse httpresponse = httpclient.execute(httpget); httpentity httpentity = httpresponse.getentity(); = httpentity.getcontent(); } } catch (unsupportedencodingexception e) { e.printstacktrace(); } catch (clientprotocolexception e) { e.printstacktrace(); } catch (ioexception e) { e.printstacktrace(); } try { bufferedreader reader = new bufferedreader(new inputstreamreader( is, "iso-8859-1"), 8); stringbuilder sb = new stringbuilder(); string line = null; while ((line = reader.readline()) != null) { sb.append(line + "\n"); } is.close(); json = sb.tostring(); } catch (exception e) { log.e("buffer error", "error converting result " + e.tostring()); } // try parse string json object try { jobj = new jsonobject(json); } catch (jsonexception e) { log.e("json parser", "error parsing data " + e.tostring()); } // return json string return jobj; } } json parsing code .in code first created function json url . code making http request , post method using if , else statement . in else method put code method . converted json object , , above android code call , display in activity.. used json parser class json url. class supports 2 http request methods , post json url. getting json making http call, adding async method make http calls on background thread. add follwing method in main activity class thankyou
@ manish dubay
according instruction got changed code in jsonobject.still nothing displayed on allproducts activity. myt logcat error when add log.v("json string","result => "+json);
03-10 03:49:54.491: w/system.err(1559): org.json.jsonexception: no value products 03-10 03:49:54.491: w/system.err(1559): @ org.json.jsonobject.get(jsonobject.java:354) 03-10 03:49:54.508: i/choreographer(1559): skipped 97 frames! application may doing work on main thread. 03-10 03:49:54.528: w/system.err(1559): @ org.json.jsonobject.getjsonarray(jsonobject.java:548) 03-10 03:49:54.558: w/system.err(1559): @ com.example.sampleapp2.allproductsactivity$loadallproducts.doinbackground(allproductsactivity.java:141) 03-10 03:49:54.618: w/system.err(1559): @ com.example.sampleapp2.allproductsactivity$loadallproducts.doinbackground(allproductsactivity.java:1) 03-10 03:49:54.668: w/system.err(1559): @ android.os.asynctask$2.call(asynctask.java:287) 03-10 03:49:54.698: w/system.err(1559): @ java.util.concurrent.futuretask.run(futuretask.java:234) 03-10 03:49:54.718: w/system.err(1559): @ android.os.asynctask$serialexecutor$1.run(asynctask.java:230) 03-10 03:49:54.748: w/system.err(1559): @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1080) 03-10 03:49:54.788: w/system.err(1559): @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:573) 03-10 03:49:54.898: i/choreographer(1559): skipped 84 frames! application may doing work on main thread. 03-10 03:49:54.958: w/system.err(1559): @ java.lang.thread.run(thread.java:841) 03-10 03:49:55.038: i/choreographer(1559): skipped 83 frames! application may doing work on main thread. 03-10 03:49:55.168: i/choreographer(1559): skipped 212 frames! application may doing work on main thread. 03-10 03:49:55.218: i/choreographer(1559): skipped 55 frames! application may doing work on main thread.
error parsing data org.json.jsonexception: value get_all_products.php of type java.lang.string cannot converted jsonobject states don't have valid json string in resopnse coming web service. becuase of jobj = isvalidjson(json); doesn't return json object.
in above code, at
json = sb.tostring(); you creating string named json , assign string builder object value it. logcat says not geeting valid json string @ below line,
try { jobj = new jsonobject(json); } catch (jsonexception e) { log.e("json parser", "error parsing data " + e.tostring()); } so throws error parsing json string. in case have check whether go t valid json string server in response. make changes in above code:
public boolean isvalidjson(string test) { try { new jsonobject(test); return true; } catch(jsonexception ex) { return false; } } and, in code:
try { if(isvalidjson(json) { jobj = new jsonobject(json); } catch (jsonexception e) { log.e("json parser", "error parsing data " + e.tostring()); } }
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