Reena Reena - 1 month ago 6
Android Question

how to Listview Refresh after Delete an item on Button Click event in android?

I want to delete an item from Listview, and at a time Refresh Listview after deleting an item. How to possible?

I am using get all item using JSON Parsing from database and delete an selected an item on click of button. delete successfully from database but Listview not refresh at a time. how to do?

I am using Json Parsing. not local database.

In This case, How to refresh Listview when Deleting Item?
please Guide me.
Thanks in Advance.

My Code is,
Detail.java File

public class Detail extends Activity {
ListView lstDetail = null;
/** String */
String urlGetDetailData = null;

/** Declare another variable for Listview */
Adapter1 adapter1 = null;
ArrayList<Detail> myList = new ArrayList<Detail>();
/** Hashmap for ListView */
ArrayList<HashMap<String, String>> dataList = null;

/** JSON Node names */
public static final String TAG_MEMBER_ID = "mem_id";
public static final String TAG_ID = "id";
public static final String TAG_USER_ID = "userid";
public static final String TAG_STATUS = "Status";

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
onCreateActivity(R.layout.detail);

initializeWidgets();
}

private void initializeWidgets() {
/** ListView */
lstDetail = (ListView) findViewById(R.id.lstDetail);

urlGetDetailData = "http://example.com/getdata.php?id="
+ strId;

new GetDetailData().execute();
myList.remove(position);
Adapter1.this.notifyDataSetChanged();

}

/**
* Async task class to get json by making HTTP call
* */
private class GetDetailData extends AsyncTask<Void, Void, Void> {
JSONObject jsonobject;
JSONArray jsonarray;

@Override
protected void onPreExecute() {
super.onPreExecute();
}

@Override
protected Void doInBackground(Void... arg0) {
dataList = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONFunctions.getJSONfromURL(urlGetDetailData);

try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("data");

for (int i = 0; i < jsonarray.length(); i++) {

HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects

map.put("mem_id", String.valueOf(jsonobject
.getString(TAG_MEMBER_ID)));
map.put("id",
jsonobject.getString(TAG_ID));

map.put("userid", jsonobject.getString(TAG_USER_ID));
map.put("Status", jsonobject.getString(TAG_STATUS));

dataList.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}

return null;
}

@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (dataList.size() != 0) {
lstDetail.setVisibility(View.VISIBLE);
Adapter1 = new Adapter1(Detail.this,
dataList);
lstDetail.setAdapter(Adapter1);
} else {
lstDetail.setVisibility(View.GONE);
}
}
}
}


And Adapter Class is,
Adapter1.java File

public class Adapter1 extends BaseAdapter {
public ArrayList<HashMap<String, String>> arrData = null;
Context context = null;
LayoutInflater layoutInflater = null;
HashMap<String, String> getDetailData = new HashMap<String, String>();

/** String */
String strMemberId = null, urlDelete = null;

/** Constructor */
public Adapter1(Context context,
ArrayList<HashMap<String, String>> arrData) {
layoutInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.context = context;
this.arrData = arrData;
}

@Override
public int getCount() {
return arrData.size();
}

@Override
public Object getItem(int position) {
return arrData.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder = null;
if (convertView == null) {
convertView = layoutInflater.inflate(
R.layout.list_item, null);

viewHolder = new ViewHolder();
getData = arrData.get(position);

/** Initialize Widgets */

viewHolder.imgCancel = (ImageView) convertView
.findViewById(R.id.imgCancel);

viewHolder.imgCancel
.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
strMemberId = arrData.get(
position).get(
Detail.TAG_MEMBER_ID);
urlDelete = "http://example.com/delete.php?mem_id="
+ strMemberId;
new DeleteComments().execute();
}
});

/** TextView */
viewHolder.txtMemberId = (TextView) convertView
.findViewById(R.id.txtMemberId);
viewHolder.txtId = (TextView) convertView
.findViewById(R.id.txtId);

viewHolder.txtDesc = (TextView) convertView
.findViewById(R.id.txtDesc);

/** Set Value */


viewHolder.txtMemberId.setText(getDetailData
.get(Detail.TAG_MEMBER_ID));
viewHolder.txtId.setText(getDetailData
.get(Detail.TAG_ID));

viewHolder.txtDesc.setText(getDetailData
.get(Detail.TAG_STATUS));

convertView.setTag(viewHolder);

} else {
viewHolder = (ViewHolder) convertView.getTag();
}
return convertView;
}

/** ViewHolder Class */
@SuppressLint("NewApi")
public static class ViewHolder {
ImageView imgCancel = null;
TextView txtMemberId = null, txtId = null,txtDesc = null;
}

public class DeleteComments extends AsyncTask<Void, Void, Void> {
protected void onPreExecute() {
super.onPreExecute();
}

@Override
protected Void doInBackground(Void... arg0) {
ServiceHandler sh = new ServiceHandler();
String jsonStr = sh.makeServiceCall(urlDelete,
ServiceHandler.GET);
Log.d("Response : delete join comments", ">" + jsonStr);

return null;
}

protected void onPostExecute(Void result) {
super.onPostExecute(result);

};
}
}


detail.xml File is,

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/re/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >

<ListView
android:id="@+id/lstDetail"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
</ListView>
</RelativeLayout>


list_item.xml file is,

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/re/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >

<LinearLayout
android:id="@+id/contentLayout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="vertical" >

<TextView
android:id="@+id/txtId"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="111" />

<TextView
android:id="@+id/txtDesc"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>

<ImageView
android:id="@+id/imgCancel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:src="@drawable/cancel" />

<TextView
android:id="@+id/txtMemberId"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/txtUserEventId"
android:layout_alignBottom="@+id/txtUserEventId"
android:layout_alignParentLeft="true"
android:text="222" />
</RelativeLayout>

Answer

in your custom adapter call this.notifyDataSetChanged(); where you are performing delete functionality and deleting that element from arrayList which is set to that adapter

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