¿Cómo actualizar Listview después de eliminar un elemento en el evento Button Click en Android?
Quiero eliminar un elemento de la Vista de lista y, a la vez, Actualizar Vista de lista después de eliminar un elemento. ¿Cómo posible?
Estoy usando get all item usando JSON Parsing de la base de datos y elimino un elemento seleccionado al hacer clic en el botón. eliminar con éxito de la base de datos pero Listview no se actualiza a la vez. ¿cómo hacer?
Estoy usando Json Parsing. Base de datos no local.
En este caso, ¿cómo actualizar Listview al eliminar un elemento? por favor guíame. Gracias por adelantado.
Mi código es, archivo Detail.java
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);
}
}
}
}
Y la clase de adaptador es, archivo Adapter1.java
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);
};
}
}
El archivo detail.xml es,
<?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>
El archivo list_item.xml es,
<?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>