Develop Reference

How to display checkbox on every entry in a listView

From this Activity i get text from textField and display it in a ListView.
Now i want to to add check box on every entry in a listView Cell and also like to know how to display more than one text in a single ListView Cell.
Help with code will be appreciated.
Here is my code ....
public class AfterRegister extends AppCompatActivity
{
ListView listView;
EditText editText;
Button insertItemButton;
ArrayList<String> arrayList = new ArrayList<String>();
ArrayAdapter<String> adapter;
CheckBox checkBox;
StoreRegistrationDataBase storeRegistrationDataBase;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_after_register);
storeRegistrationDataBase = new StoreRegistrationDataBase(this);
storeRegistrationDataBase = storeRegistrationDataBase.open();
checkBox = (CheckBox) findViewById(R.id.checkbox);
insertItemButton = (Button) findViewById(R.id.button4);
insertItemButton.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
editText = (EditText) findViewById(R.id.editText2);
listView = (ListView) findViewById(R.id.listView);
String getEditTextString = editText.getText().toString();
if(isAlphaNumeric(getEditTextString))
{
if(!getEditTextString.equals(""))
{
arrayList.add(getEditTextString);
adapter = new ArrayAdapter<String>(getBaseContext(), R.layout.text_view_layout, R.id.achView1, arrayList);
listView.setAdapter(adapter);
adapter.notifyDataSetChanged();
editText.setText("");
}
else
{
Toast.makeText(AfterRegister.this, "You can not insert empty field", Toast.LENGTH_SHORT).show();
}
}
else
{
Toast.makeText(AfterRegister.this, "Remove Space", Toast.LENGTH_SHORT).show();
}
}
});
listView.setOnTouchListener(new View.OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{
return false;
}
});
}
public boolean isAlphaNumeric(String s)
{
String pattern= "^[a-zA-Z0-9]*$";
if(s.matches(pattern))
{
return true;
}
return false;
}
}

You have to use a BaseAdapter and some Getter/Setter methods to add multiple texts/images/other UI elements in each item of your list view.
You have to implement multiple things to get this result. Here they are --
Create a Custom Layout for each item of your ListView.
listview_item_layout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/layout_textview1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15sp"
android:layout_marginRight="5dip"
android:textStyle="bold"/>
<TextView
android:id="#+id/layout_textview2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15sp"
android:layout_marginLeft="5dip"
android:textStyle="bold"/>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/checkbox"
android:text="Test"/>
</LinearLayout>
Create a custom class and add some Getter/Setter methods.
ListRowItem.java
public class ListRowItem implements Serializable{
String carrier,number;
public String getCarrier(){
return carrier;
}
public String getNumber(){
return number;
}
public void setCarrier(String ba_carrier){
carrier = ba_carrier;
}
public void setNumber(String ba_number){
number = ba_number;
}
}
Create a custom class and extend the BaseAdapter class.
public class MyBaseAdapter extends BaseAdapter {
public Context ba_context;
public ArrayList<ListRowItem> listitem = new ArrayList<>();
public LayoutInflater inflater;
ListRowItem currentlistitem;
public MyBaseAdapter(Context ma_context, ArrayList<ListRowItem> ma_listitem) {
super();
this.ba_context = ma_context;
this.listitem = ma_listitem;
inflater = (LayoutInflater) ba_context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public int getCount() {
return this.listitem.size();
}
#Override
public Object getItem(int position) {
return this.listitem.get(position);
}
#Override
public long getItemId(int position) {
return (long) position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView;
if (convertView == null)
vi = inflater.inflate(R.layout.listview_item_layout, parent, false);
TextView carrier = (TextView) vi.findViewById(R.id.layout_textview1);
TextView number = (TextView) vi.findViewById(R.id.layout_textview2);
currentlistitem = listitem.get(position);
String str_carrier = currentlistitem.getCarrier();
String str_number = currentlistitem.getNumber();
carrier.setText(str_carrier);
number.setText(str_number);
return vi;
}
}
Finally, populate your ArrayList and set the Adapter in your MainActivity.
ArrayList<ListRowItem> listitem = new ArrayList<>();
Context context = TestActivity.this;
MyBaseAdapter baseAdapter;
ListRowItem lr = new ListRowItem();
lr.setNumber(number);
lr.setCarrier(carrier);
listitem.add(lr);
baseAdapter = new MyBaseAdapter(context,listitem);
setContentView(R.layout.activity_test);
listView = (ListView) findViewById(R.id.list_view);
listView.setAdapter(baseAdapter);
Hope this helps!!

iterate through ListView and delete list items based on their content

I have a ListView setup which I dynamically add items to with each item having different data. One of the pieces of data is a time/date which is shown in a TextView in my custom List item layout. In the onResume() method of my Fragment I would like to remove items that have a date shown which is before the current date.
The List item layout is as follows:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/pi_rl"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/pi_tv_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30sp" />
<TextView
android:id="#+id/pi_tv_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/pi_tv_title"
android:textSize="24sp" />
</RelativeLayout>
The idea that I had to solve this was to create a loop, which iterated through all the items checking the content of the date TextView for each item. Then, if the date was before the current date, it would remove the item.
I am currently able to delete items based on there position, but I can't work out how to delete individual list items if they have a certain content.
This is what I have so far:
#Override
public void onResume() {
// TODO Auto-generated method stub
super.onResume();
int items = DataModel.getInstance().getPendingItemList().size(); // Number of items in the list
if (items > 0) {
for (int i = 1; i <= items; i++) { // This loops through all my items. Do I want to use position instead?
Log.i("for loop", "" + i);
// This doesn't work because it tries to get the content for all the items not just one.
TextView tv_date = (TextView) getView()
.findViewById(R.id.pi_tv_date);
CharSequence c = tv_date.getText(); // Causes force close
// Here I will have my if(date shown != current date){
//deleteItem
//}
}
}
}
EDIT: This is my adapter code:
private class PendingAdapter extends BaseAdapter { // This happens whenever
// onCreate is called.
private List<Map<String, Object>> mPendingItemList;
public PendingAdapter() {
mPendingItemList = DataModel.getInstance().getPendingItemList();
}
#Override
public int getCount() {
return mPendingItemList.size();
}
#Override
public Object getItem(int position) {
return mPendingItemList.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (null == convertView) {
convertView = LayoutInflater.from(getActivity()).inflate(
R.layout.pending_item, null);
// Log.i("convertView", "was null");
}
TextView tv_title = (TextView) convertView
.findViewById(R.id.pi_tv_title);
TextView tv_date = (TextView) convertView
.findViewById(R.id.pi_tv_date);
HashMap<String, String> itemDataHashMap = (HashMap<String, String>) getItem(position);
tv_title.setText(itemDataHashMap.get("planet"));
tv_date.setText(itemDataHashMap.get("date"));
return convertView;
}
}
EDIT 2:
As per Ali AlNoaimi's answer, I have added this inside my Adapter:
public void refreshMyAdapter() {
if(mPendingItemList.size() > 0) {
List<Map<String, Object>> newPendingList = mPendingItemList;
for (int i = 0; i < mPendingItemList.size(); i++) {
Map<String, Object> item = mPendingItemList.get(i);
TextView tv_title = (TextView) histView
.findViewById(R.id.pi_tv_title);
String s_title;
s_title = tv_title.getText().toString();
Log.i("s_title", s_title);
if(s_title == "foo") {
newPendingList.remove(item);
}
}
mPendingItemList = newPendingList;
}
}
and this to the onResume():
#Override
public void onResume() {
// TODO Auto-generated method stub
super.onResume();
final Handler handler = new Handler(); new Thread(new Runnable() {
#Override
public void run() {
while(true) {
handler.post(new Runnable() {
#Override
public void run() {
simpleAdpt.refreshMyAdapter();
simpleAdpt.notifyDataSetChanged();
}
});
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
This still does not work.
FINAL EDIT: Ali AlNoaimi's answer did work, I was just comparing strings incorrectly.
I hope this makes sense! Thank you

I'm not sure you understand how ListView works. A ListView is the visual representation of the data in your adapter, so you should never try to edit, add or delete views of a ListView directly, but instead edit the data and then call notifyDataSetChanged() on your adapter.
The ListView will then check for changes in your adapter's data and refresh the views accordingly.
For your specific problem, it means that you should work directly with mPendingItemList, find the items that have a specific content, remove them and then call notifyDataSetChanged().

Add this method to your adapter:
public void refreshMyAdapter() {
private List<Map<String, Object>> newPendingList;
for (int i = 0; i < mPendingItemList.size(); i++) {
Map<String, Object> item = mPendingItemList.get(i);
if(it matches) {
newPendingList.add(item);
}
}
mPendingItemList = newPendingList;
}
and in your main activity, fragment
final Handler handler = new Handler();
new Thread(new Runnable() {
#Override
public void run() {
while(true) {
handler.post(new Runnable() {
#Override
public void run() {
yourPendingAdapter.refreshMyAdapter();
yourPendingAdapter.notifyDataSetChanged();
}
});
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();

Bedst way is to remove the items in the ArrayList you used when creating the adapter then call notifyDataSetChanged(); on the adabter to update the listview.

to have a coherent implementation, keep data processing on the DataModel.
add to DataModel class this method:
public void clearObsoleteItems(){
//TODO: add you implementation to clear the obsolete items from the List of items holded by the singleton class.
}
add on your adapter class PendingAdapter a setter for items list:
public void setPendingItemList(List<Map<String, Object>> mPendingItemList) {
this.mPendingItemList = mPendingItemList;
notifyDataSetChanged();
}
from the activity onResume call:
DataModel.getInstance().clearObsoleteItems();
mAdapter.setPendingItemList(DataModel.getInstance().getPendingItemList());

Centering the clicked item in listview in Android

I have a list view in left of the screen and on click of the item i want to update a text on the right half of the screen, what i want to do here is that to move the clicked item in center of the listview. Like if the item is on top and i click on it it automatically moves to the center of the list view, how I can do this? Any kind of help will be appreciated.
I have a listview in which 7 items are visible and on startup 4th item will be selected as this is in center of the visible items in listview and if there are n items and whichever item is selected by user will be in center of the visible items in listview. Like i have 10 items and on start 4th is selected and when user selects the 3rd item, nth item from listview should come to index zero and and 3rd will come to position 4. Similarly for every other selected item? Can any one provide a code snippet for this?

Change items order in ListView source Array and then call notifyDataSetChanged() in ListView Adapter
EDIT: Code sample
public class ListAdapter extends BaseAdapter{
private Activity activity;
private ArrayList<ListRowObject> listItems;
public ListAdapter(Activity activity){
this.activity = activity;
listItems = new ArrayList<ListRowObject>();
}
public void addItem(ListRowObject item){
listItems.add(item);
notifyDataSetChanged();
}
public void addItems(ArrayList<ListRowObject> items){
listItems = items;
notifyDataSetChanged();
}
public void clear(){
listItems = null;
listItems = new ArrayList<ListRowObject>();
notifyDataSetChanged();
}
#Override
public int getCount() {
return listItems.size();
}
#Override
public Object getItem(int position) {
return listItems.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup viewGroup) {
ViewHolder holder;
if(convertView == null){
holder = new ViewHolder();
convertView = activity.getLayoutInflater().inflate(R.layout.list_row, null);
holder.text = (TextView) convertView.findViewById(R.id.text);
holder.bgLayout = (LinearLayout) convertView.findViewById(R.id.bgLayout);
convertView.setTag(holder);
}else{
holder = (ViewHolder) convertView.getTag();
}
ListRowObject row = listItems.get(position);
if(row.isSelected())
holder.bgLayout.setBackgroundColor(Color.GRAY);
else
holder.bgLayout.setBackgroundColor(Color.WHITE);
holder.text.setText(row.getText());
return convertView;
}
}
//--------
public class ListRowObject {
private String text;
private int positionInList;
private boolean isSelected;
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public int getPositionInList() {
return positionInList;
}
public void setPositionInList(int positionInList) {
this.positionInList = positionInList;
}
public boolean isSelected() {
return isSelected;
}
public void setSelected(boolean selected) {
isSelected = selected;
}
}
//------
public class Main extends Activity {
private ListView listView;
private ListAdapter adapter;
private Activity activity;
private ArrayList<ListRowObject> items;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
activity = this;
initializeFormViews();
initializeOnClickEvents();
fillList();
}
private void initializeFormViews(){
listView = (ListView) findViewById(R.id.listView);
}
private void initializeOnClickEvents(){
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
Toast.makeText(activity, "Pressed " +position, Toast.LENGTH_SHORT).show();
// unselect all rows
for(ListRowObject item : items){
item.setSelected(false);
}
int first = adapterView.getFirstVisiblePosition();
int last = adapterView.getLastVisiblePosition();
int centerPosition = (first + last) / 2;
// change bg for centerPosition row
adapterView.getChildAt(centerPosition).findViewById(R.id.bgLayout).setBackgroundColor(Color.GRAY);
changeItems(position, centerPosition);
}
});
}
private void changeItems(int pressedPosition, int centerPosition){
ListRowObject centerRow = items.get(centerPosition);
ListRowObject pressedRow = items.get(pressedPosition);
pressedRow.setSelected(true);
centerRow.setSelected(false);
items.remove(centerPosition);
items.add(centerPosition, pressedRow);
items.remove(pressedPosition);
items.add(pressedPosition, centerRow);
adapter.clear();
adapter.addItems(items);
}
private void fillList(){
adapter = new ListAdapter(activity);
items = new ArrayList<ListRowObject>();
items = getItems();
for(ListRowObject item : items){
adapter.addItem(item);
}
listView.setAdapter(adapter);
}
private ArrayList<ListRowObject> getItems(){
ArrayList<ListRowObject> result = new ArrayList<ListRowObject>();
for(int i = 0; i < 15; i++){
ListRowObject object = new ListRowObject();
object.setPositionInList(i);
object.setText("Item #" + i);
if(i != 4)
object.setSelected(false);
else
object.setSelected(true);
result.add(object);
}
return result;
}
}
//------
public class ViewHolder {
public TextView text;
public LinearLayout bgLayout;
}
list_row.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="50dp"
android:id="#+id/bgLayout">
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:id="#+id/text"
android:textColor="#000000"
android:textSize="24dp"
android:gravity="center"/>
</LinearLayout>
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/listView"/>
</LinearLayout>

when you create ArrayAdapter for your listview you send a ListArray to it.when you want change content .you only change this listArray then when click your item you can change ListArray and call notifyDataSetChanged(); method your adapter.

ListActivity CustomAdapter error, onListItemClick never works

Below you can see the code, i implemented a simple adapter for my listview. But i can not get in to onListItemClick. can anyone has suggestions ?
actually it displays the list normally but i am not able to get onitemclick events . thanks in advance.
public class MyListActivity extends ListActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ArrayList<Frame> results = WebOperations
.loadList_Frame();
myAdapter = new MyListAdapter(MyListActivity.this);
myAdapter.internalList = results;
setListAdapter(myAdapter);
myAdapter.notifyDataSetChanged();
};
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
String item = (String) getListAdapter().getItem(position);
Toast.makeText(this, item + " please show toast!!!!!!!!!", Toast.LENGTH_LONG).show();
}
public static class MyListAdapter extends BaseAdapter {
public ArrayList<Frame> internalList;
public LayoutInflater mInflater;
public int pageCount = 0;
public MyListAdapter(Context context) {
mInflater = LayoutInflater.from(context);
}
public int getCount() {
if (internalList == null)
return 0;
return internalList.size();
}
public Object getItem(int position) {
if (internalList == null || internalList.size() < position)
return null;
return internalList.get(position);
}
public long getItemId(int position) {
if (internalList == null || internalList.size() < position)
return 0;
return internalList.get(position).getId();
}
public View getView(int position, View arg1, ViewGroup parent) {
View v = arg1;
if ((v == null) || (v.getTag() == null)) {
v = mInflater.inflate(R.layout.entryrow, null);
try {
String gunlukText = String.format(" %s ",
internalList.get(position).getKeyText().toString());
TextView entry = (TextView) v
.findViewById(R.id.textViewEntryText);
entry.setText((CharSequence) gunlukText);
} catch (Exception e) {
Log.d("aaaaaaaaaaaaaaaaaaa", "errorrrrrrrrrrr");
}
}
return v;
}
}
}
EDIT 1 : I am adding entry_row layout xml file below.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/textViewEntryText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textMultiLine"
android:padding="5dp"
android:paddingLeft="10dp"
android:text="#string/Ana_Sayfa"
android:textAppearance="?android:attr/textAppearanceMedium" />
</LinearLayout>

You should consider adding your listener to your listview :
getListView().setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String item = (String) getListAdapter().getItem(position);
Toast.makeText(this, item + " please show toast!!!!!!!!!", Toast.LENGTH_LONG).show();
}
});

add onclicklistener into getView method just before return view.
v.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Log.w("position", position + "");
}
});
check if it helps..

Didi you try, on your layout/entryrow, to add the addStatesFromChildrenattribute and set it to true ?
http://developer.android.com/reference/android/view/ViewGroup.html#attr_android:addStatesFromChildren

Please refer one of the good example given in API demo of custom BaseAdapter from http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/List13.html Just override onListItemCLicked and check. It works perfectly fine. Try to modify your code accordingly.

Android: HowTO delete last item of a list and the list

I have an activity which extends ListActivity. It has many things but amongst them it shows the articles the user has purchased with an adapter. Well I have a method that the user can delete the items from the list. The problem is when there is only one item. If I try to delete the last one the app crashes. Here is a it of my code:
public class Ventas extends ListActivity {
......
lv = getListView();
......
protected void confirmRemoval(final int arg2) {
// TODO Auto-generated method stub
AlertDialog alertDialog = new AlertDialog.Builder(this).create();
alertDialog.setTitle(getResources().getString(R.string.ventas));
alertDialog.setMessage(getResources().getString(R.string.confirmacion2));
alertDialog.setButton("Si",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
if(adapter2.mEvents.size()>=1){
adapter2.mEvents.remove(arg2);
} else {
//doesn't work
/*adapter2=null;
adapter2.notifyDataSetInvalidated();
lv.setVisibility(View.GONE);*/
}
}
});
alertDialog.setButton2("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
alertDialog.show();
}
here is the adapter and wrapper:
private class EventAdapter2 extends BaseAdapter {
public ArrayList<Articulo> mEvents = null;
public EventAdapter2(Context c, ArrayList<Articulo> clientes) {
mContext = c;
mEvents = clientes;
}
public int getCount() {
return mEvents.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
EventEntryView2 btv;
if (convertView == null) {
btv = new EventEntryView2(mContext, mEvents.get(position));
} else {
btv = (EventEntryView2) convertView;
String title1 = mEvents.get(position).getCantidad() + "";
if (title1 != null) {
btv.setText1Title(title1);
}
String title2 = mEvents.get(position).getDescripcion();
if (title2 != null) {
btv.setText2Title(title2);
}
String title3 = mEvents.get(position).getpVenta() + "0";
if (title3 != null) {
btv.setText3Title(title3);
}
String title4 = (mEvents.get(position).getCantidad() * mEvents
.get(position).getpVenta()) + "0";
if (title4 != null) {
btv.setText4Title(title4);
}
}
return btv;
}
private Context mContext;
}
private class EventEntryView2 extends LinearLayout {
private TextView text1;
private TextView text2;
private TextView text3;
private TextView text4;
private View inflatedView;
public EventEntryView2(Context context, Articulo resp) {
super(context);
this.setOrientation(VERTICAL);
inflatedView = View.inflate(context, R.layout.results, null);
text1 = (TextView) inflatedView.findViewById(R.id.textView1);
text2 = (TextView) inflatedView.findViewById(R.id.textView2);
text3 = (TextView) inflatedView.findViewById(R.id.textView3);
text4 = (TextView) inflatedView.findViewById(R.id.textView4);
String t = resp.getCantidad() + "";
text1.setText(t);
String t1 = resp.getDescripcion();
text2.setText(t1);
String t2 = resp.getpVenta() + "0";
text3.setText(t2);
String t3 = (resp.getCantidad() * resp.getpVenta()) + "0";
text4.setText(t3);
addView(inflatedView, new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
}
public void setText4Title(String title4) {
text4.setText(title4);
}
public void setText3Title(String title3) {
text3.setText(title3);
}
public void setText2Title(String title2) {
text2.setText(title2);
}
public void setText1Title(String title1) {
text1.setText(title1);
}
}
as you can see when I have only one item left I have tried to set adapter to null or adapter.notifyDataSetInvaliadted or even making the listview invisible, nothing works. What happens is when I click ok nothing changes then when I click a second time it all crashes
What I would like is the listView to disappear when the adapter is empty but I am now out of ideas, is it even possible?
Any ideas?
EDIT:
Thank you all for the answers but the problem was I was modifying the list from inside an inner anonymous class. It is actually pretty simple, create a method and call it from inside the dialog, once the array is empty the list disappears automatically:
protected void removeFromList(int arg2) {
adapter2.mEvents.remove(arg2);
adapter2.notifyDataSetChanged();
}

remove item from the arraylist which you add into the adapter and then call this method.
youradapter.notifyDataSetChanged();
and whatever you do for single item that was
adapter2 = null;
adapter2.notifyDataSetInavlidated();
this will obviously crash it because adapter2 object was null so how null object notify its data

Try calling lv.invalidate() after the remove() and see whether that makes any difference.

You should check in your adapter class if it is null then you should not fetch value from it......that's the main reason why you are getting exception as you are fetching the value from null variable.Put check there.

For setVisibility to Work:
You create your main.xml
Add to it a ListView
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res/sherif.android.deedz"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView android:layout_width="match_parent"
android:layout_height="match_parent" android:id="#+id/myListView"
android:divider="#ffa500" android:dividerHeight="1px"
android:background="#drawable/somedrawable_xml"
android:choiceMode="singleChoice"></ListView>
</ListView>
Now you can make it GONE
If you want the whole details of this :
Check my answer