Develop Reference

AutoCompleteTextView Drop Down list shows empty textViews

I have written the following code for populating the AutoCompleteTextView from a MySQL database using internet. The database returns data and autocompletetextView adapter contains that data, however the drop down list shows empty cells.
if(suggestionList != null)
{
Toast.makeText(getApplicationContext(), "Contains Data", Toast.LENGTH_SHORT).show();
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_dropdown_item_1line,suggestionList);
searchBox.setAdapter(adapter);
for(int i=0; i<suggestionList.length;i++)
System.out.println(suggestionList[i]);
}
NOTE:
SuggestionList is a String array and contains all the data
What can be the issue here?
Regards

Try this..
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, suggestionList);
searchBox.setAdapter(adapter);
searchBox.setThreshold(1);

As reference you could take a look here:
https://github.com/dentex/AutoCompleteTextView-with-SQlite
It stores user searches into the DB and retrieves them as you type.

Try adding items to your adapter manually.
For example:
adapter.add("Item 1");
Refer to documentation for adding items in the list view.

Android null pointer exception on ArrayList for ListView

I have a listview that shows the contents of an arraylist. I'm using a simple adaptor to make this possible like so.
public static ArrayList<String> homeScreenContacts = new ArrayList<String>();
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
R.layout.home_screen_contacts_view, NewContact.homeScreenContacts);
The second line is giving me a null pointer exception. I thought about it and I decided it was because the arrayList is empty. So I added the following line between the arraylist declaration and the arrayadaptor declaration...
NewContact.homeScreenContacts.add("A Contact");
This solved the problem and my code worked fine but Now the list view shows "A Contact" and I dont want it to. Is there anyway to get rid of the null pointer exception problem but still have the arraylist empty? Because I want to populate it with user made contacts, not hard-coded, random strings. Thank you.
EDIT: Sorry, The arraylist is located in another class called NewContact, also, I am very beginner Android Programmer I just started.

Simple solution just don't initialize the ListView if there is no element in the ArrayList or the ArrayList is null.
if(NewContact.homeScreenContacts != null && NewContact.homeScreenContacts.size() > 0){
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
R.layout.home_screen_contacts_view, NewContact.homeScreenContacts);
listView.setAdapter(adapter);
}
Also you need to remember that if you you haven't initialize Adapter then dont initialize the ListView and before any operation on list view you should check is it null or not.
As you have said that you want to populate when user add some contact in the application then on add event only you need to populate or update the ListAdapter.
Hope this solution will resolve your problem.

Try this code
public class YourActivity extends Activity
{
private ListView lv;
public void onCreate(Bundle saveInstanceState) {
setContentView(R.layout.your_layout);
lv = (ListView) findViewById(R.id.your_list_view_id);
// Instanciating an array list (you don't need to do this, you already have yours)
ArrayList<String> your_array_list = new ArrayList<String>();
your_array_list.add("foo");
your_array_list.add("bar");
// This is the array adapter, it takes the context of the activity as a first // parameter, the type of list view as a second parameter and your array as a third parameter
ArrayAdapter<String> arrayAdapter =
new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, your_array_list);
lv.setAdapter(arrayAdapter);
}
}

Works fine for me:
if(arrayList.isEmpty())
{
listView.setAdapter(null);
}
else
{
listAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,arrayList);
listView.setAdapter(listAdapter);
}

Spinner data sorting in Android

I have spinner with array list thats work fine, but i want to sort out the datas from a to z (example: apple,ball,cat,dog...)order. I submit my code below
ArrayList<String> SourceArray = new ArrayList<String>();
Spinner Sourcespinner;// = new Spinner(this);
Sourcespinner = (Spinner)findViewById(R.id.Spinner1);
ArrayAdapter<String> SourceArrayAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item,SourceArray);
SourceArrayAdapter.add("Chennai");
SourceArrayAdapter.add("Mumbai");
SourceArrayAdapter.add("Kolkatta");
SourceArrayAdapter.add("Delhi");
Sourcespinner.setAdapter(SourceArrayAdapter);`
I don't know how to do sorting for this

you can use this to sort your data
Collections.sort(SourceArray);

Try to add data to the ArrayList and just use the Collections class to sort for you:
Collections.sort(SourceArray);
If you need to add your own objects they need to implement the Comparable interface and implement the method compareTo(). When changing the ArrayList's data make sure to notify the adapter that new data might have been added by using this code:
SourceArrayAdapter.notifyDataSetChanged();

spinner with no select option

I'm trying to create spinner which should not have any select but instead of it, it should show Blank, after clicking that items can be selected.
Here is my code, please help.
urineGlucoseSpinner = (Spinner) view.findViewById(R.id.spnner_urine_glucose);
ArrayList<String> ugList = new ArrayList<String>();
ugList.add(0,"");
ugList.add("1.5");
ugList.add("5.5");
ugList.add("0.8");
ugList.add("9.5");
ugList.add("12.0");
//ArrayAdapter<String> urineGlucoseAdapter = new ArrayAdapter<String>(getActivity(),android.R.layout.simple_spinner_item, ugList);
ArrayAdapter<String> urineGlucoseAdapter = new ArrayAdapter<String>(getActivity(),R.layout.custom_spinner_text, ugList);
urineGlucoseAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
urineGlucoseSpinner.setAdapter(urineGlucoseAdapter);
urineGlucoseSpinner.setSelection(0);
urineGlucoseSpinner.setOnItemSelectedListener(new OnUGItemSelected());

By default spinner takes array 0th element if u not selecting any one..u have to make object of ArrayList and for 0th element u have to put "" (null Sting) inside semicolon and make it as 0th element...i think this is the only solution for your question..
ArrayList<String> ugList = new ArrayList<String>();
ugList.add("");

I can see two ways to do this.
1) Add the blank line to your data at position 0, and then create a custom spinner adapter and override the getView method and in it use an if to set the 0 position view to GONE (thus getting rid of the blank line in the listing).
2) An alternative might be setting an empty EditText in your form, and when it gains focus pop a listview in a dialog with your possible choices.

How do you add array to listview

I have an array of apps(PInfo) and I am wondering how do I add that array to a listview?
ArrayList<PInfo> info = appsGetter.listPackages();
int number = 0;
PInfo appInArray;
while(number < info.size()){
appInArray = info.get(number);
}
This is what I have at the moment, the listPackages() is a method that is getting the names of the apps from the device.
At the moment I am trying to get the information out of the array one by one and add it to the listview like that. Is that how I should do it our should I add the array straight to the listview? And how do you do that?

You can use an ArrayAdapter and initialize it like this:
ArrayAdapter<PInfo> adapter = new ArrayAdapter(context,
android.R.layout.simple_list_item_multiple_choice,
info);
Then you can you use ListView.setAdapter(adapter).
I'm not sure if this is what you're asking though. So please clarify further if this is not what you're asking

Try using an Adapter. For example (using just the String value of an object) you could do the following:
ListView listView = (ListView)findViewById( R.id.myListView );
final ArrayList<String> listItems = new ArrayList<String>();
final ArrayAdapter<String> adapter = new ArrayAdapter<String>( this, android.R.layout.simple_list_item_1, listItems );
listView.setAdapter( adapter );
Just a quick example, but I hope it gives you a starting place. Just make sure if you add values to your data source later (in this case the ArrayList) to call the adapter's "notifyDataSetChanged()" method so that it can be properly reflected in whatever has been bound to the adapter (in this case the ListView).

You need to use an ArrayAdapter. Just search for a ListView and ArrayAdapter sample online. It's quite simple once you see it done.