Develop Reference

android studio. i ask about the use of on item click listener function. how it work?

ListView listView;
ArrayAdapter<String> adapter;
String[] hotel = {"one room", "double room", "suit", "vip"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView);
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, hotel);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Toast.makeText(getApplicationContext(),adapterView.getItemIdAtPosition(i)+"is Checked",Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(),adapter.getItem(i),Toast.LENGTH_LONG).show();
}
});
}
Could anyone explain to me how on item clickListener work? what View view , int i , long I mean on (onclick item listener?. A new Adapter view class or object?

OnItemClickListener is a Listener which keep listening for the events. When you click any item in the ListView then this interface will fired and it'll call the onItemClick callback(abstract method). So just override this method and put your code which needs to run when the item is clicked. In your case, you're just showing the item id with Toast.
onItemClick : It is a Callback method in Android. This can be invoked when an item in this ListView has been clicked.
This method accepts four parameters adapterView, view, i, l
AdapterView(adapterView): The AdapterView where the click happened. This might be a ListView, GridView etc. These classes are derived from the AdapterView class.
View(view): The view within the AdapterView that was clicked (this will be a view provided by the adapter). The View parameter passed in the onItemClick() method when you click the item in the ListView.
int(i): The position of the view in the adapter. By this way, you can get the item. Position starts from 0 to n.
long(l): The row id of the item that was clicked.
Please see this documentation. Hope this helps you...

setOnItemclicklistner for simplelistitem1 or simplelistitem2

I am using android built in layout android.R.layout.simple_list_item 2. I wanted to perform onItemclicklistner() for the items in this layout. I couldn't find the resource id for this layout without which I couldn't find a way to perform the listner function. The examples I have seen so far is
ListView list = (ListView) findViewById(R.id.mylist); // Since I am using built in layout I couldn't figure out the resourse id as in this case.
list.setOnItemClicklistner();
So my problem is without knowing the resourse id of the built in layout "simple_list_item 2" how can I create a Listview object. and without having a ListView Object I am unable to access setOnItemClickListner(). Hope I delivered the question in a meaningful way. Thanks

Use setOnItemClickListener() instead of setOnClickListener()

If you want to perform clicks on items in the ListView, try using OnItemClickListener in place of OnClickListener. The OnItemClickListener can be set on the ListView as shown below.
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
// Perform the required tasks here
}
});

for list item click u should set onItemClickListener like below
listview.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> a, View v, int position,
long id) {
}
});
also you can set onItemClickListener Interface to your Activity and override method in activity

use setonItemClickListner();
listview.setOnItemClickListner(new OnItemClick(){});

setOnItemClickListener not updating with notifyDataSetChanged

I'm using notifyDataSetChanged with my custom GridViewAdapter which updates the listView however when I click on something with my updated listView, the old links are still there. I have the following ClickListener in my onCreate method.
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent intent = new Intent(getBaseContext(), SpiceList.class);
intent.putExtra("INGREDIENTS_CALL", true);
intent.putExtra("INGREDIENTS_SELECTED", position + 1);
if (recipeCall) {
intent.putExtra("RECIPE_CALL", true);
}
startActivity(intent);
}
});
I've tried duplicating this inside the buttons that update the listView but this does not work. Any ideas for how I can best update my listener to reflect my changed listView?
Thanks! :)

Not sure if i understand your question but let me see if i can try. You are changing the listviews views when you click on one?
Are you deleting any element in the array or List you are using for your adapter? So you remove an item and then call notifyDataSetChange()? or you add an item to the array and call the notify method?

Turns out the problem was in the way I was retrieving my SQL queries. I was making the position of my listener equal to the ID of the SQL entry I was retrieving. Therefore, even though my list changed, item 1 was still pulling SQL items with an ID of 1.
When I designed my queries in Android, I originally did not expect that I would run into this problem. However, now I've linked my SQL queries to the actual item ID and not the listener position. My new listener is now:
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent intent = new Intent(getBaseContext(), SpiceList.class);
intent.putExtra("INGREDIENTS_CALL", true);
intent.putExtra("INGREDIENTS_SELECTED", Integer.parseInt(resultsID.get(position)));
if (recipeCall) {
intent.putExtra("RECIPE_CALL", true);
}
startActivity(intent);
}
});
Thanks for your help!

Working with LazyList by Fedor onitemclick implementation

I will sound stupid to most of you by asking this, but I haven't been able to figure it out on my own and can't pass to my next task until I found an answer.
So far I have downloaded the LazyList project from https://github.com/thest1/LazyList made by Fedor, I'm trying to understand how it works so I can implement it on my own project. My problem is that I don't know where to implement the onitemclicklistener part:
AdapterView.OnItemClickListener onitemClick = new AdapterView.OnItemClickListener()public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
noteId= //the item id from the list
Toast.makeText(getApplicationContext(), noteId, 2000).show();
}
I have try to add it on my mainActivity but then I can't find how to connect to my LazyAdapter to find the item id to be displayed in a toast. My project will contain some other information in the list (as a table several columns) so I want to be able to access an specific columns from that rows using the item id. and testing with a simple toast will help.
Thanks, I hope you don't laugh to much and help me a little.

I think you are going about it in the wrong manner: AdapterView.OnItemClickListener is an interface and the onItemClick() method takes four parameters... I assume this is what you are trying to do:
ListView listView = (ListView) findViewById(R.id.list);
listView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getApplicationContext(), id + "", 2000).show();
}
});

Get reference to an object within a ListView

Up front: This is my first attempt at an Android app. I'm in that strange place of not knowing what to search for to find the answer to my question.
What I have accomplished is:
Created a custom class myCustomClass with properties of 'title' and 'youTubeUrl'
Created an ArrayList<myCustomClass>
Added multiple elements to ArrayList<myCustomClass>
Created a custom ArrayAdapter and attached it to the the arraylist.
Added an onItemClickListener to the custom ArrayAdapter.
All of that works good. I would like to show the title in the ListView and then when the user clicks the list view item, I'd like to get a reference to the youtubeUrl property.
Here's what I have for the adapter code:
MyListAdapter myListAdapter = new MyListAdapter(this, R.layout.my_list, elements);
myList.setAdapter(myListAdapter);
myList.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String item = ((TextView)view).getText().toString();
Toast.makeText(getBaseContext(), item, Toast.LENGTH_LONG).show();
}
});
myListAdapter.notifyDataSetChanged();
Thanks for your help.

You can use the position property in onItemClick to go back to your data source and find the relevant item. From there you should be able to retrieve the Url.

As another poster implied, it depends on what you are using in your adapter. Assuming it's MyCustomClass. You can do something like this in your onItemClick method:
MyCustomClass selection = (MyCustomClass) getListView().getItemAtPosition(position);