Develop Reference

How to modify a ListView item in Android?

I'm starting learning Android and I want to know if there is some option in Android that let you modify each item or view (I don't know how it's named exactly, I mean each of the items from an ArrayList that you show in a ListView).
Well, I made a ListView that is going to show some books that were located in an ArrayList named "books".
I made a custom adapter that I associate to the ListView to show each item with the corresponding layout in the application. I also have a class "book" for each item that is going to be shown in the ListView.
Further, I made an Intent that I call from MainActivity with startForActivityResult(), that I process in Book class and that I return to MainActivity with all data of a book with the method setResult and got the information with onActivityResult() and the requestCode.
So I don't have any problem to add items to the ListView, just I have the problems if I want to modify some of the items (or views) that are located in the ListView (for example if I have title and author of a book, if I put some wrong information, I want have the option to change it).
I have that, in the same moment that you click on some of the items of the ListView, a new layout will be show to modify the information that it's wrong so I use the method setOnItemClickListener with onItemClick event on the custom adapter that I created before. Here it's where I call the new Intent to modify the wrong information with the method startActivityForResult().
I made the same as before to add a new item but, instead of add a new item with custom_adapter.addBook(title,author) I want to know if there is some option to made something like this: custom_adapter.modify(title,author) or custom_adapter.update(title,author), I mean, when you have modify all the items that were wrong of a book (for example an EditText that were "title") and you have all the information in the MainActivity class (because you returned it with setResult), how to put it again in the same item updating it in the custom_adapter and also in the ArrayList.
I searched it on the Internet but I didn't find anything.
I'm sorry if I have a poor English, but I expect that it can be understand.
Thank you very much!

If I am understanding your problem correctly - you could simply modify the ArrayList of type Book that is backing your ArrayAdapter.
So if you know what Book object you want to modify then you can simply make your changes to the Book object itself. As long as this Book is a reference to the same object that you originally added to the ArrayList you instantiated your ArrayAdapter with then you can then call custom_adapter.notifyDataSetChanged() to tell the adapter to redraw its childviews with the new data.

There are some good code samples on the Internet but you have to understand the code for your purposes. So...here is a start, look at Using an ArrayAdapter with ListView. The code shows the use of ArrayAdapter with getView() method. And I hope it shows how to define the listeners, which you need.
How about that for a start? Have fun...

Thank you very much for all help you gave to me. I'm very pleased with you. :)
Finally, I just send the info with a Bundle when I started the Intent, also with the position. And after, I just used this position to set the new info to my items (in my case, books).
Again, thank you very much ;)

Android Custom ListView/Adapter

I am wanting to change my listView from the normal ArrayAdapter (simple_list_item_1) to something more like this:
Name..... Score(center right).
Date (under name)
So There's 3 Views...
name
date
score
I've looked up how to make custom adapters and layouts but they are all very confusing. I just want a simple fix that I can add to an existing project.
Here's my code for my list right now:
//update listView
listAdapter = new ArrayAdapter<String>(GradesActivity.this, android.R.layout.simple_list_item_1, names);
mListView.setAdapter(listAdapter);
Help is appreciated!

I just had the SAME problem last week. My solution was a tutorial on the internet: http://androidtuts4u.blogspot.com.br/2013/02/android-list-view-using-custom-adapter.html
Just copying and pasting the code onto a temporary project (it will take less than 15 minutes) will help you understand how simple it is and also make it very clear so you can implement it into your original project. I hope it helps!
Peace!

ArrayAdapter can't auto binding three view
You can try SimpleAdapter or extend BaseAdapter implements it youself
This is Google's training
https://developer.android.com/training/material/lists-cards.html
https://developer.android.com/training/wearables/ui/lists.html
And here is a sample of SimpleAdapter http://www.java2s.com/Code/Android/UI/UsingSimpleAdaptertofilldatatoListView.htm

There are many fixes you need to do
1. Create a class that extends BaseAdapter.
Override all the methods create a constructor of that class that will initialize listitems
You are just passing names
listView listAdapter = new ArrayAdapter(GradesActivity.this, android.R.layout.simple_list_item_1, names);
Instead of just names create a class that contains three elements you need I.e name date and score and make there get and set methods
And the object of the class will be saved in a list.
4. In getview method you have to set these variables

StableArrayAdapter vs ArrayAdapter

I am looking at this ListView Tutorial:
ListView Tutorial
and I was wondering how much better is to create my own ArrayAdapter, rather than just using and ArrayAdapter.
In the Tutorial it defines a "StableArrayAdapter", what exactly does this means? If I use a regular ArrayAdapter, could it be dangerous for some reason?

The two previous answers are absolutely right, but just to address more directly your question and in case someone else has the same doubt than you; a regular ArrayAdapter is not dangerous at all, the only "problem" is that it might not fulfill your needs, in which case you will have to create your own adapter, as the author of the tutorial did by creating what he called StableArrayAdapter in the end of the ListViewExampleActivity class.
Don't get lost by the name, which I guess comes from the fact that the overwritten method "hasStableIds" always returns true, it doesn't mean that the regular ArrayAdapter creates problems.

ArrayAdapter: It is merely a way to provide data to a ListView. It is also a BaseAdapter that is backed by an array of objects.
CustomAdapter: If if your ListView is a normal and simple ListView (wherein you are having one TextView per item in the list), then the use of ArrayAdapter would be apt.
But it is recommended you to create your own CustomAdapter which extends an ArrayAdapter that you can use for providing data to your ListView. This way you can easily extend your ListView to include more that one TextView or even ImageView (to show images).
CursorAdapter: Cursor Adapter is used when you have Data in a Cursor (typically when you are retrieving data from a database. The Cursor must include a column named "_id" or this class will not work.

If you are using a simple ListView, like merely a TextView per item, then just use the standard ArrayAdapter, on the other hand, if you want a custom item in the list, as in a combinations of views within each item in the ListView, then extend the ArrayAdapter and implement it to your needs.

StableArrayAdapter is merely an extended version of ArrayAdapter, but in StableArrayAdapter they have overridden the method hasStableIds() of BaseAdapter to return true.
You can check this in the following links:
StableArrayAdapter -
Override hasStableIds to return true
ArrayAdapter -
Has not Override hasStableIds but extended BaseAdapter
BaseAdapter -
Has hasStableIds but returning false
Now Question is What is the use of StableIds
This Indicates whether the item ids are stable across changes to the underlying data. If True then same id always refers to the same object. for more info

Setting tags to each item in a ListView in Android?

I have a ListView where I want each item to have an ID number attached to it (not the same as the position number). I was hoping this could be done by setting a tag to each View item in the ListView using setTag() when these Views are being created.
Right now I'm creating the ListView like this:
final ListView listview = (ListView) findViewById(R.id.listView1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, names);
listview.setAdapter(adapter);
The names variable in the ArrayAdapter parameters above is an ArrayList, and each string value in this list also has a unique ID that I want to link to this string somehow.
Is there any way I can get access to and modify each of the Views with a tag? One idea was to create my own extended class of ArrayAdapter and override the getView() method, but I don't really understand how it works and how I would go about doing this.
Or is there a better way to link IDs with each string like this than adding tags like I'm trying to do?

Create a ViewBinder and set the tags as the ListView is being populated with whatever you need. You can check all properties of the view to determine what tag goes where, so this should be what you're looking for.
myAdapter.setViewBinder(new MyViewBinder());
public class MyViewBinder implements ViewBinder {
#Override
public boolean setViewValue(View view, Object data, String text){
//Since it iterates through all the views of the item, change accordingly
if(view instanceof TextView){
((TextView)view).setTag("whatever you want");
}
}
}
I just used this exact same answer on another question (albeit slightly different) yesterday.

about getView , it works by using a method of recycling views. i will try to explain it in a simple way.
suppose you have tons of items that can be viewed . you don't want to really create tons of views too , since that would take a lot of memory . google thought of it and provide you the means to update only the views that need to be shown at any specific time.
so , if there is an empty space on the listview , it will be filled with a new view . if the user scrolls , the view that becomes hidden is recycled and given back to you on the getView , to be updated with the data of the one that is shown instead .
for example , if you scroll down , the upper view becomes hidden for the end user , but in fact it becomes the exact same view that is on the bottom .
in order to understand how to make the listview have the best performance and see in practice how and why it works as i've talked about , watch this video:
http://www.youtube.com/watch?v=wDBM6wVEO70
as for tags , i think you want to do something else , since the data itself (usually some sort of collection, like an arrayList) already knows where to update , because you get the position via the getView . if you want a specific view to update , you might be able to do so by using a hashmap that keeps upadting , which its key is the position in the collection , and the value is the associated view . on each time you go to getView , you need to remove the entry that belong to the view (if exists) and assign the new position with the view that you got/created .

Thanks for the answers. thisMayhem's answer would probably have been easier in the end, but on my quest to learn more I ended up making my own adapter according to this tutorial. I pass down the names and the IDs into the adapter and set the names as the text of the TextViews and the IDs as the tags.

I would rather go with the solution discussed in this thread. It is always the easiest to have all related data in same place and in this case you just create a class to hold all the information you will need for every item.

showing multiple values of an object in a row

I am having a List of objects in my activity class.
want to show objects in a list containing attributes of the object in a row.
for example :
a.1 a.2 a.3 a.4
b.1 b.2 b.3 b.4
c.1 c.2 c.3 c.4
.....
.....
vertically the list should be scrollable.
for showing single value in a row I am sucessfully using :
setListAdapter(new ArrayAdapter(this, R.layout.project_list,titles));
Kindly suggest the available solutions.
Thanks in advance.

to do that just go to these like at list for me it worked ok http://www.softwarepassion.com/android-series-custom-listview-items-and-adapters/
Happy Coding