Is there a way to do this? My specific purpose is that I am trying to populate a label from an edittext within my list that is populated by a simplecursoradapter. When I gather the information from the cursor is only gives me the value from the most recent item in the list.
Example:
lbs = (TextView)view.findViewById(R.id.GrainLbs);
lbs.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View v, MotionEvent arg1) {
if(!popState){
parentActivity.showPopup(v, mView, getId, String.valueOf(getLbs));
Log.i("Current ID", "");
}
setPopState();
return true;
}
});
I'm trying to pass the value from the database to a method in my activity from within my custom simplecursoradapter (String.valueOf(getLbs)) which since i'm gathering this information by clicking on an object in the listview I thought it would automatically use the data from the specific list item. Is there a way I can get the list item position and then use info from the database based on the position?
If you are extending ListActivity, then you can override ListActivity.onListItemClick. The second argument passed into that function is the position in the list, which is the same as the position in your SimpleCursorAdapter.
This turned out to be such a simple answer and I can't believe i've spent so much time trying to figure it out. Because I was collecting the value within an inside method (an onclicklistener) I needed to make my variable final, it was declared at the beginning of the class so it could be used throughout, and because of this I wasn't getting an exception, but I needed to make it final before it would pass the correct value for whatever reason.
So I guess if you bind your views within a customcursoradapter you can collect values for each individual listitem without knowing the position, it automatically knows this for you.
Related
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I found a tutorial about using the ListView in android. But I have a question about it. Here the tutorial:
http://www.vogella.com/articles/AndroidListView/article.html#listadvanced_interactive
You have to scroll to section 13.2.
The idea of the tutorial is on one hand you have a ListView (with checkboxes in each item), on the other hand you have an ArrayList (the items of the ArrayList are objects, which contain the information which are displayed in the items of the ListView, e.g. CheckBox checked or not, text etc.). The adapter schould keep both things equal. If you change the ArrayList, the ListView will be changed, too.
But now my question. If the user touch on one item of the List, the adapter will call the method "onCheckedChanged". But what happen there? An object will create there and get a tag from the the CheckBox. Ok. Now the method is done. The garbage collector will destroy the object or doesn't? What is when I need this infomation from there in my Activity. Imagine I have a button "Delete" under my list. So I have to transfer these information from the listener of the adapter to my Activity. How I can ensure that I use the same ArrayList with the right information in every class?
#Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
Model element = (Model) viewHolder.checkbox
.getTag();
element.setSelected(buttonView.isChecked());
}
I hope you know what I mean. Can you explain it to me please?
Sorry for the language, but english isn't my mother tongue.
Bye
If I understand your question, the response is in the Chapter 14.1 of the tutorial you gaved...
If you want to do some treatment when delete is checked you add a listener in the ListView.
These functions normally have the position clicked and you can do whatever you want knowing the position clicked. For exemple:
list.setOnItemLongClickListener(new OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(MyList.this,
"Item in position " + position + " clicked",
Toast.LENGTH_LONG).show();
// Return true to consume the click event. In this case the
// onListItemClick listener is not called anymore.
return true;
}
});
I'm not totally sure I understand you're question. There's a lot to unpack in there but I will give it a shot. To understand what's going on you need to understand the relationship between the ListView and the data that backs it which is contained in the ListAdapter.
The ListView displays the data contained in the ListAdapter. The ListAdapter gets its data from some other source, in this case its the ArrayList that you're referring to. Why use an ArrayList? In the tutorial its not entirely clear because the example uses a fixed set of data (e.g. a list of operating systems) that are written out as strings. In practice, however, often times you are using a dynamic list, like a list of users, places, whatever.
The ArrayList holds the objects that will eventually be displayed. This is the "models" class in the tutorial. The same applies for any other class of data, like a list of places. If you imagine a place as a class, that class would contain fields that describe the place (e.g. address, a description, some other unique features). As data is downloaded from some location, a new instance of place would be created for each location. Those objects would be collected in an ArrayList. When the downaloding process was finished, you would then begin the process of passing the contents of that ArrayList to the ListAdapter so that the ListView could eventually be updated.
How do you know you will always use the right ArrayList? Because your ArrayList is linked to you ListAdapter. The data the the ListAdapter processes, whether a list of models or users, is supplied by the ArrayList. You cannot use the wrong one. The same goes for the ListAdapter. Because you must set the adapter that the ListView is linked it it will always pull from the correct source. You cannot use the wrong data.
What's happening with the onCheckChanged listener, if you pay close attention, is that the user is really just updating a field contained in the model class. Each modle has an isChecked field. When the check box is clicked, that value for the object is updated. This is how you know what is checked and what is not.
Response to: "Nobody told the adapter "Hey it belongs to the list, which is your source"
Look at the documentation for ArrayAdapter
and for ListView
The constructors for the ArrayAdapter all take some list of object as an argument. This list would be the list of object that will be displayed within the ListView.
Additionally the ListView requires that you call setAdapter which takes some ListAdapter as its argument. This is what actually tells the ListView the source of the data it is going to display.
In that sense, the List, ListAdapter, and ListView are all linked together.
I have a list of items which is fetched from the local database. Every item has property isNew. I want to make visible TextView with text "new" only for items which match isNew = true. I solve this problem with two ways, and now I want to know which is best method.
Method 1:
I write a class MyViewBinder which implements SimpleCursorAdapter.ViewBinder and overrides public boolean setViewValue(view, cursor, columnIndex) method with my logic next to that.
Method 2:
Create MySimpleCursorAdapter which extends SimpleCursorAdapter, overwrite getView method and wrote logic there.
Now I'm working with the second method. Can anyone suggest me which is the best method or if there any other best methods.
If, depending on the value of the column is necessary to make many changes over the item in the list, the second method is more convenient.
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.
I'm now developing an application that uses a ListView with a
CheckedTextView on every item that managed by an ArrayAdapter to
support multiple chooses. The contents in my ListView are dynamic, that
means, can be changed during runtime. Now I try to use
ListView.getCheckedItemPositions() to get all checked items, Because I want
to save all the checked positions and auto-check them when user go back to
this page again. So I need to save checked results for every page.
For the first page everything works fine as expected. But when user goes to
another page and make some chooses, the result array that ListView returned
contains some positions that are never checked. I don't why ListView has
this strange behavior. Even for a page that in fact no checked happens but
ListView gives me a result that indicates there's one item has been checked.
could anyone who can teach me how to get the position of CheckedTextView
in its OnClickListener callback?
example code is appreciate.
Thanks in advance...
The listview recycles its views so when you go to a different page and then return to the previous page, the listview recalls the getView() function for its views. To make sure that the order of the checked views are not mixed up, create an arraylist that contains the check state of all the views before initializing the adapter. Then pass the arraylist as an argument for the adapter's constructor. There, in the getView() function, set the checked state of each checkable textview based on the arraylist. Then, return to the activity class and override the onItemClick() event. Using the view that is given to you when the function is called, do the following to get the checkable textview and set its checked state:
listView1.setOnItemClickListener(new OnItemClickListener()
{
#Override
public void onItemClick(AdapterView<?> arg0, View selectedView, int position , long id)
{
CheckedTextView tv = (CheckedTextView)selectedView.findViewById(R.id.textview);
if (tv.isChecked())
{
tv.setChecked(false);
checkStatesOfViews.get(position) = false;
}
else
{
tv.setChecked(true);
checkStatesOfViews.get(position) = true;
}
}
});
As the title, how can I remove the filtering on an ArrayAdapter used by an AutoCompleteTextView to get the original list back?
A little more background:
It all started from the sad fact that the "position" value passed in to onItemClick() is useless. The "position" refers to the position AFTER the array has been filtered, but I need to know its REAL position. So, what I'm trying to do is when I've got the text of the selected item (by using getItemAtPosition(position)), I compare it one-by-one with the original string array that backs the ArrayAdapter. However, I found that when onItemClick() is called, the adapter is already filtered, I no longer have access to the original array. So I thought if I can remove the filter, maybe I can get back the original array and look for the selected item in it.
ArrayAdapter<String> mAdapter;
public void onCreate() {
// Create an adapter and remembere it as a class member.
mAdapter = new ArrayAdapter<String>(this, layoutId);
// Add 100 strings to it and attach it to an AutoCompleteTextView
for (int i = 0; i < 100; i++)
mAdapter.add("random text");
((AutoCompleteTextView)findViewById(id)).setAdapter(mAdapter);
}
#Override
public void onItemClick(AdapterView<?> actv, View view, int position, long id) {
if (actv.getAdapter().equals(mAdapter))
Log.d("The adapter contained in actv is the same one I created earlier.");
// And, I can get the text of the item the user selected
String selected = (String)actv.getItemAtPosition(position);
// However, although the adapter passed in is still the same one, but the
// number of items in it is only 1! Because the array has been filtered.
int numItems = actv.getAdapter.getCount();
// So, I'm thinking if I can somehow remove the filtering here, then I can
// get back those 100 items, and do a search like following:
for (int i = 0; i < actv.getAdapter.getCount(); i++)
if (selected == actv.getAdapter.getItem(i))
break; // Eureka!!!
}
To tackle the problem of obtaining the REAL position of the selected item:
Is there a way to utilize the "id" value? Like, assign each item an id, then hopefully onItemClick() would pass back the correct id.
Like I said above, remove the filter (is it possible), get back the original 100 items, and perform a one-by-one search.
This is the last resort, I know it'll work, but I don't want to do it: Once I get the text of the selected text, I go back to the source of the data (from a database), query those 100 items out, and perform the search.
Another lame last resort: To avoid the overhead on accessing the database again as in #3, when in onCreate(), while creating the ArrayAdapter, I use an ArrayList of my own to remember all those 100 strings.
Am I doing it all wrong? What's the "right" way of obtaining the real position of the selected item from an AutoCompleteTextView?
Thank you very much!
(I read somewhere, some buy that seemed to be from Google Android team, said that one should use getFirstVisiblePosition() to resolve the position. But I can't figure out how.)
I don't know if you're still interested, but I found this answering a similar question: Problem with AutoCompleteTextView and Spinner using the same Adapter
Copying the method in the AutoCompleteTextView source code:
Filter filter = mAdapter.getFilter();
filter = null;
See my response in the above question for the grepcode link.
This is actually pretty simple to solve.. Instead of adding each element to the adapter as you get it (I'm assuming your random text part is just for example purposes), instead use the following:
First build your array into a variable, call it myArray..
then initialize your adapter like this:
mAdapter = new ArrayAdapter<String>(this, layoutId, myArray);
Now make sure that myArray is a class variable so you can reference it from anywhere else in the class.. Of course if you need access to this from another class you'd want to make a getter for it... Then you can easily iterate over the array to see if the value selected is in the array.. You'll have the whole set of data there instead of trying to get it from the adapter.
Here is a good example on using a validator for a similar looking use case:
Android, Autocomplettextview, force text to be from the entry list
In my case, I have address that can be set either by autocomplete or clicking on the map. If user click on the map, editText text should be set to address selected from the map, and in that case filtering should be disable temporarily.
I code like this:
public void OnAddressFound(String address) {
// Temporary disable autocomplete
editTextSearch.setAdapter(null);
editTextSearch.setText(address);
// Enable autocomplete again
setAutoCompleteAdapter();
}
where setAutoCompleteAdapter() is called during onCreate, and again in temporary disable/enable filter:
void setAutoCompleteAdapter() {
PlacesAutoCompleteAdapter adapter = new PlacesAutoCompleteAdapter(this, R.layout.item_autocomplete_map_search, autoCompleteList);
editTextSearch.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
Hope its help you also.
I found the solution, kinnda tricky but its works
after i looking inside of the source, i found that th treshold variable used as filtering validation, here we just need to set the treshold to maximum int so filtering never perform.
threshold = Integer.MAX_VALUE
or
setThreshold(Integer.MAX_VALUE)