I am working with an adapter which has several buttons on each item of the ListView. I have, for example two buttons. One for save and another for delete.
When I click on them, I want the adapter to refresh. I have a method on my activity that does that: Update the adapter. I made it since I couldn't make the Notify methods of the adapter work.
I am sending the Activity to the adapter as a parameter and then call the update method from the adapter since I am setting the OnClick methods of each button in the adapter.
The problem is that it doesnt seem to work always. I am guessing it has to do something about the cycle of the activity and Android cleaning memory however I can't seem to understand where is the problem.
I am aware this is some ugly way of doing it, so what should be the best way of doing this?
Summary: I need to refresh the adapter from the adapter itself when I delete an item of the ListView or update it (BaseAdapter)
Edit:
I am adding some code. This is my constructor of my adapter:
public SpendingPlanAdapter(Context context, SpendingPlan sp, int month, int year, money.activities.SpendingPlan act)
Inside the adapter I have an OnCLickListener attached to a button. I am calling the update method like this (Result is the result of a database insert):
if (result){
Toast.makeText(context, context.getResources().getString(R.string.succesfully_deleted), Toast.LENGTH_LONG).show();
act.updateAdapter();
} else {
Toast.makeText(context, context.getResources().getString(R.string.oops), Toast.LENGTH_LONG).show();}
And this is my UpdateAdapter method:
public void updateAdapter(){
SpendingPlanAdapter adapter = new SpendingPlanAdapter(getApplicationContext(), currentSp, currentMonth, currentYear, this);
limitList.setAdapter(adapter);
}
You can call updateAdapter() like this
(SpendingPlan (context)).updateAdapter();
Related
I have two listview, like listview_1 and listview_2. I wanna refresh the listview_2 while listview_1 is refreshed.
My code like this:
public void updateTwoListView() {
listview_1.getAdapter().notifyDataSetChanged();
listview_2.getAdapter().notifyDataSetChanged();
}
But it don't work, listview_1 can refresh but the listview_2 can't.
And at that moment what I found is that listview_1 was on focus.
And then I tried to set focus to other views before ran the method, both of them didn't refresh. It likes to refresh a listview only if the listview has focus.
What's more I found that when I called the method to refresh, listview_2 didn't, and then I set focus to listview_2, refreshed itself!
So, What all I want to ask is:
How to refresh two listview at one moment in Android?
What's more code:
//init two listview there
public void init() {
listview_1 = (ListView)findViewById(R.id.listView1);
listview_2 = (ListView)findViewById(R.id.listView2);
adapter1 = new MyListViewAdapter(mContext);
adapter2 = new MyListViewAdapter(mContext); //I have tried use different adapter, that also didn't work.
listview_1.setAdapter(adapter1);
listView_2.setAdapter(adapter2);
}
the real code of upside snippet is:
public void updateTwoListView(int currentPosition) {
adapter1.updateCurPos(currentPosition);
adapter2.updateCurPos(currentPosition);
}
and in MyListViewAdapter.java:
public void updateCurPos(int currentPosition) {
mCurrentPos = currentPosition;
notifyDataSetChanged();
}
And I will call method like listViewManager.updateTwoListView(1) outside to refresh.
Any reply is appreciated.
You have called listview_1 twice. Just change one of them to listview_2 as below:
public void updateTwoListView() {
listview_1.getAdapter().notifyDataSetChanged();
listview_2.getAdapter().notifyDataSetChanged();
}
It seems the problem of your code is that you call getAdapter().
Sets the data behind this ListView. The adapter passed to this method may be wrapped by a WrapperListAdapter, depending on the ListView features currently in use. For instance, adding headers and/or footers will cause the adapter to be wrapped.
Source: http://developer.android.com/reference/android/widget/ListView.html#setAdapter(android.widget.ListAdapter)
The solution is save your Adapter as member variable in your activity and call the notifyDataSetChanged()from there.
See more on this question's answer: https://stackoverflow.com/a/31893525/2742759
Here's my code so far, but the application crashes when I press the update button.
I want to update a selected item in my list, I have already created the update activity that will allow me to load the values on my database but I can't figure out how to load the value of selected item in list.
{
ArrayAdapter<String> ard=new ArrayAdapter<String> (this,android.R.layout.simple_list_item_single_choice,list);
lv.setAdapter(ard);
lv.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
btnupdate.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
SparseBooleanArray sba = lv.getCheckedItemPositions();
Intent intent = new Intent(HomeworkInfo.this, UpdateHomework.class);
startActivity(intent);
finish();
}
});
}
When an ArrayAdapter is constructed, it holds the reference for the List that was passed in. If you were to pass in a List that was a member of an Activity, and change that Activity member later, the ArrayAdapter is still holding a reference to the original List. The Adapter does not know you changed the List in the Activity.
Your choices are:
Use the functions of the ArrayAdapter to modify the underlying List (add(), insert(), remove(), clear(), etc.)
Re-create the ArrayAdapter with the new List data. (Uses a lot of resources and garbage collection.)
Create your own class derived from BaseAdapter and ListAdapter that allows changing of the underlying List data structure.
Use the notifyDataSetChanged() every time the list is updated. To call it on the UI-Thread, use the runOnUiThread() of Activity. Then, notifyDataSetChanged() will work.
I hope this helps you ..
Happy coding !!
In my OncreateView() set the adapter which is working when i am first loading the page. When i go to another page and make changes then come back to this fragment it is not working adapter.notifyDatasetchanged().
#Override
public void onStart() {
super.onStart();
groupItem.clear();
childItem.clear();
List<String> child_Category;child_Category=new ArrayList<String>();
groupItem = obj_Listdatabase.fetchcategory();
childItem.clear();
ListIterator<String> iterator = groupItem
.listIterator();
while (iterator.hasNext()) {
String categoryname = iterator.next();
child_Category = new ArrayList<String>();
child_Category = obj_Listdatabase
.fetchchildlist(categoryname);
childItem.add(child_Category);
}
adapter.notifyDataSetChanged();
}
Hai I got output for this one:
groupItem.addAll(obj_Listdatabase.fetchcategory());
Instead of This
//groupItem = obj_Listdatabase.fetchcategory();
Because i change the reference in assignment statement(=) for that adapter.So i use addAll() method to store the values only instead of reference.
You should reaaaally indent your code more cleanly, never use several ";" on the same line for example.
And you can definitely use BaseExpandableListAdapter the issu is somewhere else..
You should also notice that onCreate view is more suitable for "creating view" so all the adapter stuff should be somewhere else like onViewCreated, or onActivityCreated as you need (it's just some advices)
I assume your adapter is in a Fragment since you use GetActivity() and in the constructor of your adapter you pass a reference to the activity (context), the group list and the child list.. ok
we ll assume that you are using the fragment onStart. From the official doc :
Called when the Fragment is visible to the user. This is generally tied to Activity.onStart of the containing Activity's lifecycle.
So normally this method is called after onViewCreate, onViewCreated .. etc at least the first time you code is running. So this is ok
Did you try using adapter.notifyDataSetInvalidate() and then do adapter.notidyDataSetChanged ?
One last thing, since you actually pass the data to your adapter by the constructor, when you update your lists how can the adapter be aware of the changes ? Are your lists global (static) ?
If not, before doing adapter.notifyDataSetChanged() you should pass the lists (group and child) to the adapter with some setter..
good luck
I'm having a strange issue with a custom implementation of Android's ArrayAdapter. To give some background, I'm trying update a ListView's contents while preserving the current scroll position.
I have a service which executes a thread to update data that's displayed in the ListView. That data is stored in an ArrayList and that ArrayList is used to generate some custom ArrayAdapters for the ListView. The adapters are also updated when an item in the ListView is pressed (either adding or removing an item). I used to just create new adapters each time there was any type of change and then set this new adapter to the ListView. This worked, but caused the ListView to scroll to the top each time. Given the nature of my application this was undesirable. The current scrolled position in the ListView must be maintained between updates.
Instead of creating new adapters I began clearing the adapter that I needed to update using the adapter's clear() method, then rebuild the adapter's items by using the adapter's add() method. Both of these methods are being called on the adapter. The adapters are all set to notifyDataOnChange in their constructors so I don't have to manually call notiftyDatasetChanged() each time (although given my issue I've tried calling it manually as well to no avail).
Here's what my custom adapter looks like:
public class RealmAdapter extends ArrayAdapter<Realm>
{
Context c;
public RealmAdapter(Context context, int resource, int textViewResourceId)
{
super(context, resource, textViewResourceId);
setNotifyOnChange(true);
c = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
...
}
...
}
Long story short, here's my issue. When I call clear() on the adapter, the adapter is not being cleared.
Here's a snippet from my onPostExecute in my thread that does updating. I'm being sure to put it here so it's updating on the UI thread. I also have this exact code copied in a private method in my UI activity. This code does not work in either place:
appState.favoriteAdapter.clear();
Log.d(LOG_TAG, "COUNT: " + appState.favoriteAdapter.getCount());
for(Realm r : appState.favorites) {
appState.favoriteAdapter.add(r);
}
Log.d(LOG_TAG, "COUNT: " + appState.favoriteAdapter.getCount());
As an example, if the above adapter had 3 items in it, calling a getCount() right after the clear() is returning 3 instead of 0. Likewise, if the appState.favorites ArrayList only has 2 items in it, the getCount() after the loop is still returning 3, not 2. Because the adapter is not responding to any of these calls it makes it impossible to update in any fashion. I can post a Logcat later if that will be helpful, but there are no exceptions or anything useful being displayed.
After busting my head for hours, the issue I appear to be having is that the adapter is not responding to calls to any methods that alter it. I've tried passing an empty ArrayList into the adapter's super() call, this does not help. Am I missing something or using the ArrayAdapter incorrectly? I've searched all over and I've already checked a lot of the common problems such as modifying the underlying array and expecting it to update, not calling (or in my casing setting to the adapter) notifyDatasetChanged(), and using an unsupported operation on the underlying collection.
The declaration of the favoriteAdapter is very simple and is contained in my Application class:
public RealmAdapter favoriteAdapter;
Here is the initialization of the favoriteAdapter from above:
if(appState.favoriteAdapter == null) {
appState.favoriteAdapter = new RealmAdapter(c, R.layout.list_item, R.layout.realm_entry, appState.favorites);
}
else {
appState.favoriteAdapter.clear();
Log.d(LOG_TAG, "COUNT: " + appState.favoriteAdapter.getCount());
for(Realm r : appState.favorites) {
appState.favoriteAdapter.add(r);
}
Log.d(LOG_TAG, "COUNT: " + appState.favoriteAdapter.getCount());
}
The above code is in both my UI thread and the thread that downloads the refreshed data.
Underneath the code above a filter is put in place:
if(appState.favoriteAdapter != null && RealmSelector.realmFilter != null) appState.favoriteAdapter.getFilter().filter(RealmSelector.realmFilter.getText().toString());
Would the filter affect clearing the list? Logic would dictate not...
I had filters being applied to the custom ArrayAdapter. Apparently this interferes with adding and removing items from the adapter itself? I added this code to my method and it is now working:
if(appState.favoriteAdapter != null && realmFilter != null) {
appState.favoriteAdapter.getFilter().filter(realmFilter.getText().toString());
}
I'd love if anyone could explain why this matters. I thought filters were meant to select subsets of items in the adapter. In my testing I was leaving the text box that is used for the filter empty, thus no actual filter text should have been applied. Again, if someone knows what's going on and could explain to me why this fixes the problem I'd love to know.
I have this ListView that is using an array adapter:
//global
ArrayList<Location> locations=new ArrayList<Location>(); //array list of location objects
ArrayAdapter<Location> theLocations;
ListView listView;
then in onCreateView of my Fragment:
theLocations = new ArrayAdapter<Location>(mContext,
R.layout.location_row, locations);
listView.setAdapter(theLocations);
This works pretty well I think, though if I try to update this adapter it freaks out...
//in my fragment, another dialog makes this call here to update the list.
public void onUIUpdate(Location l) { //listener call back when dialog "ok" clicked
locations.add(l); //it is okay with this.
theLocations.notifyDataSetChanged(); //dies
}
It dies with the error:
07-23 08:03:28.655: ERROR/AndroidRuntime(509): java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView
does that mean it doesn't like the Location in the ArrayAdapter ??? does this mean I have to make my own custom listadapter? If I don't call theLocations.notifyDataSetChanged() everything is okay but then nothing updates... :(
I should note that the toString() in the Location class is override to return a String name;
after a comment I tried this:
public void onUIUpdate(Location l) {
locations.add(l);
//theLocations.notifyDataSetChanged();
WrapperListAdapter wr = (WrapperListAdapter)listView.getAdapter();
ArrayAdapter aa=(ArrayAdapter)wr.getWrappedAdapter();
aa.notifyDataSetChanged();
}
LOL no luck here, was a stab in the dark. Also wandering if its the addHeaderView I used on the ListView? I am not sure if it makes it immutable in the future using addHeaderView?
I won't comment about ListView design, it is very ugly, but I do listView.getAdapter().getWrappedAdapter().notifyDataSetChabged(); and it works.