I have got a custom list view adapter and an image button in the adapter class. When i click on the image button, the listener should reload the list view. I need to reload the list view within getview() of adapter class. So I need to know other options than using notifyDataSetChanged() in my listActivity class.
Thanks
You want to refresh a cell inside the listview or do you want to refresh the whole listview, if a single row is loaded inside getView() ?
Check this out:
Android ListView Refresh Single Row
Create a static handler inside the activity which calls a method which reloads the listview and send a message to this handler from the adapter whenever required.
handler = new Handler() {
public void handleMessage(Message paramAnonymousMessage) {
switch (paramAnonymousMessage.what) {
case 1:
populateList();
break;
}
}
};
public void populateBill() {
MyBasketAdapter adapter = new MyBasketAdapter(this, basketList);
listView = (ListView) findViewById(android.R.id.list);
listView.setAdapter(adapter);
}
Inside the adapter class. for example,
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Message msg = Message.obtain();
msg.what = 1;
MyActivity.handler.sendMessage(msg);
}
});
That is very Simple just write a method in your adapter class and call it get view when you deleting or adding anything in your list which you are binding to your adapter.and use notifyDataSetChanged after change in list
public void updateResults(ArrayList<CustomList> results) {
// assign the new result list to your existing list it will work
notifyDataSetChanged();
}
Related
i've created a custom list with four textviews...the data in this list is saved through a dialog which has a ok button. when i add the data, it gets saved in the list(works fine till now). when i add the next element, all the rows gets same value as the last one...the notifyDatasetChanged() is also not working...am i wrong somewhere?...this is my code...
ok.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String val = editquantity.getText().toString();
valq1 = Integer.parseInt(val);
ListView l;
l = (ListView) v.findViewById(R.id.order_listview);
myAdapter adapter = new myAdapter(getActivity(), row);
l.setAdapter(adapter);
row.add("");
adapter.notifyDataSetChanged();
builder.dismiss();
}
});
builder.setView(dialog);
builder.show();
You created new adapter everytime you click ok. Put your adapter code outside the onclick method:
ListView l = (ListView) v.findViewById(R.id.order_listview);
myAdapter adapter = new myAdapter(getActivity(), row);
l.setAdapter(adapter);
ok.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String val = editquantity.getText().toString();
valq1 = Integer.parseInt(val);
row.add(""); //add new item to the list
adapter.notifyDataSetChanged(); //notify adapter
builder.dismiss();
}
});
builder.setView(dialog);
builder.show();
You need to use addAll() method for adding new values remaining old values are same in arraylist.
row.addAll("test");
Why are you adding row as blank.
Secondly you have set row in adapter without defining it.
Please provide more details to the question as i cannot understand where row has been declared.
Coming to the similar value problem.
You need to update row array because it has been set on adapter.
There are three things you need to change
1. Declare your ListView object outside of the onCreate()
2. Declare your adapter object outside of the onCreate()
Now this initialization of this below line needs to be initialized only once in onCreate(). You need not to initialize it again and again when you add new item.So below line write in your onCreate().
myAdapter adapter = new myAdapter(getActivity(), row);
When you add new item you only need to add that item in your arraylist named row onClick of ok button and then call adapter.notifyDataSetChanged(); it will work fine.
i am using a recyclerView and loading the data from database.The recyclerView item have 2 buttons. The recyclerView loads fine and clicks work fine for the following code.
allData=db.getCatData(CATEGORYLIST_CIDD,1);
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
later i rearrange the adapter data for displaying the data in descending order by using this code
db=new DatabaseHandler(getActivity().getApplicationContext());
allData=db.getCatData(CATEGORYLIST_CIDD,order_id);
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
textlistadapter.notifyDataSetChanged();
Now the items are rearranged on the recyclerView, but the onShareButtonClickListener returns null, here is the code of the adapter.
private OnShareButtonClickListener onShareButtonClickListener;
public interface OnShareButtonClickListener {
void onItemClick(View view, Pojo obj, int position);
}
public void setOnShareButtonClickListener(final OnShareButtonClickListener onShareButtonClickListener) {
this.onShareButtonClickListener = onShareButtonClickListener;
}
the click listener code is here
holder.bt_share.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//Snackbar.make(view, "Share Clicked", Snackbar.LENGTH_SHORT).show();
if (onShareButtonClickListener != null) {
onShareButtonClickListener.onItemClick(view, c, position);
}
}
});
The click does not work since the onShareButtonClickListener is null.
The same code works well for the first time and once i change the order then the click events are not working, all other functions are working well.
you should only need to do this once:
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
later on, if you want to update/change the data, then you should do something like this:
textlistadapter.setListItems(allData);
textlistadapter.notifyDataSetChanged();
Where setListItems() is a public method in your adapter, an example like this:
public void setListItems(List<> allData) {
this.data.clear();
this.data.addAll(allData);
}
It's easy to understand what you are doing wrong. You populate an array which will feed your adapter with data, that meaning that, after setting the adapter, if you want it's data to change, you only need to change the array you populated the data with, and notify the adapter for the data change.
For example:
myData = db.getData();
myAdapter = new MyAdapter(this,myData);
recyvlerview.setAdapter(myAdapter);
Now every time you want to change the data, you only need to change your myData and notifity the adapter
myAdapter.notifyDataSetChange();
Basically instead of doing this:
db=new DatabaseHandler(getActivity().getApplicationContext());
allData=db.getCatData(CATEGORYLIST_CIDD,order_id);
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
textlistadapter.notifyDataSetChanged();
This should suffice
db=new DatabaseHandler(getActivity().getApplicationContext());
allData=db.getCatData(CATEGORYLIST_CIDD,order_id);
textlistadapter.notifyDataSetChanged();
I have Mainactivity which contain listview with some item and I want to add another listview in that listview as footer.How can I add this
Its not recommended to add a ListView as a footer of another ListView. You might consider making a list of objects containing both list and pass the list to your Adapter.
So if you merge two lists in a common format, you need to be tricky for the layout selection for each item in your list. Let me show you an example of a common class.
public class CommonClass {
// Set null values initially.
private ClassA mFirstListClass = null;
private ClassB mSecondListClass = null;
}
Now take an ArrayList of this object to pass it to your Adapter. In your bindView check if the item is a ClassA object or ClassB object (as you can easily determine them by checking which object is null) and then set proper action.
I think for these kinds of problems RecyclerView is better. Its very simple to implement and you can find the implementation document here.
// Create a List from String Array elements
final List<String> tests = new ArrayList<String>(Arrays.asList(test));
// Create an ArrayAdapter from List
final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>
(this, android.R.layout.simple_list_item_1, tests);
// DataBind ListView with items from ArrayAdapter
lv.setAdapter(arrayAdapter);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Add new Items to List
tests.add("abc");
tests.add("def");
/*
notifyDataSetChanged ()
Notifies the attached observers that the underlying
data has been changed and any View reflecting the
data set should refresh itself.
*/
arrayAdapter.notifyDataSetChanged();
}
});
for more http://android--code.blogspot.in/2015/08/android-listview-add-items.html
I am trying to set up a gridview that will refresh when a new search is executed.
this is my call to set up the gridview
final GridElement_Results adapter = new GridElement_Results(this, savedInstanceState, track_name, album_name, track_num, album_id, album_link);
grid = (GridView)findViewById(R.id.grid_results);
grid.setAdapter(adapter);
As you can see, I am passing it a bunch of arrays.
On a button click, the function getTracks() is called which gets new data from the server. The arrays are updated with the new data, which I have verified is working.
icon_activesearch.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
getTracks("newsearchterm");
adapter.notifyDataSetChanged();
grid.invalidateViews();
}
}
);
And then I call adapter.notifyDataSetChanged() and grid.invalidateViews() to update and redraw the grid. But obviously I'm doing something wrong here.
Is it because I'm setting the adapter as final? To access it within the onClick method I need to set it to final.
What should I change to get it to work.
you should wait until new data fetch then notify adapter but you call notify just after getTracks() without any delay
I have an android activity that consists of a List View and a Text View. The Text view displays information about the summed contents of the list view, if the items in the list view are updated then the Text View needs to reflect the change.
Sort of like an observer pattern but with one component reflecting the changes of many rather than the other way round.
The tasks are displayed as items in the list view and the progress can be updated using a seekbar to set the new progress level.
The following method populates the TextView so I need to call this again from inside the SeekBar onStopTrackingProgress Listener.
private void populateOverviewText() {
TextView overview = (TextView) findViewById(R.id.TaskOverview);
if (!taskArrayList.isEmpty()) {
int completion = 0;
try {
completion = taskHandler.getProjectCompletion();
overview.setText("Project Completion = " + completion);
} catch (ProjectManagementException e) {
Log.d("Exception getting Tasks List from project",
e.getMessage());
}
}
}
I realise if I want to call the method from the List Adapter then I'll need to make the method accessible but I'm not sure the best approach to do this.
Either make this method public
or you can pass activity to adapter through which you can find the button and update text, or can directly pass Button to adapter...
Using DataSetObserver
I was looking for a solution that didn't involve altering the adapter code, so the adapter could be reused in other situations.
I acheived this using a DataSetObserver
The code for creating the Observer is incredibly straight forward, I simply add a call to the method which updates the TextView inside the onChanged() method.
Attaching the Observer (Added to Activity displaying list)
final TaskAdapter taskAdapter = new TaskAdapter(this, R.id.list, taskArrayList);
/* Observer */
final DataSetObserver observer = new DataSetObserver() {
#Override
public void onChanged() {
populateOverviewText();
}
};
taskAdapter.registerDataSetObserver(observer);
Firing the OnChanged Method (Added to the SeekBar Listener inside the adapter)
public void onStopTrackingTouch(SeekBar seekBar) {
int progress = seekBar.getProgress();
int task_id = (Integer) seekBar.getTag();
TaskHandler taskHandler = new TaskHandler(DBAdapter
.getDBAdapterInstance(getContext()));
taskHandler.updateTaskProgress(task_id, progress);
mList.get(position).setProgress(progress);
//need to fire an update to the activity
notifyDataSetChanged();
}