I found many similar questions on StackOverflow, but can't seem to figure out this issue.
I'm trying to bind an ObservableCollection to a ListView so that when the contents of the collection change the ListView will automatically update. Unfortunately, when elements are added to the collection (via button click), the ListView isn't being updated. How can I make the ListView reflect the current contents of the collection?
Note: It seems that if I force layout with listView.RequestLayout(); the listView will contain the correct number of items. However, it won't necessarily contain the right items. For example, if I delete the first item and add a new one at the end, forcing a layout has no effect. If I force the layout after deleting the first item, then again after adding one at the end, the contents are correct.
Activity code
public class MainActivity : Activity
{
int count = 1;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
ObservableCollection<UserTask> allTasksCollection = new ObservableCollection<UserTask>();
while(count < 6)
{
allTasksCollection.Add(new UserTask("Task number " + count));
count++;
}
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
// Bind listview to all tasks
ListView listView = FindViewById<ListView>(Resource.Id.allTasksListView);
UserTaskListAdapter adapter = new UserTaskListAdapter(this, allTasksCollection);
listView.Adapter = adapter;
// Button click should add a new task and remove the first task.
Button button = FindViewById<Button>(Resource.Id.myButton);
button.Click += delegate {
allTasksCollection.Add(new UserTask("Task number " + count));
button.Text = string.Format("{0} tasks!", count++);
};
}
}
Adapter
public class UserTaskListAdapter : BaseAdapter<UserTask>
{
Activity context;
ObservableCollection<UserTask> list;
public UserTaskListAdapter(Activity _context, ObservableCollection<UserTask> _list)
: base()
{
this.context = _context;
this.list = _list;
}
public override int Count
{
get { return list.Count; }
}
public override long GetItemId(int position)
{
return position;
}
public override UserTask this[int index]
{
get { return list[index]; }
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
View view = convertView;
if (view == null)
view = context.LayoutInflater.Inflate(Resource.Layout.UserTaskRowItem, parent, false);
UserTask item = this[position];
view.FindViewById<TextView>(Resource.Id.Title).Text = item.Name;
return view;
}
}
Main XAML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/rootLayout">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/allTasksContainer">
<Button
android:id="#+id/myButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/hello" />
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/allTasksListView" />
</LinearLayout>
</LinearLayout>
ListItem XAML
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/linearLayoutHorizontal">
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/CheckboxContainer">
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/checkboxSelect" />
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/TextContainer">
<TextView
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/Title" />
<TextView
android:text="Small Text"
android:textAppearance="?android:attr/textAppearanceSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/DueDate" />
</LinearLayout>
</LinearLayout>
</RelativeLayout>
Try to call NotifyDataSetChanged() on your adapter after updating its items, AFAIK ListView in Android doesn't observe the changes on your ObservableCollection:
Try this code:
button.Click += delegate {
allTasksCollection.Add(new UserTask("Task number " + count));
button.Text = string.Format("{0} tasks!", count++);
adapter.NotifyDataSetChanged();
};
You can also try to add a litener to your ObservableCollection, in your adapter, change the constructor to this:
this.list.CollectionChanged += (sender,args) => { NotifyDataSetChanged(); };
Take a look at the INotifyPropertyChanged interface. It will warn the listview that variables within an object within the listview have changed.
https://developer.xamarin.com/guides/xamarin-forms/xaml/xaml-basics/data_bindings_to_mvvm/
Edit: misread your question. My bad.
Related
I have a ListView in one of my activities that I have bound to an ArrayList using a custom ArrayAdapter. I have set an OnItemClickListener to the ListView which should call a method that starts another activity. However, I find that when I click on the ListView items, it only sometimes works. Sometimes it will start the activity as it should; other times it seems to detect the click (the ripple effect appears on the list item) but does nothing; other times it doesn't even appear to detect the click (the ripple effect doesn't appear).
I've tried all the usual suggestions that I've come across: blocking descendants on the parent view item, setting clickable and focusable to false on all the components of the item views, setting isEnabled to return true in the custom adapter, etc, but the behavior remains the same. Any help appreciated. Here is the relevant code:
Activity containing the ListView:
public class ViewCollectionActivity extends AppCompatActivity {
private final String className = this.getClass().getSimpleName();
private CollectionHandler collectionHandler;
private Context context;
private ArrayList<Game> displayedCollection;
private GameCollectionAdapter collectionAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_collection);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
context = this;
collectionHandler = CollectionHandler.getInstance(this);
TextView view = null;
if (collectionHandler.getDisplayedCollection().size() > 0) {
view = (TextView) findViewById(R.id.no_items_textview);
view.setVisibility(View.GONE);
}
String currentDate = collectionHandler.getDateLastSynchronised();
view = (TextView) findViewById(R.id.last_updated_textview);
view.setText("Last synchronised: " + currentDate + " Total games: " + String.valueOf(collectionHandler.getDisplayedCollection().size()));
collectionAdapter = collectionHandler.getCollectionAdapter();
ListView listView = (ListView) findViewById(R.id.collection_list_view);
listView.setAdapter(collectionAdapter);
AdapterView.OnItemClickListener collectionItemClickListener = new AdapterView.OnItemClickListener(){
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
launchGameDetailsActivity(position);
}
};
listView.setOnItemClickListener(collectionItemClickListener);
}
public void launchGameDetailsActivity(int position){
Log.d(className,"Starting lauchGameDetailsActivity method");
collectionHandler.setSelectedGame(position);
Intent intent = new Intent(this,ViewGameDetailsActivity.class);
startActivity(intent);
Log.d(className, "Ending lauchGameDetailsActivity method");
}
The XML for the activity:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.bleachedlizard.ludome.viewcollection.ViewCollectionActivity">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Synchronise Collection"
android:onClick="synchroniseCollection"/>
<TextView
android:id="#+id/last_updated_textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Last synchronised: "
android:textAlignment="center"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Display Collection"
android:visibility="gone"
android:onClick="displayCollection"/>
<ListView
android:id="#+id/collection_list_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
</ListView>
<TextView
android:id="#+id/no_items_textview"
android:layout_width="match_parent"
android:layout_height="50dp"
android:text="You have no items in your collection."
android:textAlignment="center"
android:textSize="20sp"/>
</LinearLayout>
The XML for the item views:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/collection_item_layout"
android:layout_width="match_parent"
android:layout_height="75dp"
android:orientation="horizontal"
android:clickable="false"
android:descendantFocusability="blocksDescendants"
android:focusable="false"
android:focusableInTouchMode="false">
<ImageView
android:id="#+id/collection_item_image"
android:layout_width="75dp"
android:layout_height="75dp"
android:src="#drawable/testimage"
android:focusable="false"
android:focusableInTouchMode="false"
android:clickable="false"
/>
<TextView
android:id="#+id/collection_item_name"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="center_vertical"
android:padding="16dp"
android:singleLine="false"
android:textColor="#android:color/darker_gray"
android:focusable="false"
android:focusableInTouchMode="false"
android:clickable="false"
android:textIsSelectable="false"/>
<TextView
android:id="#+id/collection_item_plays"
android:layout_width="100dp"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:padding="8dp"
android:textColor="#android:color/darker_gray"
android:text="Plays: 0"
android:focusable="false"
android:focusableInTouchMode="false"
android:clickable="false"
android:textIsSelectable="false"/>
</LinearLayout>
The code for the custom adapter:
public class GameCollectionAdapter extends ArrayAdapter<Game> {
private ArrayList<Game> collection;
public GameCollectionAdapter(Context context, int resource, ArrayList<Game> collection){
super(context, resource, collection);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout gameView = (LinearLayout) convertView;
LayoutInflater mInflater = LayoutInflater.from(getContext());
if (gameView == null) {
gameView = (LinearLayout) mInflater.inflate(R.layout.collection_item_view, null);
}
//Game game = collection.get(position);
Game game = super.getItem(position);
if (game != null) {
// This is how you obtain a reference to the TextViews.
// These TextViews are created in the XML files we defined.
TextView gameTitle = (TextView) gameView.findViewById(R.id.collection_item_name);
TextView numOfPlays = (TextView) gameView.findViewById(R.id.collection_item_plays);
ImageView thumbnail = (ImageView) gameView.findViewById(R.id.collection_item_image);
// check to see if each individual textview is null.
// if not, assign some text!
if (gameTitle != null){
gameTitle.setText(game.getTitle());
}
if (numOfPlays != null){
numOfPlays.setText("Plays: " + String.valueOf(game.getNumOfPlays()));
}
if (thumbnail != null){
thumbnail.setImageBitmap(game.getThumbnail());
}
}
// the view must be returned to our activity
return gameView;
}
#Override
public boolean isEnabled(int position) {
return true;
}
}
I discovered what was causing the problem: the way I had set up the array that backed the ListView meant that it was downloading and storing the Bitmaps for every element in the array all the time. Once I changed the implementation so that it only downloaded the images as the ListView required them, then that seemed to improve performance and the onClickListener started to work fine.
The implementation I used was the exact same one shown here:
http://developer.android.com/training/displaying-bitmaps/process-bitmap.html
I think the issue is due to the position of the item selection whenever you click you have an list position which is passed to your method launchGameDetailActivity(int position) check with log or toast on item click what all the position you are getting do the needful.
Here is my code try this like this if it helps.
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(RecipeClass.this, "Position is" + position, Toast.LENGTH_SHORT).show();
Intent intent = new Intent(RecipeClass.this, RecipeIngredients.class)
intent.putExtra("position", position);
startActivity(intent);
}
Check your arraylist value also whether they are not null.
Trying to create custom rows in my listview (to look like this). I've created a custom row layout & derived adapter class. The data loads and shows fine, but the text is not using any format/style specified in my custom row .xml layout file. It's all just the default size/weight, etc.
Here's the custom row layout (listview_desc.xml)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#222222">
<TextView
android:id="#+id/name"
android:text="Name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_margin="10dip"
android:textStyle="bold"
android:textSize="20dip"
/>
<TextView
android:id="#+id/description"
android:text="Description"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_margin="10dip"
android:textSize="13dip" />
</LinearLayout>
Here's my main layout file:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:theme="#android:style/Theme.NoTitleBar"
android:minWidth="25px"
android:minHeight="25px"
android:background="#drawable/gradient_darkbg">
<ListView
android:minWidth="25px"
android:minHeight="25px"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/listView1" />
</LinearLayout>
My adapter code (I'm using Xamarin, but I don't think that's the problem...)
public class ListViewFormAdapter : BaseAdapter<Form>
{
List<Form> mForms;
Activity context;
public ListViewFormAdapter(Activity context, List<Form> items)
: base()
{
this.context = context;
this.mForms = items;
}
public override long GetItemId(int position)
{
return position;
}
public override Form this[int position]
{
get { return mForms[position]; }
}
public override int Count
{
get { return mForms.Count; }
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var item = mForms[position];
View view = convertView;
if (view == null) // no view to re-use, create new
view = context.LayoutInflater.Inflate(Resource.Layout.listview_desc, null);
view.FindViewById<TextView>(Resource.Id.name).Text = item.Name;
view.FindViewById<TextView>(Resource.Id.description).Text = item.Description;
return view;
}
}
And finally the main activity where I load and use the adapter:
public class HomeScreenActivity : Activity
{
List<Form> mForms;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
// Create your application here
SetContentView (Resource.Layout.Home);
// Load all forms and populate the main menu
mForms = Utils.FormLoader.LoadForms("Forms");
ListView listView = FindViewById<ListView>(Resource.Id.listView1);
listView.Adapter = new ListViewFormAdapter(this, mForms);
}
}
Sorry for all the code, maybe it'll help someone in the future... thanks for any help.
I'm not sure that this is the problem, but you inflating the views incorrectly. it should be
view = inflater.inflate(R.layout.listview_desc, parent, false);
instead of
view = context.LayoutInflater.Inflate(Resource.Layout.listview_desc, null);
using the 3 parameter version of inflate
What styles aren't showing correctly? I'm not sure what you're expecting or what you're seeing from the question. If it is to do with alignment, you should bear in mind that android:layout_alignParentLeft="true" is not valid in a LinearLayout
Thanks for the response guys. Turns out it was some problem with Git/Xamarin. I committed my sources at another machine, came home, synced up and all my formatting in the row layout xml were gone. Who knows... maybe a cached version was being used or something. I actually had to use the code posted on this page to get it to work (since it was lost), so maybe someone can use this as example code. It works.
I have a Activity that displays a list of check boxes (Focus Areas) that can be assigned to an activity event in my application. However I want to be able to prevent the user form editing these values until a button is clicked to put the form into edit mode.
Can some one explain or provide code sample how I can implement this into my application?
This list is held in a ListView with a custom ArrayAdapter of a Type FocusArea a class I have created for my application.
The xml for the Activity is shown below:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" android:background="#drawable/horizontal_gradient_line_reverse">
<TextView
android:id="#+id/textViewCustomerNameNumber"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Customer Name & Number" android:layout_margin="5dp"/>
<ListView
android:id="#+id/listViewFocusAreas"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/relativeLayoutControls"
android:layout_alignParentLeft="true"
android:layout_below="#+id/textViewCustomerNameNumber"
android:layout_margin="5dp"
android:background="#drawable/myborder" >
</ListView>
<RelativeLayout
android:id="#+id/relativeLayoutControls"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true" >
<ImageView
android:id="#+id/imageViewCancelFocusAreaChanges"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:src="#drawable/ic_mini_undo" />
<ImageView
android:id="#+id/imageViewSaveFocusAreaChanges"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="#+id/imageViewCancelFocusAreaChanges"
android:src="#drawable/ic_mini_save" />
<ImageView
android:id="#+id/imageViewEditFocusArea"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="#+id/imageViewSaveFocusAreaChanges"
android:src="#drawable/ic_mini_edit" />
</RelativeLayout>
<ImageView
android:id="#+id/imageViewEditMode"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/textViewCustomerNameNumber"
android:layout_alignRight="#+id/listViewFocusAreas"
android:src="#drawable/edit16x16"
android:visibility="gone" />
</RelativeLayout>
The following is the xml for the focus area row:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<CheckBox
android:id="#+id/checkBoxFocusArea"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Focus Area" />
</LinearLayout>
The following is the code for the Custom ArrayAdapter:
public class FocusAreaAdapter extends ArrayAdapter<FocusArea> {
private ArrayList<FocusArea> focusAreas;
private Context context;
public FocusAreaAdapter(Context context, int textViewResourceId, ArrayList<FocusArea> focusAreas) {
super(context, textViewResourceId, focusAreas);
this.context = context;
this.focusAreas = focusAreas;
}
#Override
public View getView(final int position, View convertView, final ViewGroup parent) {
View v = convertView;
if(v == null) {
LayoutInflater vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.focus_area_menu_item, null);
}
FocusArea focusArea = focusAreas.get(position);
if(focusArea != null) {
CheckBox cbFocusArea = (CheckBox)v.findViewById(R.id.checkBoxFocusArea);
cbFocusArea.setText(focusArea.getFocusAreaCodeDescription());
if(focusArea.isFocusAreaCodeChecked() == 1) {
cbFocusArea.setChecked(true);
} else {
cbFocusArea.setChecked(false);
}
cbFocusArea.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
FocusArea focusArea = focusAreas.get(position);
if(focusArea.isFocusAreaCodeChecked() == 1) {
focusArea.setFocusAreaCodeChecked(0);
} else {
focusArea.setFocusAreaCodeChecked(1);
}
}
});
}
return v;
}
}
Finally I instanciate my custom array adapter with the following code:
private void assignFocusAreasToAdapter() {
// get reference to available responsibles list view control
lvFocusAreas.clearChoices();
// create an array adapter with the communications data array
activityFocusAreaAdapter = new FocusAreaAdapter(this, R.layout.focus_area_menu_item, activityFocusAreas);
// assign the my customers list control the array adapter
lvFocusAreas.setAdapter(activityFocusAreaAdapter);
activityFocusAreaAdapter.notifyDataSetChanged();
Log.i(TAG, "Available Activity Focus Areas Loaded");
}
Ok i found the solution to this problem for anyone who might have the same issue.
The XML for the Focus Area activity stays the same as posted above.
The XML for the Focus Area row item is modified accordingly:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:descendantFocusability="blocksDescendants" >
<CheckBox
android:id="#+id/checkBoxFocusArea"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Focus Area" />
</LinearLayout>
You can see that this now has the following line added android:descendantFocusability="blocksDescendants" This prevents the checkboxes onClickListener from firing which normally will block the ListViews OnItemClickedListener from firing.
The Custom Adapter code is modified to remove the checkboxes OnClickListener like so:
public class FocusAreaAdapter extends ArrayAdapter<FocusArea> {
private ArrayList<FocusArea> focusAreas;
private Context context;
public FocusAreaAdapter(Context context, int textViewResourceId, ArrayList<FocusArea> focusAreas) {
super(context, textViewResourceId, focusAreas);
this.context = context;
this.focusAreas = focusAreas;
}
#Override
public View getView(final int position, View convertView, final ViewGroup parent) {
View v = convertView;
if(v == null) {
LayoutInflater vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.focus_area_menu_item, null);
}
FocusArea focusArea = focusAreas.get(position);
if(focusArea != null) {
CheckBox cbFocusArea = (CheckBox)v.findViewById(R.id.checkBoxFocusArea);
cbFocusArea.setText(focusArea.getFocusAreaCodeDescription());
if(focusArea.isFocusAreaCodeChecked() == 1) {
cbFocusArea.setChecked(true);
} else {
cbFocusArea.setChecked(false);
}
cbFocusArea.setClickable(false);
}
return v;
}
}
The Custom Adapter is instanciated using the same code as posted in above but you must add an OnItemClickListener to the ListView and preform the check of the checkbox inside the OnItemClickListener click event like so:
lvFocusAreas = (ListView)findViewById(R.id.listViewFocusAreas);
lvFocusAreas.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> adapter, View view, int position, long id) {
if(editMode){
FocusArea focusArea = (FocusArea)lvFocusAreas.getItemAtPosition(position);
if(focusArea.isFocusAreaCodeChecked() == 0) {
focusArea.setFocusAreaCodeChecked(1);
} else {
focusArea.setFocusAreaCodeChecked(0);
}
activityFocusAreaAdapter.notifyDataSetChanged();
setControlsEnabled();
}
}
});
Hope this helps any one thats having the same problem. :D
i have a list in android. and it has 30 records currently.
but on my activity i am only showing 5 records... after 5 records it shows me a button
"Display All Data"
when i click on that button, then it should display all 30 records and update the activity List. Please tell me how can i update. like we do in AJAX in web technology. i hope u guys understand what i am trying to say?
Refresh the Activity without refreshing the whole activity. Please Reply Friends.
waiting for positive response.
You should just simply add the newly arrived items to your list of data (the already listed 5 items), and call notifyDatasetChanged() on your ListAdapter implementation.
Update
Here I share a sample activity which contains a list and a TextView at the bottom (inflated from stepping_list.xml), where the list initially contains 5 items, and at the bottom a button. When pressing the button, other 25 values get loaded into the list, and the button disappears.
For this we need the main layout, res/layout/stepping_list.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="wrap_content">
<TextView android:id="#+id/footer"
android:layout_width="fill_parent" android:layout_height="60dp"
android:background="#drawable/box"
android:text="Lazy loading list in steps" android:textStyle="bold"
android:gravity="center_vertical|center_horizontal"
android:layout_alignParentBottom="true" />
<ListView android:id="#+id/list"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:layout_alignParentTop="true" android:layout_above="#id/footer" />
</RelativeLayout>
For the Load more data button to always appear after the last item of the initial list (even if need to scroll to it), I put it into the list's item renderer layout. This way the list will have two item renderers.
The common renderer res/layout/row.xml:
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/textView" android:layout_alignParentRight="true"
android:layout_width="fill_parent" android:layout_height="60dp"
android:gravity="center_vertical|right" android:paddingRight="10dp"
android:textSize="35dp"
android:textColor="#2B78E4" />
is a simple TextView, and the renderer for the last item (of the initial list)
res/layout/row_with_button.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:orientation="vertical">
<TextView android:id="#+id/textView"
android:layout_alignParentRight="true"
android:layout_width="fill_parent" android:layout_height="60dp"
android:gravity="center_vertical|right" android:paddingRight="10dp"
android:layout_weight="1" android:textColor="#2B78E4"
android:textSize="35dp" />
<Button android:id="#+id/loadbtn"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:layout_weight="1" android:text="Load more data"
android:onClick="loadMoreData" />
</LinearLayout>
Finally the Activity class that connects these layouts:
SteppingListActivity.java:
public class SteppingListActivity extends Activity
{
private MyAdapter adapter;
private ArrayList<Integer> values;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.stepping_list);
//initialize the list of data which will populate the list
//TODO: You need to retrieve this data from the server, but I use
// here simple int values.
values = new ArrayList<Integer>();
for (int i = 0; i < 5; i++)
{
values.add((i % 2 == 0) ? i * 3 : i + 3);
}
//initialize the adapter, and attach it to the ListView:
adapter = new MyAdapter();
final ListView listView = (ListView) findViewById(R.id.list);
listView.setAdapter(adapter);
}
/**
* The onClick function of the last itemrenderer's button
* #param button the button clicked.
*/
public void loadMoreData(View button)
{
//Just put some more data into the values ArrayList:
//TODO: You need to retrieve these data from the server, as well!
for (int i = 5; i < 30; i++)
{
values.add((i % 2 == 0) ? i * 3 : i + 3);
}
//notify the ListAdapter about the changes:
adapter.notifyDataSetChanged();
}
/**
* The custom ListAdapter class used to populate the ListView
*/
private class MyAdapter extends BaseAdapter
{
private LayoutInflater inflater;
public MyAdapter()
{
inflater = LayoutInflater.from(SteppingListActivity.this);
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
//check if the current item to show is the last item of the
// initial list, and if so, inflate the proper renderer for it:
if ((position == 4) && (values.size() == 5))
convertView = inflater.inflate(
R.layout.row_with_button, parent, false);
else if ((convertView == null) ||
(convertView.findViewById(R.id.loadbtn) != null))
convertView = inflater.inflate(R.layout.row, parent, false);
//set the value of the TextView
((TextView) convertView.findViewById(
R.id.textView)).setText(values.get(position)+ ".50 €");
return convertView;
}
#Override
public int getCount()
{
return values.size();
}
#Override
public Object getItem(int position)
{
return values.get(position);
}
#Override
public long getItemId(int position)
{
return position;
}
}
}
I hope you got the idea :)
I have an Activity that retrieves data from a web service. This data is presented in a ListView via an ArrayAdapter which inflates a RelativeLayout with three TextViews inside, nothing fancy and it work fine.
Now I want to implement a Details Activity that should be called when a user clicks an item in the ListView, sounds easy but I can't for the life of me get the onItemClickListener to work on my ArrayAdapter.
This is my main Activity:
public class Schema extends Activity {
private ArrayList<Lesson> lessons = new ArrayList<Lesson>();
private static final String TAG = "Schema";
ListView lstLessons;
Integer lessonId;
// called when the activity is first created.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// can we use the custom titlebar?
requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
// set the view
setContentView(R.layout.main);
// set the title
getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.titlebar);
// listview called lstLessons
lstLessons = (ListView)findViewById(R.id.lstLessons);
// load the schema
new loadSchema().execute();
// set the click listeners
lstLessons.setOnItemClickListener(selectLesson);
}// onCreate
// declare an OnItemClickListener for the AdapterArray (this doesn't work)
private OnItemClickListener selectLesson = new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View v, int i, long l) {
Log.v(TAG, "onItemClick fired!");
}
};
private class loadSchema extends AsyncTask<Void, Void, Void> {
private ProgressDialog progressDialog;
// ui calling possible
protected void onPreExecute() {
progressDialog = ProgressDialog.show(Schema.this,"", "Please wait...", true);
}
// no ui from this one
#Override
protected Void doInBackground(Void... arg0) {
// get some JSON, this works fine
}
#Override
protected void onPostExecute(Void result) {
progressDialog.dismiss();
// apply to list adapter
lstLessons.setAdapter(new LessonListAdapter(Schema.this, R.layout.list_item, lessons));
}
My ArrayAdapter code:
// custom ArrayAdapter for Lessons
private class LessonListAdapter extends ArrayAdapter<Lesson> {
private ArrayList<Lesson> lessons;
public LessonListAdapter(Context context, int textViewResourceId, ArrayList<Lesson> items) {
super(context, textViewResourceId, items);
this.lessons = items;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.list_item, null);
}
Lesson o = lessons.get(position);
TextView tt = (TextView) v.findViewById(R.id.titletext);
TextView bt = (TextView) v.findViewById(R.id.timestarttext);
TextView rt = (TextView) v.findViewById(R.id.roomtext);
v.setClickable(true);
v.setFocusable(true);
tt.setText(o.title);
bt.setText(o.fmt_time_start);
rt.setText(o.room);
return v;
}
}// LessonListAdapter
The main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout android:id="#+id/main"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent" android:layout_width="fill_parent"
android:screenOrientation="portrait"
>
<!-- student name -->
<TextView
android:id="#+id/schema_view_student"
android:text="Name" android:padding="4dip"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:gravity="center_vertical|center_horizontal"
style="#style/schema_view_student"
/>
<!-- date for schema -->
<TextView
android:id="#+id/schema_view_title"
android:layout_height="wrap_content"
android:layout_margin="0dip"
style="#style/schema_view_day"
android:gravity="center_vertical|center_horizontal"
android:layout_below="#+id/schema_view_student"
android:text="Date" android:padding="6dip"
android:layout_width="fill_parent"
/>
<!-- horizontal line -->
<View
android:layout_width="fill_parent"
android:layout_height="1dip"
android:background="#55000000"
android:layout_below="#+id/schema_view_title"
/>
<!-- list of lessons -->
<ListView
android:id="#+id/lstLessons"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_below="#+id/schema_view_title"
/>
</RelativeLayout>
The list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="60px"
android:padding="12dip">
<TextView
android:id="#+id/timestarttext"
android:text="09:45"
style="#style/LessonTimeStartText"
android:layout_width="60dip"
android:layout_alignParentTop="true"
android:layout_alignParentBottom="true"
android:layout_height="fill_parent" android:gravity="center_vertical|right" android:paddingRight="6dip"/>
<TextView
android:id="#+id/titletext"
android:text="Test"
style="#style/LessonTitleText"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_toRightOf="#+id/timestarttext"
android:layout_alignParentTop="true"
android:layout_alignParentBottom="true" android:gravity="center_vertical|center_horizontal"/>
<TextView
android:id="#+id/roomtext"
android:text="123"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
style="#style/LessonRoomText"
android:layout_alignParentTop="true"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:gravity="center_vertical" />
</RelativeLayout>
Been messing with this for the last couple of hours and I can't seem to get my head around what the problem is. My problem looks very similar to this question, but I'm not extending ListActivity, so I still don't know where my onListClickItem() should go.
UPDATE: Now I've puzzled with this for several days and still can't find the issue.
Should I rewrite the activity, this time extending ListActivity instead of Activity? Because it provides the onItemClick method itself and is probably easier to overwrite.
Or, should I bind a listener directly in each getView() in my ArrayAdapter? I believe I have read this is bad practice (I should do as I tried and failed in my post).
Found the bug - it seems to be this issue. Adding android:focusable="false" to each of the list_item.xml elements solved the issue, and the onclick is now triggered with the original code.
I've encountered the same issue and tried your fix but couldn't get it to work. What worked for me was adding android:descendantFocusability="blocksDescendants" to the <RelativeLayout> from the item layout xml, list_item.xml in your case. This allows onItemClick() to be called.
What worked for me :
1) Adding android:descendantFocusability="blocksDescendants" to Relative Layout tag.
The result is shown below :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:descendantFocusability="blocksDescendants" >
2) Adding android:focusable="false" to every element in in list_item.xml
example :
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:focusable="false" />
Once I had a similar problem. Every list item had a text view and a checkbox, and just because the checkbox, the whole listitem wasn't 'enabled' to fire the event. I solved it by making a little trick inside the adapter when I was getting the view.
Just before returning the view I put:
v.setOnClickListener(listener);
(The object listener is an onItemClickListener I gave to the Adapter's constructor).
But I have to tell you, the problem is because the platform, it is a bug.
I had the same problem and I tried to solve it by adding
android:focusableInTouchMode="false"
android:clickable="false"
android:focusable="false"
to my item.xml but it still doesn't work !!! Infact I found the issue in the relative layout witch contains
android:focusableInTouchMode="true" android:focusable="true"
And when I removed it All things is ok
protected void onPostExecute(Void result) {
progressDialog.dismiss(); stLessons.setAdapter(new LessonListAdapter(Schema.this, R.layout.list_item, lessons));
//add this
ListView lv = getListView(); lv.setOnItemClickListener(new ListView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> a, View v, int i, long l) {
//do stuff
}
});
}