I should want a non scrollable ListView, and show the entire ListView. It's because my entire screen is a ScrollView, and I dispatch widgets with a RelativeLayout, so I don't need the ListView scroll.
I set my ui with code, not with xml.
I've used listView.setScrollContainer(false), but it's not work, I don't understand why.
Thanks.
I found a very simple solution for this. Just get the adapter of the listview and calculate its size when all items are shown.
The advantage is that this solution also works inside a ScrollView.
Example:
public void justifyListViewHeightBasedOnChildren (ListView listView) {
ListAdapter adapter = listView.getAdapter();
if (adapter == null) {
return;
}
ViewGroup vg = listView;
int totalHeight = 0;
for (int i = 0; i < adapter.getCount(); i++) {
View listItem = adapter.getView(i, null, vg);
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams par = listView.getLayoutParams();
par.height = totalHeight + (listView.getDividerHeight() * (adapter.getCount() - 1));
listView.setLayoutParams(par);
listView.requestLayout();
}
Call this function passing over your ListView object:
justifyListViewHeightBasedOnChildren(myListview);
The function shown above is a modification of a post in:
Disable scrolling in listview
Please note to call this function after you have set the adapter to the listview. If the size of entries in the adapter has changed, you need to call this function as well.
The correct answer is here.
Just assign this listener to your ListView:
listView.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_MOVE) {
return true; // Indicates that this has been handled by you and will not be forwarded further.
}
return false;
}
});
Don't put a listview in a scrollview, it doesn't work. If you want a list of items that doesn't scroll, it's called a linearlayout.
Depending on what exactly you are trying to do, you may be able to solve your problem by ditching the ScrollView and instead using ListView's addHeaderView(View) and addFooterView(View).
I came up with BaseAdapterUnscrollable. Basically it just adds views to ViewGroup container. Implementation is a bit like BaseAdapter. It’s pretty convenient if you use a few non-scrollable lists like that in you project.
In onCreate:
PeopleAdapter peopleAdapter = new PeopleAdapter(this, personList, containerPeopleLinearLayout);
peopleAdapter.setOnItemClickListener(this);
peopleAdapter.drawItems();
Your specific adapter:
public class PeopleAdapter extends BaseAdapterNonScrollable<Person> {
public PeopleAdapter(Context context, List<Person> items, LinearLayout container) {
super(context, items, container);
}
#Override
public View getView(View container, Person person) {
TextView textView = (TextView) LayoutInflater.from(context).inflate(android.R.layout.simple_list_item_1, null);
textView.setText(person.getName());
return textView;
}
}
BaseAdapterNonScrollable (just copy):
public abstract class BaseAdapterNonScrollable<T> implements NonScrollable, OnItemClick {
public Context context;
private ViewGroup containerViewGroup;
private List<T> itemObjectList;
private OnItemClick itemClickListener;
public BaseAdapterNonScrollable(Context context, List<T> items, ViewGroup containerViewGroup) {
this.context = context;
this.itemObjectList = items;
this.containerViewGroup = containerViewGroup;
}
#Override
public void drawItems() {
if (containerViewGroup == null || itemObjectList.size() == 0) {
return;
}
if (containerViewGroup.getChildCount() > 0) {
containerViewGroup.removeAllViews();
}
//draw all items
for (int i = 0; i < itemObjectList.size(); i++) {
final int position = i;
final View itemView = getView(containerViewGroup, itemObjectList.get(i));
if (itemView != null) {
containerViewGroup.addView(itemView);
//handle item click event
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (itemClickListener != null) {
itemClickListener.onItemClick(itemObjectList, position);
}
}
});
}
}
}
public void setOnItemClickListener(OnItemClick onItemClick) {
this.itemClickListener = onItemClick;
}
public abstract View getView(View container, T itemObject);
#Override
public void onItemClick(List<?> itemList, int position) {
}
}
Interfaces
public interface NonScrollable {
void drawItems();
}
public interface OnItemClick {
void onItemClick(List<?> itemList, int position);
}
to disable scrolling you can use listview.setEnabled(false)
This also disables row selections.
I have achieve this by passing in physics property into the ListView:
ListView.builder(
---> physics: ScrollPhysics(), <-----
shrinkWrap: true,
itemCount: items.length,
itemBuilder: (context, index) {
return //ListTile or whatever
Note: This ListView is inside of a column with other widgets, and the column is wrapped in SingleChildScrollView
Related
I am having an issue updating the ListView in my Android application. I have searched for the solution and read multiple answers but none solved my issue:
android-listview-repeating-old-data-after-refresh
android-requestlayout-improperly-called
android-listview-not-refreshing-after-notifydatasetchanged
android-listview-getview-being-called-multiple-times-on-unobservable-views
Issue
I have a listview with 2 items displayed like this:
Item 1 (position 0)
Item 2 (position 1)
After reloading the data from the source I get the same 2 items, but in the listview it is displayed like this:
Item 2 (position 0)
Item 2 (position 1)
However, when I click on the position 0 in new list it shows correct data of Item 1 (click on position 1 it also shows correct data of Item 2).
The problem is that it displays Item 2 on position 0 and on position 1 (twice).
Here is the code where list is updated and adapter is setup:
public class FishTankFragment extends DeviceFragment {
...
private final List<FishTankStatus.Schedule> schedulesList = new ArrayList<>();
private ScheduleAdapter scheduleAdapter;
...
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
...
scheduleAdapter = new ScheduleAdapter(view.getContext(), schedulesList);
screenBinding.lvSchedules.setAdapter(scheduleAdapter);
screenBinding.lvSchedules.setOnItemClickListener((parent, view1, position, id) -> {
new ScheduleItemClickListener(this.getContext(), schedulesList.get(position), position);
});
...
}
#Override
public <T> void onResponse(T responseObject) {
...
schedulesList.clear();
schedulesList.addAll(data.getSchedules());
scheduleAdapter.notifyDataSetChanged();
...
}
Here is Adapter code:
public class ScheduleAdapter extends BaseAdapter {
private ScheduleItemBinding itemBinding;
private final List<FishTankStatus.Schedule> schedules;
private final Context context;
public ScheduleAdapter(#NonNull Context context, #NonNull List<FishTankStatus.Schedule> objects) {
this.context = context;
schedules = objects;
}
#Override
public int getCount() {
return schedules.size();
}
#Override
public FishTankStatus.Schedule getItem(int position) {
return schedules.get(position);
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(int position, View view, ViewGroup parent) {
if (view == null) {
itemBinding = ScheduleItemBinding.inflate(LayoutInflater.from(context));
view = itemBinding.getRoot();
}
if (!schedules.isEmpty()) {
String start = StringUtils.printTime(schedules.get(position).getStart());
String end = StringUtils.printTime(schedules.get(position).getEnd());
itemBinding.tvScheduleStart.setText(start);
itemBinding.tvScheduleEnd.setText(end);
FishTankStatus.Schedule schedule = schedules.get(position);
for (String device : schedule.getDevices()) {
switch (device) {
case "something":
itemBinding.ivYellowlightIcon.setVisibility(View.VISIBLE);
break;
case "something 1":
itemBinding.ivBluelightIcon.setVisibility(View.VISIBLE);
break;
case "something 2":
itemBinding.ivAirIcon.setVisibility(View.VISIBLE);
}
}
if (schedules.get(position).getActive()) {
ColorStateList white = ColorStateList.valueOf(
view.getResources().getColor(R.color.white, view.getContext().getTheme()));
itemBinding.lySchedule.setBackground(ResourcesCompat.getDrawable(view.getResources(),
R.drawable.rectangle_p_light_8,
view.getContext().getTheme()));
...
}
}
return view;
}
}
ListView has width and height set to match_parent in parent ConstraintLayout where width=0dp (has parent) and height=match_parent
See the video:
screen recording
Thank you for all the help.
I debugged the app. After clearing schedulesList.clear() it contained 0 items in Fragment and also in BaseAdapter. After addAll items from the source it contained correct items in schedulesList both in Fragment and BaseAdapter.
I tried to fill the data in Adapter as separate List object using clear and addAll.
I will answer my own question for the future visitors...
Just use RecyclerView
It solved all my issues. But I still do not know why the above problem happened.
I have problems with RecyclerView when I try to loop adding more child views to the parent view. When I scroll, it appears blank for a second. Is from Data binding or the view rendering?
Here is my code:
public class TournamentFixtureAdapter extends LoadMoreRecyclerViewAdapter<FixtureGroup> {
private OnFixtureClickListener onFixtureClickListener = null;
public TournamentFixtureAdapter(List<FixtureGroup> data) {
super(data);
}
#Override
protected RecyclerView.ViewHolder onCreateContentItemViewHolder(ViewGroup parent, int contentViewType) {
return new TournamentFixtureHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_tournament_fixture, parent, false));
}
#Override
protected void onBindContentItemViewHolder(RecyclerView.ViewHolder holder, int position) {
super.onBindContentItemViewHolder(holder, position);
FixtureGroup fixtureGroup = data.get(position);
((TournamentFixtureHolder) holder).onFixtureClickListener = onFixtureClickListener;
((TournamentFixtureHolder) holder).parentPos = position;
((TournamentFixtureHolder) holder).binding.setFixtureGroup(fixtureGroup);
((TournamentFixtureHolder) holder).addFixtures(fixtureGroup.getFixtures());
}
public void setOnFixtureClickListener(OnFixtureClickListener onFixtureClickListener) {
this.onFixtureClickListener = onFixtureClickListener;
}
static class TournamentFixtureHolder extends FixtureHolder {
ListItemTournamentFixtureBinding binding = null;
public TournamentFixtureHolder(View itemView) {
super(itemView);
binding = DataBindingUtil.bind(itemView);
}
}
}
public class FixtureHolder extends BaseAdapter.BaseHolder {
LinearLayout layoutMain = null;
OnFixtureClickListener onFixtureClickListener = null;
int parentPos;
public FixtureHolder(View itemView) {
super(itemView);
layoutMain = (LinearLayout) itemView.findViewById(R.id.layout_main);
setIsRecyclable(layoutMain.getChildCount() > 0);
}
public void addFixtures(final ArrayList<Fixture> fixtures) {
for (final Fixture fixture : fixtures) {
LinearLayout parent = (LinearLayout) LayoutInflater.from(itemView.getContext()).inflate(R.layout.view_fixture, null);
Utils.getDefaultClubLogo((NetworkImageViewPlus) parent.findViewById(R.id.netview_home_img)).setImageUrl(fixture.getHome().getImg(), AppController.getInstance().getImageLoader());
Utils.getDefaultClubLogo((NetworkImageViewPlus) parent.findViewById(R.id.netview_away_img)).setImageUrl(fixture.getAway().getImg(), AppController.getInstance().getImageLoader());
ViewFixtureBinding binding = DataBindingUtil.bind(parent);
layoutMain.addView(parent);
binding.setFixture(fixture);
parent.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onFixtureClickListener.onFixtureClick(parentPos, findFixturePosById(fixtures, fixture.getId()));
}
});
}
}
private int findFixturePosById(ArrayList<Fixture> fixtures, int id) {
for (int i = 0; i < fixtures.size(); i++) {
if (fixtures.get(i).getId() == id) {
return i;
}
}
return 0;
}
}
If the problem was more on the data side (adapter), then it would probably be showing up on the normal layout, not just during scrolling. For instance, if you were loading images from a slow server, the initial display would be slow. Since it's only happening when you scroll, that points more to a problem with the layout manager.
For every new view, you have to get it from the adapter, and add it to the layout. If you allow maximum dx in horizontal/vertical scrolling, and have recycled views outside of the screen display cached, it's likely that things will appear blank prior the layout manager getting the new views from the adapter and laying them out.
So there are two factors - horizontal and/or vertical dx is too large, too soon, and the number of recycled (or scrapped) views is too small. So the solution is to either slow down scrolling, or to increase the number of views you are adding off-screen.
I have implemented a custom adapter and listItemView. The adapter sets an onlclick listener to a button that is on the listItemView. The onclick listener simply calls a private method I have in the adapter and passes it the position of the item to be removed. I know the position is correct because the database removes the proper item. I have found similar questions but have not been able to adapt the answers to work for me. Ideas and thoughts are greatly appreciated. Thanks.
Here is the full adapter class
public class FoodListAdapter extends ArrayAdapter<FoodListItem> {
//private
private int type;
public FoodListAdapter(Context context, ArrayList<FoodListItem> _objects) {
super(context, 0, _objects);
type = 0;
}
public FoodListAdapter(Context context, ArrayList<FoodListItem> _objects, int _type) {
super(context, 0, _objects);
type = _type;
}
#Override
public View getView(int position, View reusableView, ViewGroup parent)
{
//Cast the reusable view to a listAdpaterItemView
FoodListItemView listItemView = (FoodListItemView) reusableView;
//Check if the listAdapterItem is null
if(listItemView == null)
{
//If it is null, then create a view.
listItemView = FoodListItemView.inflate(parent, this, type);
}
if (type == 2)
{
Button deleteButton = (Button) listItemView.findViewById(R.id.listItemViewDeleteBTN);
deleteButton.setTag(new Integer(position));
}
//Now we need to set the view to display the data.
listItemView.setData(getItem(position));
return listItemView;
}
}
Here is a portion of my code used in fragment. Note that I have a private variable decalred in the class for listAdapter, though I don't think I need that.
private void displayListForDate(Calendar _date)
{
//get the list view
ListView listView = (ListView) getView().findViewById(1);
//Clear the listview by removing the listadapter and setting it to null.
//listView.setAdapter(null);
//First we must get the items.
Global global = (Global) getActivity().getApplicationContext();
DietSQLiteHelper database = global.getDatabase();
//Create a list to hold the items we ate. This list will then be added to the listView.
final ArrayList<FoodListItem> consumedList;
//Add the items to the array.
consumedList = database.getConsumed(_date.getTimeInMillis());
//Create an adapter to be used by the listView
listAdapter = new FoodListAdapter(getActivity().getBaseContext(), consumedList, 2);
//Add the adapter to the listView.
listView.setAdapter(listAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
consumedList.remove(position);
listAdapter.notifyDataSetChanged();
}
});
}
If you didn't implement "equals" method of FoodListItem, try to implements it.
I would suggest,
that you just update the underlying data, in your case its ArrayList<FoodItems>.
In your Adapter make this simple method and change :
private List<FoodListItem> myList = new ArrayList<FoodListItem>();
public FoodListAdapter(Context context, List<FoodListItem> myList) {
super(context, 0, myList);
type = 0;
this.myList = myList;
}
public FoodListAdapter(Context context, List<FoodListItem> myList, int _type) {
super(context, 0, myList);
type = _type;
this.myList = myList;
}
// Also update your getView() method to use myList!
#Override
public View getView(int position, View reusableView, ViewGroup parent)
{
...
listItemView.setData(myList.get(position));
public void removeItem(int positio){
if(myList != null){
myList.remove(position);
}
}
And then in class, you are creating the adapter (Activity/Fragment), just call the method.
// Update the underlying ArrayAdapter
adapter.removeItem(position);
// Notify the adapter, the data has changed
adapter.notifyDataSetChanged();
Also, you shouldnt open connection to your SQLiteDatabase on UI thread, because you are blocking it. You never know, how fast is the reading from disk going to be. If it takes too long, user can think, that your application froze and therefore, he leaves, which you dont want. I would suggest to use AsyncTask, you will find a lot of examples.
I went through and cleaned up my code and it now works, here is the working code. I really don't know exactly the difference other than I updated the IDs that I was using to assign and get views. If anyone can explain the cause for the issue I was having I would appreciate it.
Here is the snippet from my fragment where I create the list view and assign an adapter.
private void displayListForDate(Calendar _date)
{
//get the list view
ListView listView = (ListView) getView().findViewById(R.id.listView);
//Clear the listview by removing the listadapter and setting it to null.
//listView.setAdapter(null);
//First we must get the items.
Global global = (Global) getActivity().getApplicationContext();
DietSQLiteHelper database = global.getDatabase();
//Create a list to hold the items we ate. This list will then be added to the listView.
ArrayList<FoodListItem> consumedList;
//Add the items to the array.
consumedList = database.getConsumed(_date.getTimeInMillis());
//Create an adapter to be used by the listView
listAdapter = new FoodListAdapter(getActivity().getBaseContext(), consumedList, 2);
//Add the adapter to the listView.
listView.setAdapter(listAdapter);
}
and here is my adapter class.
public class FoodListAdapter extends ArrayAdapter<FoodListItem>
{
//private
private int type;
public FoodListAdapter(Context context, ArrayList<FoodListItem> _objects) {
super(context, 0, _objects);
type = 0;
}
public FoodListAdapter(Context context, ArrayList<FoodListItem> _objects, int _type) {
super(context, 0, _objects);
type = _type;
}
#Override
public View getView(int position, View reusableView, ViewGroup parent)
{
//Cast the reusable view to a listAdpaterItemView
FoodListItemView listItemView = (FoodListItemView) reusableView;
//Check if the listAdapterItem is null
if(listItemView == null)
{
//If it is null, then create a view.
listItemView = FoodListItemView.inflate(parent, type);
}
if (type == 2)
{
Button deleteButton = (Button) listItemView.findViewById(R.id.listItemViewDeleteBTN);
deleteButton.setTag(new Integer(position));
deleteButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Integer tag = (Integer) view.getTag();
deleteItem(tag.intValue());
}
});
}
//Now we need to set the view to display the data.
listItemView.setData(getItem(position));
return listItemView;
}
private void deleteItem(int position)
{
FoodListItem item = getItem(position);
Global global = (Global) getContext().getApplicationContext();
DietSQLiteHelper database = global.getDatabase();
database.removeConsumed(item.getID());
remove(getItem(position));
}
}
I have an Activity that hosts multiple fragments using the actionbar's tab functionality. One of those fragments contains a ListView. Upon this tab being selected, I'd like to select a certain item.
To do this programmatically, I use the following code (where calls is the ListView)
private void selectItem(int position)
{
long itemId = calls.GetItemIdAtPosition(position);
calls.PerformItemClick(calls, position, itemId);
}
If this ListView has been rendered, and I'm calling this, no problem. However, if I call it from onResume, then the code executes but nothing is selected in the end. I figure this is because at the point where I'm calling selectItem, not all items of the ListView have been rendered yet. If however I start off a background thread, sleep for a couple hundred milliseconds, then run the same code (in the ui thread of course), everything is fine, but this is an ugly hack.
Now you might be wondering, "why isn't he using calls.setSelection"? The thing is, I'm using a custom layout that performs expansion - so I need to actually click on the item I want selected (which in turn triggers the layout expansion for the item selected). However, I can call the code that is performed on PerformItemClick directly, the results will be the same (the layout expansion isn't performed).
Isn't there any way for me to catch the "Listview has finished rendering all viewable items" point in time, and then execute my selectItem call at that point? In ASP.NET, I have an event on every UI item telling me when it is done rendering, so I do item selection at that point but I haven't found anything.
Regards
Stephan
Here's the Adapter I'm using
public class ActiveCallsAdapter: ObservableAdapter<Call>
{
public ActiveCallsAdapter(Activity activity, ObservableCollection<Call> calls)
: base(activity, calls)
{
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var item = items[position];
var view = (convertView ?? context.LayoutInflater.Inflate(Resource.Layout.Call, parent, false)) as LinearLayout;
//View view = convertView;
//if (view == null) // no view to re-use, create new
// view = context.LayoutInflater.Inflate(Resource.Layout.Call, null);
SetTextView(view, Resource.Id.CallerName, item.CallerName);
SetTextView(view, Resource.Id.CallerNumber, item.CallerNumber);
SetTextView(view, Resource.Id.CallStatus, item.State.ToString());
SetTextView(view, Resource.Id.CallDuration, item.Duration);
return view;
}
public void Update(LinearLayout view, Call item)
{
SetTextView(view, Resource.Id.CallerName, item.CallerName);
SetTextView(view, Resource.Id.CallerNumber, item.CallerNumber);
string identifier = "callState_" + item.State.ToString();
int resourceId = Application.Context.Resources.GetIdentifier(identifier, "string", Application.Context.PackageName);
string callStateString = item.State.ToString();
if (resourceId != 0)
{
try
{
callStateString = Application.Context.Resources.GetString(resourceId);
}
catch (Exception e)
{
AndroidLogModel.Model.AddLogMessage("ActiveCallsAdapter", "Unable to find call state string with resource id " + resourceId + " state string: " + identifier, 3);
}
}
SetTextView(view, Resource.Id.CallStatus, callStateString);
//SetTextView(view, Resource.Id.CallDuration, item.Duration);
}
public void UpdateDuration(LinearLayout view, Call item)
{
SetTextView(view, Resource.Id.CallDuration, item.Duration);
}
}
And the base class of that adapter
public class ObservableAdapter<T>: BaseAdapter<T>
{
protected readonly Activity context;
protected readonly ObservableCollection<T> items;
public ObservableAdapter(Activity context, ObservableCollection<T> collection)
{
this.context = context;
this.items = collection;
//this.collection.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(collection_CollectionChanged);
this.items.CollectionChanged += (sender, e) => NotifyDataSetChanged();
}
void collection_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
NotifyDataSetChanged();
}
public override T this[int position]
{
get { return items[position]; }
}
public override int Count
{
get { return items.Count; }
}
public override long GetItemId(int position)
{
return position;
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var item = items[position];
var view = (convertView ?? context.LayoutInflater.Inflate(Resource.Layout.Call, parent, false)) as LinearLayout;
// configure view here
return view;
}
protected void SetTextView(LinearLayout view, int id, string text)
{
var textView = view.FindViewById<TextView>(id);
if (textView != null)
textView.SetText(text, TextView.BufferType.Normal);
}
}
My Mono skills are limited so I don't know if I fully understood your adapter, anyway I've adapted some old code and made an adapter that expands a single item when click, also it will move the ListView in onResume to a desired position:
private static class CustomAdapter extends BaseAdapter {
// the data
private ArrayList<String> mData;
// an int pointing to a position that has an expanded layout,
// for simplicity I assume that you expand only one item(otherwise use
// an array or list)
private int mExpandedPosition = -1; // -1 meaning no expanded item
private LayoutInflater mInflater;
public CustomAdapter(Context context, ArrayList<String> items) {
mInflater = LayoutInflater.from(context);
mData = items;
}
public void setExpandedPosition(int position) {
// if the position equals mExpandedPosition then we have a click on
// the same row so simply toggle the row to be gone again
if (position == mExpandedPosition) {
mExpandedPosition = -1;
} else {
// else change position of the row that was expanded
mExpandedPosition = position;
}
// notify the adapter
notifyDataSetChanged();
}
#Override
public int getCount() {
return mData.size();
}
#Override
public String getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = mInflater.inflate(R.layout.ad_expandedelement,
parent, false);
}
((TextView) convertView.findViewById(R.id.textView1))
.setText(getItem(position));
// see if there is an expanded position and if we are at that
// position
if (mExpandedPosition != -1 && mExpandedPosition == position) {
// if yes simply expand the layout
convertView.findViewById(R.id.button1).setVisibility(
View.VISIBLE);
} else {
// this is required, we must revert any possible changes
// otherwise the recycling mechanism will hurt us
convertView.findViewById(R.id.button1).setVisibility(View.GONE);
}
return convertView;
}
}
The onListItemClick will simply be:
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
// set the expanded(or collapsed if it's a click on the same row that
// was previously expanded) row in the adapter
((CustomAdapter) getListView().getAdapter())
.setExpandedPosition(position);
}
and in onResume will have:
#Override
protected void onResume() {
super.onResume();
// set the position to the desired element
((CustomAdapter) getListView().getAdapter()).setExpandedPosition(15);
// set the selection to that element so we can actually see it
// this isn't required but has the advantage that it will move the
// ListView to the desired
// position if not visible
getListView().setSelection(15);
}
The R.layout.ad_expandedelement is a simple vertical LinearLayout with a TextView and an initially hidden(visibility set to gone) Button. For this Button I change the visibility to simulate expanding/collapsing a row in the ListView. You should be able to understand my code, if you want I can post on github the full sample.
While I'm not sure of the exact equivalent in C#/Mono, the Android framework provides a callback on Activity called onWindowFocusChanged() that indicates the period when the Window associated with a given Activity is visible to the user. You may have better luck waiting to call your selection method until that time, as the ListView should be measured and laid out by that point. In Java, it would be something like this:
#Override
public void onWindowFocusChanged (boolean hasFocus) {
if (hasFocus) {
selectItem(position);
}
}
You may need to have a bit more logic in there, this callback is directly associated with window focus and isn't a true lifecycle method. I can get called multiple times if you are displaying Dialogs or doing other similar operations.
I have a custom configuration page in my app which just so happens to contain a ListView which you can select/deselect, edit, add to and remove items from. Since the amount of configuration is so large I've had to put it all in a ScrollView
My problem is of course that you cannot have scroll functionality within a view which already has it's own scroll functionality. This means I can't have a scrolling ListView inside a ScrollView.
What I've been trying to do is find the best way of limiting the damage this does. I've seen suggestions that say "You could just create a LinearLayout which grows as you add more children". That would work find by the added effort required to plug in the selectable nature, the reordering & sorting of the list as well as the editing would be a maintanance nightmare.
I've spent the day trying to find a way of measuring the height of each ListView item. Once I can find the size of each item (not just the content but any padding and space between items) on each device I know I can simply change the height of the ListView per item added.
Unfortunately I can't seem to find a way to reliably pull back the height of a listviews child.
(The old chestnut of using a GlobalLayoutListener doesn't help me pull back the padding between items)
final TextView listLabel = (TextView) toReturn.findViewById(R.id.listLabel);
final ViewTreeObserver vto = listLabel.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
listLabel.getViewTreeObserver().removeGlobalOnLayoutListener(this);
mListItemHeight = listLabel.getHeight();
}
});
Maybe you're trying to display too many details on your page? You could split the activity in a summary with buttons that lead to multiple one-screen-long activities.
In my experience, users usually prefer an uncluttered and clear view, even if that means having to click once or twice to get to the part they want.
EDIT
Expanding ListView's are you're friend - This LinearLayout expands based on it's content. It allows Dynamic ListView's inside of ScrollView.
public class LinearListView extends LinearLayout {
private BaseAdapter mAdapter;
private Observer mObserver;
private OnItemClickListener mOnItemClickListener;
private OnItemLongClickListener mOnItemLongClickListener;
public LinearListView(Context context) {
super(context);
init();
}
public LinearListView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public LinearListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
mObserver = new Observer();
}
public void setAdapter(BaseAdapter adapter) {
if (this.mAdapter != null)
this.mAdapter.unregisterDataSetObserver(mObserver);
this.mAdapter = adapter;
adapter.registerDataSetObserver(mObserver);
mObserver.onChanged();
}
public void setOnItemClickListener(OnItemClickListener listener) {
mOnItemClickListener = listener;
}
public void setOnItemLongClickListener(OnItemLongClickListener listener) {
mOnItemLongClickListener = listener;
}
private int mListSelector = R.drawable.selector_list;
public void setListSelector(int resid) {
mListSelector = resid;
}
private class Observer extends DataSetObserver {
public Observer(){}
#Override
public void onChanged() {
List<View> oldViews = new ArrayList<View>(getChildCount());
for (int i = 0; i < getChildCount(); i++)
oldViews.add(getChildAt(i));
Iterator<View> iter = oldViews.iterator();
removeAllViews();
for (int i = 0; i < mAdapter.getCount(); i++) {
final int index = i;
View convertView = iter.hasNext() ? iter.next() : null;
View toAdd = mAdapter.getView(i, convertView, LinearListView.this);
toAdd.setBackgroundResource(mListSelector);
toAdd.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if(mOnItemClickListener != null) {
mOnItemClickListener.onItemClick(null, v, index, index);
}
}
});
toAdd.setOnLongClickListener(new OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
if(mOnItemLongClickListener != null) {
mOnItemLongClickListener.onItemLongClick(null, v, index, index);
}
return true;
}
});
LinearListView.this.addView(toAdd, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
}
super.onChanged();
}
#Override
public void onInvalidated() {
removeAllViews();
super.onInvalidated();
}
}
}