I am developing a Xamarin app for android using Xamarin forms to create my layout. I have come across an issue with my time picker firing on load of my view cell.
What I am doing is creating a list view and then setting the item template to my custom view cell template. In my view cell template I am creating a TimePicker and binding a PropertyChanged event to it. I am also setting the TimePicker.Time property with information retrieved from the database. What seems to happen at this point is that my PropertyChanged event is fired for each item that will be displayed in the list view. This leads to multiple database calls that are not needed.
Is there a way to stop the PropertyChanged event being called until a property has actually been changed?
My code is below.
public class MyCell : ViewCell
{
private readonly TimePicker _myTimePicker;
public MyCell()
{
_myTimePicker = new TimePicker()
{
HorizontalOptions = LayoutOptions.EndAndExpand
};
_myTimePicker.SetBinding(TimePicker.TimeProperty, "StartTime");
_myTimePicker.PropertyChanged += MyTimePicker_PropertyChanged;
var viewLayout = new StackLayout()
{
HorizontalOptions = LayoutOptions.StartAndExpand,
Orientation = StackOrientation.Horizontal,
Padding = new Thickness(20),
Children = { _myTimePicker }
};
View = viewLayout;
}
private void MyTimePicker_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName == TimePicker.TimeProperty.PropertyName && _myTimePicker.Time != TimeSpan.MinValue)
{
var dataAccess = new DataAccessLayer();
dataAccess.Update(myTimePicker.Time);
}
}
}
I'm not sure why the propertychanged event is fired multiple times and how to stop it firing until I actually pick a time. Any help would be appreciated.
Below is my code for the form to display the list view. All my xaml is defined in code. 'MyCell' uses the values returned from '_dataAccess.GetTimes()'.
public class TimeDetails : ContentPage
{
private ListView _listView;
private readonly DataAccessLayer _dataAccess = new DataAccessLayer();
protected override void OnAppearing()
{
_listView = new ListView
{
RowHeight = 80,
SeparatorColor = Color.Blue,
SeparatorVisibility = SeparatorVisibility.Default
};
_listView.ItemsSource = _dataAccess.GetTimes();
_listView.ItemTemplate = new DataTemplate(typeof(MyCell));
_listView.ItemSelected += ListView_ItemSelected;
Content = new StackLayout
{
VerticalOptions = LayoutOptions.FillAndExpand,
Children = { _listView }
};
}
}
The return type of _dataAcess.GetTimes() is List of TaskTime. The TaskTime model is shown below.
public class TaskTime
{
public int Id { get; set; }
public string Task { get; set; }
public TimeSpan StartTime { get; set; }
}
class MyCell : ViewCell
{
private readonly TimePicker _myTimePicker;
public MyCell()
{
_myTimePicker = new TimePicker()
{
HorizontalOptions = LayoutOptions.EndAndExpand
};
_myTimePicker.SetBinding(TimePicker.TimeProperty, "StartTime");
_myTimePicker.PropertyChanged += MyTimePicker_PropertyChanged;
_myTimePicker.Focused += _myTimePicker_Focused;
var viewLayout = new StackLayout()
{
HorizontalOptions = LayoutOptions.StartAndExpand,
Orientation = StackOrientation.Horizontal,
Padding = new Thickness(20),
Children = { _myTimePicker }
};
View = viewLayout;
}
bool myTimePickerSelected;
private void _myTimePicker_Focused(object sender, FocusEventArgs e)
{
myTimePickerSelected = true;
}
private void MyTimePicker_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName == TimePicker.TimeProperty.PropertyName && myTimePickerSelected)
{
//var dataAccess = new DataAccessLayer();
//dataAccess.Update(myTimePicker.Time);
}
}
}
A simpler solution using focused & unfocused event is :
public class CustomTimePicker : TimePicker
{
public event EventHandler TimeChanged;
private TimeSpan StartValue { get; set; }
public CustomTimePicker ()
{
this.Focused += OnFoused;
this.Unfocused += OnUnfocused;
}
private void OnFoused(object sender, FocusEventArgs e)
{
StartValue = this.Time;
}
private void OnUnfocused(object sender, FocusEventArgs e)
{
if (StartValue != this.Time)
{
TimeChanged?.Invoke(this, e);
}
}
}
what i have seen is that OnAppearing() is finished when all initialization is done. Maybe you could introduce a boolean variable that you then use in PropertyChanged() method. It is a trick because you have to do it from ContentPage, and pass a value to your control when initialization is finished.
I just saw, ther is OnAppearing() method in CellView, this way everything stays in your control class.
Related
I have a list of different mines. Each mine has a list of blocks.
I have the mines in a spinner and the blocks in a recyclerview.
I want to display the different lists of blocks whenever the user changes the mine in the mine spinner
I am using Firebase in the backend as my database.
When I change the mine in the spinner, I update the block list by creating a new MutableLiveData which I've extended in a class called FirebaseQueryLiveData
The first time that I initialise the FirebaseQueryLiveData with the quesry containing the mine name, all the events inside it fire. However, after that, I call it and nothing fires. It breaks in the constructor if I have a breakpoint there, but it never reaches the run() method, onActive() method or the onDataChanged in the ValueEventListener.
I have done some research, and I have seen suggestions to replace the LiveData with MutableLiveData. I've done this, and it doesn't seem to make a difference.
Can anyone see anything in the code which I might be missing? I'm not very familiar with the android architecture components and I got the FirebaseQueryLiveData class from another helpful website with a tutorial, so I'm battling to understand where I have gone wrong.
I have done some research, and I have seen suggestions to replace the LiveData with MutableLiveData. I've done this, and it doesn't seem to make a difference.
public class BlockListActivityViewModel extends ViewModel {
private static DatabaseReference blockOutlineRef; // = FirebaseDatabase.getInstance().getReference(FireBasePaths.BLOCKOUTLINE.getPath("Therisa"));
private static DatabaseReference mineListRef;
private FirebaseQueryLiveData blockOutlineLiveDataQuery = null;
private LiveData<BlockOutlineList> blockOutlineLiveData = null;
private MediatorLiveData<String> selectedBlockNameMutableLiveData;
private MediatorLiveData<ArrayList<String>> mineListMutableLiveData;
public BlockListActivityViewModel() {
User loggedInUser = UserSingleton.getInstance();
setUpFirebasePersistance();
setupMineLiveData(loggedInUser);
// setupBlockOutlineListLiveData();
}
private void setupBlockOutlineListLiveData(String mineName) {
if (mineName != "") {
blockOutlineRef = FirebaseDatabase.getInstance().getReference(FireBasePaths.BLOCKOUTLINE.getPath(mineName));
blockOutlineLiveDataQuery = new FirebaseQueryLiveData(blockOutlineRef);
blockOutlineLiveData = Transformations.map(blockOutlineLiveDataQuery, new BlockOutlineHashMapDeserialiser());
}
}
private void setupMineLiveData(User user) {
ArrayList<String> mineNames = new ArrayList<>();
if (user != null) {
if (user.getWriteMines() != null) {
for (String mineName : user.getWriteMines().values()) {
mineNames.add(mineName);
}
}
}
setMineListMutableLiveData(mineNames);
if (mineNames.size() > 0) {
updateMineLiveData(mineNames.get(0));
}
}
public void updateMineLiveData(String mineName) {
SelectedMineSingleton.setMineName(mineName);
setupBlockOutlineListLiveData(SelectedMineSingleton.getInstance());
}
public void setUpFirebasePersistance() {
int i = 0;
// FirebaseDatabase.getInstance().setPersistenceEnabled(true);
}
private MutableLiveData<NamedBlockOutline> selectedBlockOutlineMutableLiveData;
public MutableLiveData<NamedBlockOutline> getSelectedBlockOutlineMutableLiveData() {
if (selectedBlockOutlineMutableLiveData == null) {
selectedBlockOutlineMutableLiveData = new MutableLiveData<>();
}
return selectedBlockOutlineMutableLiveData;
}
public void setSelectedBlockOutlineMutableLiveData(NamedBlockOutline namedBlockOutline) {
getSelectedBlockOutlineMutableLiveData().postValue(namedBlockOutline);
}
public MediatorLiveData<String> getSelectedBlockNameMutableLiveData() {
if (selectedBlockNameMutableLiveData == null)
selectedBlockNameMutableLiveData = new MediatorLiveData<>();
return selectedBlockNameMutableLiveData;
}
public void setSelectedBlockNameMutableLiveData(String blockName) {
selectedBlockNameMutableLiveData.postValue(blockName);
}
public MediatorLiveData<ArrayList<String>> getMineListMutableLiveData() {
if (mineListMutableLiveData == null)
mineListMutableLiveData = new MediatorLiveData<>();
return mineListMutableLiveData;
}
public void setMineListMutableLiveData(ArrayList<String> mineListString) {
getMineListMutableLiveData().postValue(mineListString);
}
private class BlockOutlineHashMapDeserialiser implements Function<DataSnapshot, BlockOutlineList>, android.arch.core.util.Function<DataSnapshot, BlockOutlineList> {
#Override
public BlockOutlineList apply(DataSnapshot dataSnapshot) {
BlockOutlineList blockOutlineList = new BlockOutlineList();
HashMap<String, NamedBlockOutline> blockOutlineStringHashMap = new HashMap<>();
for (DataSnapshot childData : dataSnapshot.getChildren()) {
NamedBlockOutline thisNamedOutline = new NamedBlockOutline();
HashMap<String, Object> blockOutlinePointHeader = (HashMap<String, Object>) childData.getValue();
HashMap<String, BlockPoint> blockOutlinePoints = (HashMap<String, BlockPoint>) blockOutlinePointHeader.get("blockOutlinePoints");
thisNamedOutline.setBlockName(childData.getKey());
thisNamedOutline.setBlockOutlinePoints(blockOutlinePoints);
blockOutlineStringHashMap.put(childData.getKey(), thisNamedOutline);
}
blockOutlineList.setBlockOutlineHashMap(blockOutlineStringHashMap);
return blockOutlineList;
}
}
#NonNull
public LiveData<BlockOutlineList> getBlockOutlineLiveData() {
return blockOutlineLiveData;
}
}
LiveData
public class FirebaseQueryLiveData extends MutableLiveData<DataSnapshot> {
private static final String LOG_TAG = "FirebaseQueryLiveData";
private final Query query;
private final MyValueEventListener listener = new MyValueEventListener();
private boolean listenerRemovePending = false;
private final Handler handler = new Handler();
public FirebaseQueryLiveData(Query query) {
this.query = query;
}
public FirebaseQueryLiveData(DatabaseReference ref) {
this.query = ref;
}
private final Runnable removeListener = new Runnable() {
#Override
public void run() {
query.removeEventListener(listener);
listenerRemovePending = false;
Log.d(LOG_TAG, "run");
}
};
#Override
protected void onActive() {
super.onActive();
if (listenerRemovePending) {
handler.removeCallbacks(removeListener);
Log.d(LOG_TAG, "listenerRemovePending");
}
else {
query.addValueEventListener(listener);
Log.d(LOG_TAG, "addValueEventListener");
}
listenerRemovePending = false;
Log.d(LOG_TAG, "listenerRemovePending");
}
#Override
protected void onInactive() {
super.onInactive();
// Listener removal is schedule on a two second delay
handler.postDelayed(removeListener, 4000);
listenerRemovePending = true;
Log.d(LOG_TAG, "listenerRemovePending");
}
private class MyValueEventListener implements ValueEventListener {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
setValue(dataSnapshot);
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.e(LOG_TAG, "Can't listen to query " + query, databaseError.toException());
}
}
}
I have xamarin. form app of few views, one among those views has a title of 42 characters. Is there any way to get that displayed on view without missing any character. When I try this renderer I am getting font size applicable for every view but I need to display that for the only specific view which has a title of 42 characters.
[assembly: ExportRenderer(typeof(CustomNavigationPageControl), typeof(CustomNavigationPageRenderer))]
namespace ALCInspection.Droid.Dependecies
{
public class CustomNavigationPageRenderer : NavigationPageRenderer
{
public CustomNavigationPageRenderer(Context context) : base(context)
{
}
private Android.Support.V7.Widget.Toolbar _toolbar;
private Android.Support.V7.Widget.Toolbar toolbar;
public override void OnViewAdded(Android.Views.View child)
{
base.OnViewAdded(child);
if (child.GetType() == typeof(Android.Support.V7.Widget.Toolbar))
{
toolbar = child as Android.Support.V7.Widget.Toolbar;
toolbar.ChildViewAdded += Toolbar_ChildViewAdded;
var a = toolbar.ChildCount;
}
}
void Toolbar_ChildViewAdded(object sender, ChildViewAddedEventArgs e)
{
var view = e.Child.GetType();
if (e.Child.GetType() == typeof(Android.Support.V7.Widget.AppCompatTextView))
{
var textView = e.Child as Android.Support.V7.Widget.AppCompatTextView;
textView.TextSize = 16;
toolbar.ChildViewAdded -= Toolbar_ChildViewAdded;
}
}
}
}
public class CustomNavigationPageControl : NavigationPage
{
public CustomNavigationPageControl(Page root) : base(root)
{
}
}
public static async Task NavigateToAsyncToSmallTitleView(Page firstPageToNavigate, INavigation navigation = null)
{
try
{
if (navigation == null)
{
navigation = ((CustomNavigationPageControl)Application.Current.MainPage).Navigation;
}
await navigation.PushAsync(firstPageToNavigate, false);
}
catch(Exception exception)//exception specified cast is not valid
{
}
}
and i am calling it as
await Helper.NavigateToAsyncWithSmallTitle(new OtherViwq());
I come with above code on searching but it is throwing specified cast exception.
According to this question, you need to use a custom renderer.
Have a look also at here, duplicate question here and here.
Hope it helps..
I'm working on a project in android for a udacity course I'm currently trying to implement a search function while adhering to android architecture components and using firestore and room I'm fairly new to all these concepts so please point out anything that seems wrong.
So I made a database repository to keep my firestore and room databases in sync and to deliver the data. I'm then using viewmodel and the observer pattern (I think) so my observer gets the data and looks for changes gives it to my adapter (refreshMyList(List)) which populates a recyclerview like this :
contactViewModel = ViewModelProviders.of(this).get(ContactsViewModel.class);
contactViewModel.getAllContacts().observe(this, new
Observer<List<DatabaseContacts>>() {
#Override
public void onChanged(#Nullable List<DatabaseContacts>
databaseContacts) {
ArrayList<DatabaseContacts> tempList = new ArrayList<>();
tempList.addAll(databaseContacts);
contactsAdapter.refreshMyList(tempList);
if (tempList.size() < 1) {
results.setVisibility(View.VISIBLE);
} else {
results.setVisibility(View.GONE);
}
}
});
I now want to perform a search of the data, I have my room queries all set up fine and I have methods in my data repository to get contacts based on a search string but I cant seem to refresh my list I've read that there are ways to do it like Transformations.switchMap ? but i cant seem to wrap my head around how it works can anyone help me
Currently I'm trying to return a List of results from an async task, it used to return live data but I changed it as getValue() was always null, not sure if that's correct, heres the async :
private static class searchContactByName extends AsyncTask<String, Void,
ArrayList<DatabaseContacts>> {
private LiveDatabaseContactsDao mDao;
searchContactByName(LiveDatabaseContactsDao dao){
this.mDao = dao;
}
#Override
protected ArrayList<DatabaseContacts> doInBackground(String... params) {
ArrayList<DatabaseContacts> contactsArrayList = new ArrayList<>();
mDao.findByName("%" + params[0] + "%");
return contactsArrayList;
}
}
I call this from my contacts repository in its own sort of wrapper :
public List<DatabaseContacts> getContactByName(String name) throws
ExecutionException, InterruptedException {
//return databaseContactsDao.findByName(name);
return new searchContactByName(databaseContactsDao).execute(name).get();
}
and this is called from my view model like this :
public List<DatabaseContacts> getContactByName(String name) throws
ExecutionException, InterruptedException {
return contactRepository.getContactByName(name);
}
I'm then calling this from my fragment :
private void searchDatabase(String searchString) throws ExecutionException,
InterruptedException {
List<DatabaseContacts> searchedContacts =
contactViewModel.getContactByName("%" + searchString + "%");
ArrayList<DatabaseContacts> contactsArrayList = new ArrayList<>();
if (searchedContacts != null){
contactsArrayList.addAll(searchedContacts);
contactsAdapter.refreshMyList(contactsArrayList);
}
}
and this is called from an on search query text changed method in my onCreateOptionsMenu :
#Override
public boolean onQueryTextChange(String newText) {
try {
searchDatabase(newText);
} catch (ExecutionException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
return false;
}
but it just does nothing my original recyclerview contents never change any ideas?
you can use Transformation.switchMap to do search operations.
In viewmodel create MutableLiveData which has latest search string.
Inside viewmodel use:
LiveData<Data> data =
LiveDataTransformations.switchMap(searchStringLiveData, string ->
repo.loadData(string)))
Return the above live data to activity so it can observe and update view.
I faced the same issue and I managed to fix it using
switchMap
and
MutableLiveData
We just need to use MutableLiveData to set the current value of editText, and when the user search we call setValue(editText.getText())
public class FavoriteViewModel extends ViewModel {
public LiveData<PagedList<TeamObject>> teamAllList;
public MutableLiveData<String> filterTextAll = new MutableLiveData<>();
public void initAllTeams(TeamDao teamDao) {
this.teamDao = teamDao;
PagedList.Config config = (new PagedList.Config.Builder())
.setPageSize(10)
.build();
teamAllList = Transformations.switchMap(filterTextAll, input -> {
if (input == null || input.equals("") || input.equals("%%")) {
//check if the current value is empty load all data else search
return new LivePagedListBuilder<>(
teamDao.loadAllTeam(), config)
.build();
} else {
System.out.println("CURRENTINPUT: " + input);
return new LivePagedListBuilder<>(
teamDao.loadAllTeamByName(input), config)
.build();
}
});
}
}
in Activity of fragment
viewModel = ViewModelProviders.of(activity).get(FavoriteViewModel.class);
viewModel.initAllTeams(AppDatabase.getInstance(activity).teamDao());
FavoritePageListAdapter adapter = new FavoritePageListAdapter(activity);
viewModel.teamAllList.observe(
activity, pagedList -> {
try {
Log.e("Paging ", "PageAll" + pagedList.size());
try {
//to prevent animation recyclerview when change the list
recycleFavourite.setItemAnimator(null);
((SimpleItemAnimator) Objects.requireNonNull(recycleFavourite.getItemAnimator())).setSupportsChangeAnimations(false);
} catch (Exception e) {
}
adapter.submitList(pagedList);
} catch (Exception e) {
}
});
recycleFavourite.setAdapter(adapter);
//first time set an empty value to get all data
viewModel.filterTextAll.setValue("");
edtSearchFavourite.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
#Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
#Override
public void afterTextChanged(Editable editable) {
//just set the current value to search.
viewModel.filterTextAll.setValue("%" + editable.toString() + "%");
}
});
Room Dao
#Dao
public interface TeamDao {
#Query("SELECT * FROM teams order by orders")
DataSource.Factory<Integer, TeamObject> loadAllTeam();
#Query("SELECT * FROM teams where team_name LIKE :name or LOWER(team_name_en) like LOWER(:name) order by orders")
DataSource.Factory<Integer, TeamObject> loadAllTeamByName(String name);
}
PageListAdapter
public class FavoritePageListAdapter extends PagedListAdapter<TeamObject, FavoritePageListAdapter.OrderHolder> {
private static DiffUtil.ItemCallback<TeamObject> DIFF_CALLBACK =
new DiffUtil.ItemCallback<TeamObject>() {
// TeamObject details may have changed if reloaded from the database,
// but ID is fixed.
#Override
public boolean areItemsTheSame(TeamObject oldTeamObject, TeamObject newTeamObject) {
System.out.println("GGGGGGGGGGGOTHERE1: " + (oldTeamObject.getTeam_id() == newTeamObject.getTeam_id()));
return oldTeamObject.getTeam_id() == newTeamObject.getTeam_id();
}
#Override
public boolean areContentsTheSame(TeamObject oldTeamObject,
#NonNull TeamObject newTeamObject) {
System.out.println("GGGGGGGGGGGOTHERE2: " + (oldTeamObject.equals(newTeamObject)));
return oldTeamObject.equals(newTeamObject);
}
};
private Activity activity;
public FavoritePageListAdapter() {
super(DIFF_CALLBACK);
}
public FavoritePageListAdapter(Activity ac) {
super(DIFF_CALLBACK);
this.activity = ac;
}
#NonNull
#Override
public OrderHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_favourite, parent, false);
return new FavoritePageListAdapter.OrderHolder(view);
}
#Override
public void onBindViewHolder(#NonNull OrderHolder holder,
int position) {
System.out.println("GGGGGGGGGGGOTHERE!!!");
if (position <= -1) {
return;
}
TeamObject teamObject = getItem(position);
try {
holder.txvTeamRowFavourite.setText(teamObject.getTeam_name());
} catch (Exception e) {
e.printStackTrace();
}
}
public class OrderHolder extends RecyclerView.ViewHolder {
private TextView txvTeamRowFavourite;
OrderHolder(View itemView) {
super(itemView);
txvTeamRowFavourite = itemView.findViewById(R.id.txv_team_row_favourite);
}
}
}
Here is a working example in KOTLIN
in the Fragment
binding.search.addTextChangedListener { text ->
viewModel.searchNameChanged(text.toString())
}
viewModel.customers.observe(this, Observer {
adapter.submitList(it)
binding.swipe.isRefreshing=false
})
search -> is my edit text
customers -> is the data list in the viewModel
View Model
private val _searchStringLiveData = MutableLiveData<String>()
val customers = Transformations.switchMap(_searchStringLiveData){string->
repository.getCustomerByName(string)
}
init {
refreshCustomers()
_searchStringLiveData.value=""
}
fun searchNameChanged(name:String){
_searchStringLiveData.value=name
}
I faced the same issue and solved it with the answer of #Rohit, thanks! I simplified my solution a bit to illustrate it better. There are Categories and each Category has many Items. The LiveData should only return items from one Category. The user can change the Category and then the fun search(id: Int) is called, which changes the value of a MutableLiveData called currentCategory. This then triggers the switchMap and results in a new query for items of the category:
class YourViewModel: ViewModel() {
// stores the current Category
val currentCategory: MutableLiveData<Category> = MutableLiveData()
// the magic happens here, every time the value of the currentCategory changes, getItemByCategoryID is called as well and returns a LiveData<Item>
val items: LiveData<List<Item>> = Transformations.switchMap(currentCategory) { category ->
// queries the database for a new list of items of the new category wrapped into a LiveData<Item>
itemDao.getItemByCategoryID(category.id)
}
init {
currentCategory.value = getStartCategoryFromSomewhere()
}
fun search(id: Int) { // is called by the fragment when you want to change the category. This can also be a search String...
currentCategory.value?.let { current ->
// sets a Category as the new value of the MutableLiveData
current.value = getNewCategoryByIdFromSomeWhereElse(id)
}
}
}
I implement the bar code searching product using the following approach.
Everytime the value of productBarCode changes, the product will be searched in the room db.
#AppScoped
class PosMainViewModel #Inject constructor(
var localProductRepository: LocalProductRepository) : ViewModel() {
val productBarCode: MutableLiveData<String> = MutableLiveData()
val product: LiveData<LocalProduct> = Transformations.switchMap(productBarCode) { barcode ->
localProductRepository.getProductByBarCode(barcode)
}
init {
productBarCode.value = ""
}
fun search(barcode: String) {
productBarCode.value = barcode
}}
In activity
posViewModel.product.observe(this, Observer {
if (it == null) {
// not found
} else {
productList.add(it)
rvProductList.adapter!!.notifyDataSetChanged()
}
})
for searching
posViewModel.search(barcode) //search param or barcode
The goal is to display dialog for user to select date on tap on EditText.
I'm truing to implement binding that will show dialog on click. The code is the following:
public class EditDateBinding : BindingWrapper<EditText, DateTime>
{
public EditDateBinding(EditText androidControl) : base(androidControl)
{
}
public override void SubscribeToEvents()
{
Target.Click += InputClick;
}
private void InputClick(object sender, EventArgs args)
{
DateTime parsedDate = DateTime.Now;
DateTime.TryParse(Target.Text, CultureInfo.CurrentCulture, DateTimeStyles.None, out parsedDate);
var dialog = new DatePickerDialogFragment(Target.Context, parsedDate, OnDateSet);
dialog.Show(
// Can't get fragment manager here
, "date");
}
private void OnDateSet(object sender, DatePickerDialog.DateSetEventArgs e)
{
SetValueToView(Target, e.Date);
}
protected override void Dispose(bool isDisposing)
{
base.Dispose(isDisposing);
if (isDisposing)
{
if (Target != null)
{
Target.Click -= InputClick;
}
}
}
protected override void SetValueToView(EditText androidControl, DateTime value)
{
androidControl.Text = value.ToShortDateString();
}
}
But I cant find a way to get FragmentManager instance in order to call Show method of instantiated dialog. Can this be implemented in any way?
Found a way to implement it:
var act = (Activity) Target.Context;
dialog.Show(act.FragmentManager, "date");
Little problem with my Android application and I don't know how to solve it with MVVM Cross.
Here is my ViewModel:
public class AddressesShowViewModel : MvxViewModel
{
public List<Address> Addresses { get; set; }
public AddressesShowViewModel(string addressesForListView)
{
Addresses = JsonConvert.DeserializeObject<List<Address>>(addressesForListView);
}
public IMvxCommand ShowItemCommand
{
get
{
//return new MvxRelayCommand<Type>((type) => this.RequestNavigate(type));
return new MvxRelayCommand(DoShowContact);
}
}
private Address selectedItem;
public Address SelectedItem
{
get { return selectedItem; }
set { selectedItem = value; FirePropertyChanged(() => SelectedItem); }
}
private void DoShowContact()
{
RequestNavigate<AddressShowViewModel>();
}
}
My AddressesShow.axml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:local="http://schemas.android.com/apk/res/INMobileCRM4Android.INMobileCRM4Android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Mvx.MvxBindableListView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
local:MvxBind="{'ItemsSource':{'Path':'Addresses'},'ItemClick':{'Path':'ShowItemCommand'}, 'SelectedItem':{'Path':'SelectedItem'}}"
local:MvxItemTemplate="#layout/addresslistitem"
/>
</FrameLayout>
I would like to know, how I can get the SelectedItem from the ListView in AddressesShow.axml.. I tried to create a Property 'SelectedItem'.. But its getting called at the beginning, when the ViewModel is created (and is obviously returning null), not when the Item is clicked.. Its btw a type of Address, not just a String or something.. Maybe any suggestions?
The lack of SelectedItem in Droid was identified as an issue last week during preparation for Daniel's talk at Build.
To workaround it, there were a couple of quick answers:
1 There is SelectedItemPosition you can use for binding - this is an int
2 You can use a Click ICommand/IMvxCommand binding instead of using SelectedItem - in your example, this would be the same axml but
public IMvxCommand ShowItemCommand
{
get
{
return new MvxRelayCommand<Address>(address => DoShowContact(address));
}
}
To be clear this Click option above is what I would use.
If SelectedItem really is needed...
Then for a complete answer, Daniel and I prototyped a new binding. This binding was registered using:
registry.RegisterFactory(new MvxCustomBindingFactory<MvxBindableListView>("SelectedItem", adapterView => new MvxAdapterViewSelectedItemTargetBinding(adapterView)));
and contained the logic:
using System;
using Android.Widget;
using Cirrious.MvvmCross.Binding.Droid.Views;
using Cirrious.MvvmCross.Binding.Interfaces;
using Cirrious.MvvmCross.Interfaces.Platform.Diagnostics;
namespace Cirrious.MvvmCross.Binding.Droid.Target
{
#warning This needs to be redone for all adapterviews not just list view!
#warning The use of ItemClick instead of ItemSelected needs to be reinvestigated here!
public class MvxAdapterViewSelectedItemTargetBinding : MvxBaseAndroidTargetBinding
{
private readonly MvxBindableListView _view;
private object _currentValue;
public MvxAdapterViewSelectedItemTargetBinding(MvxBindableListView view)
{
_view = view;
((ListView)_view).ItemClick += OnItemClick;
}
private void OnItemClick(object sender, AdapterView.ItemClickEventArgs itemClickEventArgs)
{
var container = (_view.GetItemAtPosition(itemClickEventArgs.Position) as MvxJavaContainer);
if (container == null)
{
MvxBindingTrace.Trace(MvxTraceLevel.Warning, "Missing MvxJavaContainer in MvxAdapterViewSelectedItemTargetBinding");
return;
}
var newValue = container.Object;
if (!newValue.Equals(_currentValue))
{
_currentValue = newValue;
FireValueChanged(newValue);
}
}
public override void SetValue(object value)
{
#warning Sort out Equals test here
if (value != null && value != _currentValue)
{
var index = _view.Adapter.GetPosition(value);
if (index < 0)
{
MvxBindingTrace.Trace(MvxTraceLevel.Warning, "Value not found for spinner {0}", value.ToString());
return;
}
_currentValue = value;
_view.SetSelection(index);
}
}
public override MvxBindingMode DefaultMode
{
get { return MvxBindingMode.TwoWay; }
}
public override Type TargetType
{
get { return typeof(object); }
}
protected override void Dispose(bool isDisposing)
{
if (isDisposing)
{
((ListView)_view).ItemClick -= OnItemClick;
}
base.Dispose(isDisposing);
}
}
}
To test this worked, I used the Tutorial PullToRefresh code adapted using:
<Mvx.MvxBindableListView android:id="#android:id/list" android:layout_width="fill_parent"
android:layout_height="fill_parent"
local:MvxBind="{'ItemsSource':{'Path':'Emails'},'ItemClick':{'Path':'ShowItemCommand'},'SelectedItem':{'Path':'TheSelectedEmail'}}"
local:MvxItemTemplate="#layout/listitem_email"
/>
and:
public class SimpleEmail
{
public string From { get; set; }
public string Header { get; set; }
public string Message { get; set; }
}
private ObservableCollection<SimpleEmail> _emails;
public ObservableCollection<SimpleEmail> Emails
{
get { return _emails; }
private set { _emails = value; RaisePropertyChanged(() => Emails); }
}
private SimpleEmail _email;
public SimpleEmail TheSelectedEmail
{
get { return _email; }
set
{
_email = value;
MvxTrace.Trace(MvxTraceLevel.Error, "HELLO {0} ", value == null ? "null" : value.From);
}
}
One thing to be careful about in all this work is that a listview selected item in Android is slightly different to a listbox selected item in Silverlight/wp - e.g. it can be quite hard to get a listview in android to highlight the current selection and it can be quite hard to get the listview to generate selection changed events.
Note: I've logged an issue on Droid SelectedItem to https://github.com/slodge/MvvmCross/issues/52 - I'll make sure the binding is added to the core library in the near future