If in WPF a decorative element is implemented using the abstract class Adorner, then how to achieve the implementation of this object in Avalonia UI?
//code wpf
public class ControlAdorner: Adorner
{
public ControlAdorner(UIElement adornedElement) : base(adornedElement)
{
}
protected override void OnRender(DrawingContext drawingContext)
{
Rect adornedElementRect = new Rect(this.AdornedElement.DesiredSize);
... some code ...
}
}
There is AdornerLayer class with attached property AdornedElement.
I haven't tested code below, but it should work.
var adornerElement = yourElement;
var adornerLayer = AdornerLayer.GetAdornerLayer(adornerElement);
if (adornerLayer != null)
{
var adornedElement = new Border();
adornerLayer.Children.Add(adornedElement);
AdornerLayer.SetAdornedElement(adornedElement, adornerElement);
}
Related
I'm currently refactoring a few abstraction layers into a Xamarin app in order to break the "monolithic" structure left by the previous dev, but something has gone awry. In my ViewModel, I have a few properties that call NotifyPropertyChange in order to update the UI whenever a value is picked from a list. Like so:
public Notifier : BindableObject, INotifyPropertyChanged
{
//...
protected void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Had to create a middle layer due to my specific needs
public interface ISomeArea
{
DefinicaoServicoMobile TipoPasseio { get; set; }
}
-
public class SomeAreaImpl : Notifier, ISomeArea
{
//...
protected DefinicaoServicoMobile _tipoPasseio;
public DefinicaoServicoMobile TipoPasseio
{
get => _tipoPasseio;
set
{
if (_tipoPasseio != value)
{
_tipoPasseio = value;
NotifyPropertyChanged(nameof(TipoPasseio));
}
}
}
}
The actual bound view model:
public MyViewModel : BaseViewModel, ISomeArea
{
private SomeAreaImpl someArea;
//...
public MyViewModel()
{
// This is meant to provide interchangable areas across view models with minimal code replication
someArea = new SomeAreaImpl();
}
public DefinicaoServicoMobile TipoPasseio
{
get => someArea.TipoPasseio;
set => someArea.TipoPasseio = value;
}
}
And the .xaml snippet:
<renderers:Entry
x:Name="TxtTipoPasseio"
VerticalOptions="Center"
HeightRequest="60"
HorizontalOptions="FillAndExpand"
Text="{Binding TipoPasseio.DsPadrao}"
/>
The renderer opens a list allowing the user to choose whichever "TipoPasseio" they want, and supposedly fill the textbox with a DsPadrao (standard description). Everything works, even the reference to TipoPasseio is held after being selected (I know this because should I bring up the list a second time, it will only display the selected DsPadrao, giving the user the option to clean it. If he does, a third tap will show all the options again.
I might have screwed up in the abstraction, as I don't see the setter for myViewModel.TipoPasseio being called, tbh
Any ideas?
Let's reason through what Xamarin knows (as best as we can, since you didn't include all of the relevant code):
You have a data context having the type MyViewModel
That view model object has a property named TipoPasseio, having type DefinicaoServicoMobile
The type DefinicaoServicoMobile has a property named DsPadrao
It is that last property that is bound to the Entry.Text property.
In a binding, any observable changes to values forming the source or path for the binding will cause the runtime to update the target property for the binding (Entry.Text) and thus result in a change in the visual appearance (i.e. new text being displayed).
Note the key word observable. Here are the things I see which are observable by Xamarin:
The data context. But this doesn't change.
That's it.
With respect to the value of the MyViewModel.TipoPasseio property, there's nothing in the code you posted showing this property changing. But if it did, it doesn't look like MyViewModel implements INotifyPropertyChanged, so Xamarin wouldn't have a way to observe such a change.
On that second point, you do implement INotifyPropertyChanged in the SomeAreaImpl type. But Xamarin doesn't know anything about that object. It has no reference to it, and so has no way to subscribe to its PropertyChanged event.
Based on your statement:
I don't see the setter for myViewModel.TipoPasseio being called
That suggests that the TipoPasseio property isn't being changed. I.e. while you wouldn't be providing notification to Xamarin even if it did change, it's not changing anyway.
One property that does seem to be changing is the DsPadrao property (after all, it's the property that's actually providing the value for the binding). And while you don't provide enough details for us to know for sure, it seems like a reasonable guess that the DefinicaoServicoMobile doesn't implement INotifyPropertyChanged, and so there's no way for Xamarin to ever find out the value of that property might have changed either.
In other words, of all the things that Xamarin can see, the only one that it would be notified about of a change is the data context. And that doesn't seem to be what's changing in your scenario. None of the other values are held by properties backed by INotifyPropertyChanged.
Without a complete code example, it's impossible to know for sure what the right fix is. Depending on what's changing and how though, you need to implement INotifyPropertyChanged for one or more of your types that don't currently do so.
As it turns out, I wasn't firing the NotifyPropertyChanged of the correct object. Both MyViewModel and SomeAreaImpl implemented INotifyPropertyChanged per the Notifier class as BaseViewModel also extends from Notifier but that ended up ommited in my question. Having figured that out, here's an working (and complete) example:
public Notifier : BindableObject, INotifyPropertyChanged
{
//...
protected void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Specifics about DefinicaoServicoMobile are negligible to this issue
public interface ISomeArea
{
//...
DefinicaoServicoMobile TipoPasseio { get; set; }
Task SetServico(ServicoMobile servicoAtual;
//...
}
For the sake of clarification
public abstract class BaseViewModel : Notifier
{
protected abstract Task SetServico(ServicoMobile servicoAtual);
public async Task SetServico()
{
//...
await SetServico(servicoAtual);
//...
}
}
Changed a couple of things here. It no longer extends from Notifier, which was kinda weird to begin with. Also this is where I assign TipoPasseio
public class SomeAreaImpl : ISomeArea
{
//...
protected DefinicaoServicoMobile _tipoPasseio;
// I need to call the viewModel's Notifier, as this is the bound object
private BaseViewModel viewModel;
public AreaServicosDependentesImpl(BaseViewModel viewModel)
{
this.viewModel = viewModel;
}
public DefinicaoServicoMobile TipoPasseio
{
get => _tipoPasseio;
set
{
if (_tipoPasseio != value)
{
_tipoPasseio = value;
viewModel.NotifyPropertyChanged(nameof(TipoPasseio));
}
}
}
//Assigning to the property
public async Task SetServico(ServicoMobile servicoAtual, List<DefinicaoServicoMobile> listDefinicaoServico)
{
//...
TipoPasseio = listDefinicaoServico
.FirstOrDefault(x => x.CdServico == servicoAtual.TpPasseio.Value);
//...
}
}
Changes to the view model:
public MyViewModel : BaseViewModel, ISomeArea
{
private SomeAreaImpl someArea;
//...
public MyViewModel()
{
someArea = new SomeAreaImpl(this);
}
public DefinicaoServicoMobile TipoPasseio
{
get => someArea.TipoPasseio;
set => someArea.TipoPasseio = value;
}
protected override async Task SetServico(ServicoMobile servicoAtual)
{
//...
someArea.SetServico(servicoAtual, ListDefinicaoServico.ToList());
//...
}
}
View model binding
public abstract class BaseEncerrarPontoRotaPage : BasePage
{
private Type viewModelRuntimeType;
public BaseEncerrarPontoRotaPage(Type viewModelRuntimeType)
{
this.viewModelRuntimeType = viewModelRuntimeType;
}
private async Task BindContext(PontoRotaMobile pontoRota, ServicoMovelMobile servicoMovel, bool finalizar)
{
_viewModel = (BaseViewModel)Activator.CreateInstance(viewModelRuntimeType, new object[] { pontoRota, UserDialogs.Instance });
//...
await _viewModel.SetServico();
//...
BindingContext = _viewModel;
}
public static BaseEncerrarPontoRotaPage Create(EnumAcaoServicoType enumType)
{
Type pageType = enumType.GetCustomAttribute<EnumAcaoServicoType, PageRuntimeTypeAttribute>();
Type viewModelType = enumType.GetCustomAttribute<EnumAcaoServicoType, ViewModelRuntimeTypeAttribute>();
return (BaseEncerrarPontoRotaPage)Activator.CreateInstance(pageType, new object[] { viewModelType });
}
}
Page instantiation is performed in some other view model, not related to the structure presented here
private async Task ShowEdit(bool finalizar)
{
await Task.Run(async () =>
{
var idAcaoServico = ServicoMobileAtual.DefinicaoServicoMobile.IdAcaoServico;
var page = BaseEncerrarPontoRotaPage.Create((EnumAcaoServicoType)idAcaoServico);
await page.BindContext(PontoRotaAtual, ServicoMovelMobileAtual, finalizar);
BeginInvokeOnMainThread(async () =>
{
await App.Navigation.PushAsync(page);
});
});
}
Codebehind:
public partial class MyPage : BaseEncerrarPontoRotaPage
{
public NormalUnidadePage() { }
public MyPage(Type viewModelType) : base(viewModelType)
{
InitializeComponent();
//Subscription to show the list
TxtTipoPasseio.Focused += TxtTipoPasseio_OnFocused;
//...
}
}
XAML
<views:BaseEncerrarPontoRotaPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:views="clr-namespace:My.Name.Space.;assembly=Phoenix.AS"
x:Class="My.Name.Space.MyPage">
//...
<renderers:Entry
x:Name="TxtTipoPasseio"
VerticalOptions="Center"
HeightRequest="60"
HorizontalOptions="FillAndExpand"
Text="{Binding TipoPasseio.DsPadrao}"/>
//...
</views:BaseEncerrarPontoRotaPage>
I know could propagate an event from the AreaImpl classes in order to fire the Notify event in the view model, but right now I'm satisfied with this solution.
I have following react native component in android.
parent class contains some common settings,
and some template code (eg. setData).
android version
parent component
public abstract class ParentComponent<T extends Chart, U extends Entry> extends SimpleViewManager {
#ReactProp(name = "commonSettings")
public void setCommonSettings(T chart, ReadableMap propMap) {
// do common settings
}
abstract U createEntry(ReadableMap value);
#ReactProp(name = "data")
public void setData(Chart chart, ReadableArray values) {
for (int i = 0; i < values(); i++) {
chart.addEntry(values.getMap(i));
}
}
}
child component A
public class FooComponent extends ParentComponent<FooChart, FooEntry> {
#Override
public String getName() {
return "FooChart";
}
#Override
protected View createViewInstance(ThemedReactContext reactContext) {
return new FooChart(reactContext);
}
#ReactProp(name = "fooSettings")
public void setFooSettings(FooChart chart, ReadableMap propMap) {
// do foo settings
}
#Override
FooEntry createEntry(ReadableMap value) {
return xxxxx;
}
}
child component B
public class BarComponent extends ParentComponent<BarChart, BarEntry> {
#Override
public String getName() {
return "BarChart";
}
#Override
protected View createViewInstance(ThemedReactContext reactContext) {
return new BarChart(reactContext);
}
#ReactProp(name = "barSettings")
public void setBarSettings(FooChart chart, ReadableMap propMap) {
// do foo settings
}
#Override
BarEntry createEntry(ReadableMap value) {
return xxxxx;
}
}
But How should I implement these in ios?
I am quite new to oc & swift developing, here are my doubts.
In ios, there need a RCTViewManager that return a UIView instance.
what shoud be the UIView instance?
I don't want to inherit FooChart & BarChart, delegate is what I need.
So should I create a custom UIView, initialize a fooChart and holds its reference, then self.addSubView(fooChart) ?
How to share the common settings and template code? Extension ?
Do I have to duplicate RCT_EXPORT_VIEW_PROPERTY(commonSettings, NSDictionary) in both FooChartViewManager and BarChartViewManager?
I tried to define class ParentComponentManagerSwift: RCTViewManager,
and declare RCT_EXPORT_VIEW_PROPERTY(commonSettings, NSDictionary) there,
and class FooComponentManagerSwift: ParentComponentManager, but it doesn't work.
But our components do inherit bunch of exports like backgroundColor/width/height which declared in RCTViewManager?
1) If FooChart & BarChart is a subclass of UIView, then you can initialize FooChart & BarChart, set delegate and return it directly
- (UIView *)view {
FooChart *chart = [FooChart new];
chart.delegate = self;
return chart;
}
2) You can share common settings and template code using inheritance
3) You can either duplicate exports or create some macros that will combine common exports.
Components actually do not inherit exports. All components have RCTViewManager exports + own exports, but its done without using inheritance.
I am having one Application based on XamarinForms.
One background service I have created in Android project and that service would like to send data to ContentPage(which is in PCL) which is displayed to user.
How could I pass data to ContentPage(From xx.Droid project to PCL)?
One solution is:
To Create class in PCL with static variable(e.g. var TEMP_VAR), which will be accessed from xxx.Droid project.
Update value of that static variable(TEMP_VAR) from the service class from the xxx.Droid project.
Need to create Notifier on that static variable(TEMP_VAR)
Update the content page using MessageCenter Mechanism if require.
If there is any better solution, could you please provide me?
This can be achieved using the concept of C#
Dependency service
Event
Need to have 4 classes for such an implementation:
Interface in PCL(e.g. CurrentLocationService.cs) with event handlers defined in it.
namespace NAMESPACE
{
public interface CurrentLocationService
{
void start();
event EventHandler<PositionEventArgs> positionChanged;
}
}
Implementation of interface of PCL in xxx.Droid project (e.g. CurrentLocationService_Android.cs) using Dependency service
class CurrentLocationService_Android : CurrentLocationService
{
public static CurrentLocationService_Android mySelf;
public event EventHandler<PositionEventArgs> positionChanged;
public void start()
{
mySelf = this;
Forms.Context.StartService(new Intent(Forms.Context, typeof(MyService)));
}
public void receivedNewPosition(CustomPosition pos)
{
positionChanged(this, new PositionEventArgs(pos));
}
}
ContentPage in PCL - which will have object of implementation of interface.
Object can be obtained by
public CurrentLocationService LocationService
{
get
{
if(currentLocationService == null)
{
currentLocationService = DependencyService.Get<CurrentLocationService>();
currentLocationService.positionChanged += OnPositionChange;
}
return currentLocationService;
}
}
private void OnPositionChange(object sender, PositionEventArgs e)
{
Debug.WriteLine("Got the update in ContentPage from service ");
}
Background service in xxx.Droid project. This service will have reference of implementation of dependency service CurrentLocationService.cs
[Service]
public class MyService : Service
{
public string TAG = "MyService";
public override IBinder OnBind(Intent intent)
{
throw new NotImplementedException();
}
public override StartCommandResult OnStartCommand(Android.Content.Intent intent, StartCommandFlags flags, int startId)
{
Log.Debug(TAG, TAG + " started");
doWork();
return StartCommandResult.Sticky;
}
public void doWork()
{
var t = new Thread(
() =>
{
Log.Debug(TAG, "Doing work");
Thread.Sleep(10000);
Log.Debug(TAG, "Work completed");
if(CurrentLocationService_Android.mySelf != null)
{
CustomPosition pos = new CustomPosition();
pos.update = "Finally value is updated";
CurrentLocationService_Android.mySelf.receivedNewPosition(pos);
}
StopSelf();
});
t.Start();
}
}
Note : PositionEventArgs class need to be created as per usage to pass on data between service and ContentPage.
This works for me like charm.
Hope so this would be helpful to you.
I would to override constroller constrcuter's like this :
class XControler extends AppController {
public $attr = null;
public __construct(){
$this->attr = new YController();
}
}
But when I do that I take error ! can you explain me why and how I do that with out using requestAction just OOP !
thanks
Controllers are responsible for dealing with end user requests. Each controller action should have a view, and normally you would not want to access the methods from YController inside XController.
What you want to achieve can be done this way:
XController.php
App::uses('YController', 'Controller');
class XController extends AppController {
public $attr;
public $uses = array('Person');
public function __construct($request = null, $response = null) {
$this->attr = new YController();
parent::__construct($request, $response);
}
public function method1() {
// you can now call methods from YController:
$this->attr->Ymethod1();
}
}
YController.php
class YController extends AppController {
public function Ymethod1() {
// ....
}
}
However, the business logic should be inside Models or Components. This is the proper way to share methods between more controllers.
So your XController should look like:
class XController extends AppController {
public $uses = array('Model1');
public function action1() {
$this->Model1->method1();
// ....
}
}
I'm trying to make DataContract Serializer work with one of my class.
Here it is :
public class MyOwnObservableCollection<T> : ObservableCollection<T>, IDisposable
where T : IObjectWithChangeTracker, INotifyPropertyChanged
{
protected List<T> removedItems;
[DataMember]
public List<T> RemovedItems
{
get { return this.removedItems;}
set { this.removedItems = value;}
}
// Other code removed for simplification
// ...
//
}
It is important to understand that the RemovedItems list gets populated automatically when you remove an Item from the ObservableCollection.
Now serializing an instance of this class using the DataContractSerializer with one element in the removedItems list with the following code :
MyOwnObservableCollection<Test> _Test = new MyOwnObservableCollection<Test>();
DataContractSerializer dcs = new DataContractSerializer(typeof(MyOwnObservableCollection<Test>));
XmlWriterSettings settings = new XmlWriterSettings() { Indent = true };
string fileName = #"Test.xml";
Insurance atest = new Test();
atest.Name = #"sfdsfsdfsff";
_Test.Add(atest);
_Test.RemoveAt(0); // The Iitem in the ObservableCollection is moved to the RemovedItems List/
using (var w = XmlWriter.Create(fileName, settings))
{
dcs.WriteObject(w, _Test);
}
ends with nothing in the XML file :
<?xml version="1.0" encoding="utf-8"?>
<ArrayOfTest xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="MyNameSpace" />
Why is this public property ignored ? What have I missed here ?
TIA.
The problem here is that your class is derived from a collection, and as such, the DataContractSerializer serializes only its items, but not any extra properties, as stated here: No properties when using CollectionDataContract.
A workaround would be using the original (inherited) collection as a property, rather than inheriting from it:
public class MyOwnObservableCollection<T> : IDisposable
where T : IObjectWithChangeTracker, INotifyPropertyChanged
{
readonly ObservableCollection<T> originalCollection = new ObservableCollection<T>();
protected List<T> removedItems = = new List<T>();
[DataMember]
public List<T> RemovedItems
{
get { return this.removedItems;}
set { this.removedItems = value;}
}
[DataMember]
public ObservableCollection<T> OriginalCollection
{
get { return this.originalCollection; }
}
// ...
}