请解释如何正确理解这个结构：
fun bind(
cardModel: CardModel, deleteFromCard: (CardModel) -> Unit,
moreCount: (CardModel) -> Unit, lessCount: (CardModel) -> Unit
)
据我所知，单位与java中的viod相同
lessCount 是什么意思：(CardModel) - 是创建一个方法，作为方法中的一个接受值，还是我误解了什么？
我需要在两个 ListBox 列中显示两个列表，但是通过 MVVM 模式它会是一行。我已经搜索了互联网，但还没有找到任何东西。我只是在学习，也许正因为如此我错过了一些东西，如果有人有机会解释，或者至少是某种例子，我会很高兴。
视图模型：
private List<string> _artists = new();
private List<string> _names = new();
private List<Song> _songs = new();
public List<string> Artists
{
get
{
return _artists;
}
set { _artists = value; OnProopertyChanged(); }
}
public List<string> Names
{
get
{
return _names;
}
set { _names = value; OnProopertyChanged(); }
}
public List<Song> Songs
{
get
{
return _songs;
}
set { _songs = value; OnProopertyChanged(); }
}
for (int counterForList = 1; counterForList < 41; counterForList++)
{
HtmlMethod(counterForList,2, out Artist);
HtmlMethod(counterForList,3, out Name);
Song song = new Song(Name, Artist);
Songs.Add(song);
}
foreach (var song in Songs)
{
Artists.Add(song.Artist);
Names.Add(song.Name);
}
模型：
public class Song
{
public string Name { get; set; }
public string Artist { get; set; }
和 MainWindow 本身：
<Window xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="using:AvaloniaApplication1.ViewModels"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="600" d:DesignHeight="350"
x:Class="AvaloniaApplication1.Views.MainWindow"
Icon="/Assets/avalonia-logo.ico"
Title="AvaloniaApplication1"
Width="600"
Height="350">
<Design.DataContext>
<vm:MainWindowViewModel/>
</Design.DataContext>
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding Title}" HorizontalAlignment="Center" VerticalAlignment="Center" Grid.Column="1"/>
<ListBox Items="{Binding Songs}" Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="3" Grid.RowSpan="2">
<ListBox.ItemTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
</Grid>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
这里是代码，我不明白如何在不同的列中显示艺术家和名称，或者可以划分歌曲。在 avalonia 纪录片中写道，他们没有 ItemSource，他们只有一个 Item。
我使用库Microsoft.Toolkit.Mvvm，我ViewModel继承自ObservableObject（它有一个方法SetProperty。出于某种我不明白的原因，文档中的方法重载和现实有些不同，但即使是那些，也不可能重载。方法签名如下：
protected bool SetProperty<T> (T oldValue, T newValue, Action<T> callback, string? propertyName = default);
在视图模型中：
private bool _enableInbound;
public bool EnableInbound
{
get { return _enableInbound; }
set
{
SetProperty(ref _enableInbound, value, callback: new System.Action<bool>((target) =>
{
}));
}
}
但是，当您尝试使用它时，它会像这样出现在屏幕上。我尝试Action通过该方法，我也尝试只使用没有 的 lambda new Action，结果是一样的。可能是什么问题呢？
错误文字：Error CS1615 Argument 1 may not be passed with the 'ref' keyword
问题是将 ViewModel 的结果传递给任何 View
我的模特
struct ItemsModel: Codable {
var item1: String = ""
var item2: String = ""
}
看法
struct ContentView: View {
@ObservedObject var resultViewModel = CalcViewModel()
@State var isResultView: Bool = false
var body: some View {
NavigationView {
Form {
Section(header: Text("Ввод значения")) {
TextField("Введите число", text: $resultViewModel.itemModel.item1)
TextField("Введите число", text: $resultViewModel.itemModel.item2)
}
Section (header: Text("Ответ")) {
Text("\(resultViewModel.resultCalc())")
}
Button(action: {
self.isResultView.toggle()
}, label: {
Text("Рассчитать")
})
}
.sheet(isPresented: $isResultView) {
ResultView()
}
.navigationBarTitle(Text("Calculate"))
}
}
}
视图模型
class CalcViewModel: ObservableObject {
@Published var itemModel = ItemsModel()
var item1Double: Double {
return Double(itemModel.item1) ?? 0
}
var item2Double: Double {
return Double(itemModel.item2) ?? 0
}
func resultCalc() -> Double {
let resultDouble = item1Double + item2Double
print("👉 \(resultDouble)")
return resultDouble
}
}
查看将结果传递到哪里
struct ResultView: View {
@StateObject var vm = CalcViewModel()
var body: some View {
Text("Ответ: \(vm.resultCalc())")
}
}
我有一个带有 MVVM 和 Dagger 的应用程序。当我打开应用程序并加载列表时，我会在日志中看到服务器如何不断地请求列表。可能是什么问题呢？我的网络模块：
@Module(includes = [ViewModelModule::class])
class NetworkModule {
companion object {
const val KEY = "key"
const val BASE_URL = "base_url"
}
@Provides
@Singleton
fun provideOkHttp(): OkHttpClient {
val httpClient = OkHttpClient.Builder()
httpClient.addInterceptor(object : Interceptor {
@Throws(IOException::class)
override fun intercept(chain: Interceptor.Chain): okhttp3.Response {
val original = chain.request()
val originalHttpUrl = original.url
val url = originalHttpUrl.newBuilder()
//.addQueryParameter("apikey", KEY)
.build()
val requestBuilder = original.newBuilder()
.url(url)
.header("apikey", KEY)
val request = requestBuilder.build()
return chain.proceed(request)
}
})
// logging interceptor
val logging = HttpLoggingInterceptor()
logging.level = HttpLoggingInterceptor.Level.BODY
httpClient.addInterceptor(logging)
return httpClient.build()
}
@Provides
@Singleton
fun provideRetrofit(): Retrofit {
return Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(provideOkHttp())
.build()
}
@Provides
@Singleton
fun provideContactsService(retrofit: Retrofit) : ContactsService{
return retrofit.create(ContactsService::class.java)
}
}
视图模型：
class ContactsViewModel @Inject constructor(private val contactsRepository: ContactsRepository) :
ViewModel() {
var mutableLiveData = MutableLiveData<List<ContactsModel>>()
private val disposable = CompositeDisposable()
fun getContactMutableLiveData(): MutableLiveData<List<ContactsModel>> {
loadData()
return mutableLiveData
}
fun loadData() {
disposable.add(contactsRepository.modelSingle()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith(object : DisposableSingleObserver<List<ContactsModel>>() {
override fun onSuccess(t: List<ContactsModel>) {
getContactMutableLiveData().value = t
}
override fun onError(e: Throwable) {
}
})
)
}
}
订阅接收数据的活动部分：
contactsViewModel.getContactMutableLiveData().observe(this@ContactListActivity, Observer {
mAdapter = ContactsAdapter(this@ContactListActivity, it as ArrayList<ContactsModel>)
recycler_contacts.layoutManager =
LinearLayoutManager(applicationContext, OrientationHelper.VERTICAL, false)
recycler_contacts.adapter = mAdapter
recycler_contacts.setHasFixedSize(true)
mAdapter.sortByName()
})