您好我使用Xamarin.Forms创建了该应用程序 - 它在iOS中运行良好但当然它不适用于Android并且面临标题中提到的一些问题。
Lemme解释我的应用程序和代码继续，该应用程序有一个登录屏幕，并将在这个刚填充的列表视图及其单元格中使用导航移动到名为HomeController的主屏幕。虽然点击每一行会转到Master详细信息页面，但我收到错误，它在iOS而不是Android中正常工作。
App.cs
using System;
using Xamarin.Forms;
namespace eMO_Xamarin
{
public class App : Application
{
public App ()
{
// The root page of your application
var nav = new NavigationPage (new LoginViewController ());
nav.BarBackgroundColor = Color.FromHex("#EEEEEE");
nav.BarTextColor = Color.FromHex("#424242");
MainPage = nav;
}
}
}
LoginController.cs
using System;
using Xamarin.Forms;
using System.Collections.Generic;
namespace eMO_Xamarin
{
public class LoginViewController : ContentPage
{
Entry userEntry, passwordEntry;
public LoginViewController ()
{
NavigationPage.SetBackButtonTitle (this, "");
NavigationPage.SetHasBackButton (this, false);
this.BackgroundImage = "Bg1.jpg";
userEntry = new Entry () {
HorizontalOptions = LayoutOptions.FillAndExpand,
Placeholder = "Username"
};
passwordEntry = new Entry () {
HorizontalOptions = LayoutOptions.FillAndExpand,
Placeholder = "Password",
IsPassword = true
};
var loginButton = new Button () {
Text = "Login",
TextColor = Color.White,
BackgroundColor = Color.FromHex ("77D065")
};
loginButton.Clicked += OnButtonClickedLogin;
Title = "e-Loan";
this.Padding = new Thickness (50, Device.OnPlatform (20, 0, 0), 50, 20);
stack.Children.Add (appLogoImg);
stack.Children.Add (userEntry);
stack.Children.Add (passwordEntry);
stack.Children.Add (loginButton);
this.Content = scroll;
}
void OnButtonClickedLogin (object sender, EventArgs e)
{
Navigation.InsertPageBefore (new HomeViewController (), this);
Navigation.PopAsync ();
}
}
}
HomeController.cs
using System;
using System.Collections.Generic;
using Xamarin.Forms;
namespace eMO_Xamarin
{
public class HomeViewController : ContentPage
{
public HomeViewController ()
{
Title = "Welcome John!";
NavigationPage.SetBackButtonTitle (this, "Back");
NavigationPage.SetHasBackButton (this, false);
if (Device.Idiom == TargetIdiom.Phone) {
this.BackgroundImage = "login_home.jpg";
} else if (Device.Idiom == TargetIdiom.Tablet) {
this.BackgroundImage = "Bg6.jpg";
} else {
}
var toolbarItem = new ToolbarItem {
Text = "Logout"
};
toolbarItem.Clicked += OnLogoutButtonClicked;
ToolbarItems.Add (toolbarItem);
Label header = new Label {
Text = "Submitted Loans",
TextColor = Color.Gray,
FontAttributes = FontAttributes.Bold,
FontSize = 30,
HorizontalOptions = LayoutOptions.Center
};
// Create a data template from the type ImageCell
var cell = new DataTemplate (typeof(MenuCell));
ListView listView = new ListView {
ItemsSource = VetData.GetData (),
ItemTemplate = cell, // Set the ImageCell to the item template for the listview
//SeparatorColor = Color.Transparent
};
listView.RowHeight = 75;
listView.BackgroundColor = Color.Transparent;
// Push the list view down below the status bar on iOS.
if (Device.Idiom == TargetIdiom.Phone) {
Padding = new Thickness (10, Device.OnPlatform (20, 0, 0), 0, 0);
} else if (Device.Idiom == TargetIdiom.Tablet) {
Padding = new Thickness (150, Device.OnPlatform (50, 0, 0), 150, 10);
} else {
}
// Set the content for the page.
this.Content = new StackLayout {
Spacing = 20,
Children = {
header,
listView
}
};
listView.ItemSelected += async (sender, e) => {
if (e.SelectedItem != null) {
//do what you want with the selectedItem
// Navigation with back push
await Navigation.PushAsync (new LeadViewController ());
}
//then init the selectedItem of the listview to enable it to be selected again
listView.SelectedItem = null;
};
}
async void OnLogoutButtonClicked (object sender, EventArgs e)
{
// Navigation with out back push
Navigation.InsertPageBefore (new LoginViewController (), this);
await Navigation.PopAsync ();
}
}
}
LeadViewController.cs：MasterDetailScreen：屏幕面临错误
using System;
using System.Collections.Generic;
using Xamarin.Forms;
namespace eMO_Xamarin
{
public class LeadViewController : MasterDetailPage
{
public LeadViewController ()
{
this.BackgroundImage = "Bg6.jpg";
var menuPage = new MenuPage ();
menuPage.OnMenuSelect = (categoryPage) => {
Detail = new NavigationPage (categoryPage);
if (Device.Idiom == TargetIdiom.Phone) {
IsPresented = false;
} else if (Device.Idiom == TargetIdiom.Tablet) {
IsPresented = true;
} else {
IsPresented = true;
}
};
Master = menuPage;
Detail = new NavigationPage (new LetsGetStartedPage ());
MasterBehavior = MasterBehavior.Default;
}
}
}
答案 0 :(得分：1)
您的根页是导航页面。您还添加了一个带有导航页面的MasterDetial页面。
MasterDetail或Navigation应该是根，而不是彼此在一起。您不能在其他
中包含2个导航页面您可以将导航页面作为MasterDetail中的详细信息，或者您可以在导航页面中拥有MasterDetail，但您无法在导航页面内的任何级别拥有导航页面。这是仅限Android的限制，但最终会使其成为Xamarin Forms限制。
这是您的错误代码：
Detail = new NavigationPage (new LetsGetStartedPage ());
我认为您可以尝试以下代码：
Detail = new LetsGetStartedPage ();
或
namespace eMO_Xamarin
{
public class App : Application
{
public App ()
{
var nav = new LoginViewController ();
nav.BarBackgroundColor = Color.FromHex("#EEEEEE");
nav.BarTextColor = Color.FromHex("#424242");
MainPage = nav;
}
}
}
答案 1 :(得分：0)
试试这段代码：
listView.ItemSelected += async (sender, e) => {
if (e.SelectedItem != null) {
//do what you want with the selectedItem
// Navigation with back push
await Navigation.PushAsync (new NavigationPage(new LeadViewController ()));
}
//then init the selectedItem of the listview to enable it to be selected again
listView.SelectedItem = null;
};