Question

app delegate：

public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
    {
        // Get current device token
        var DeviceToken = deviceToken.Description;
        if (!string.IsNullOrWhiteSpace(DeviceToken))
        {
            DeviceToken = DeviceToken.Trim('<').Trim('>');
        }

        // Get previous device token
        var oldDeviceToken = NSUserDefaults.StandardUserDefaults.StringForKey("token");

        // Has the token changed?
        if (string.IsNullOrEmpty(oldDeviceToken) || !oldDeviceToken.Equals(DeviceToken))
        {
            //TODO: Put your own logic here to notify your server that the device token has changed/been created!
        }

        // Save new device token
        //NSUserDefaults.StandardUserDefaults.SetString(DeviceToken, "token");
        IOSUserPreferences userPreference = new IOSUserPreferences();
        userPreference.SetString("token", DeviceToken);
    }

我的PCL界面：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace neoFly_Montana
{
public interface IUserPreferences
{
    void SetString(string key, string value);
    string GetString(string key);
}
}

当我在pcl中调用接口时：

string token = App.UserPreferences.GetString("token");

App.xaml.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Xamarin.Forms;
using Xamarin.Forms.Maps;

namespace neoFly_Montana
{
public partial class App : Application
{
    public App()
    {
        InitializeComponent();

        MainPage = new NavigationPage(new Views.Splash2()) { BarTextColor = Color.FromHex("#f98e1e") };
    }

    protected override void OnStart()
    {
        // Handle when your app starts
    }

    protected override void OnSleep()
    {
        // Handle when your app sleeps
    }

    protected override void OnResume()
    {
        // Handle when your app resumes
    }

    public static IUserPreferences UserPreferences { get; private set; }

    public static void Init(IUserPreferences userPreferencesImpl)
    {
        App.UserPreferences = userPreferencesImpl;
    }
}
}

关于iphone项目：

using Foundation;
using System;
using System.Collections.Generic;
using System.Text;

namespace neoFly_Montana.iOS
{
class IOSUserPreferences : IUserPreferences
{
    public void SetString(string key, string value)
    {
        NSUserDefaults.StandardUserDefaults.SetString(value, key);
    }

    public string GetString(string key)
    {
        return NSUserDefaults.StandardUserDefaults.StringForKey(key);
    }
}
}

在Android上它运行正常，保存并获取数据......

作为测试，我试图保存数据并将其放在app delegate上并且工作正常，我可以看到它访问IOSUserPreferences脚本，当我尝试在pcl上获取它时会出现问题

当我尝试获取保存的数据时，仅在ios中，它为null并且应用程序崩溃...我注意到它没有访问iphone项目上的获取字符串方法。。有人知道发生了什么吗？

我无法将ios数据保存在其内存中（xamarin.forms - interface）

0 个答案: