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result from string array to textview when button clicked

https://s8.postimg.cc/nryfeo8xh/Screenshot_8.png
i have some code that has to add a string result from an array to a textView when a button is clicked.
it has 3 components
textView
editText
button
there's an array with results that when the button is clicked has to be added on the textView with the editText on top of the array random result
1st try
editText = hi there
click button
textview=
hi there
three (from array random result)
2nd try
editText = hi again
click button
textview=
hi again
two
hi there (previous result)
three (previous result)
text view is almost a log file
using Android.App;
using Android.Widget;
using Android.OS;
using System;
namespace APP
{
[Activity(Label = "APP", MainLauncher = true)]
public class MainActivity : Activity
{
string[] constStringArray = new string[] { "one", "two", "three" };
TextView res;
EditText edt;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
edt = FindViewById<EditText>(Resource.Id.editText1);
res = FindViewById<TextView>(Resource.Id.textView1);
Button btn = FindViewById<Button>(Resource.Id.button1);
btn.Click += Btn_Click;
}
private void Btn_Click(object sender, System.EventArgs e)
{
string constStringArray = res.Text.ToString();
res.Text = constStringArray;
}
}
}

Xamarin Forms: Android: Toast Notifications Clicked

I am on the most current version of Xamarin Forms. I have a Content Page. The Content Page has a content that has a Button. That Button has Button_Clicked event Which you can see below. I use IToastNitificator (https://github.com/EgorBo/Toasts.Forms.Plugin), and I try to pass when I send this notification after I close my app, and after I clicked the Notification my App doesn't pop up Again. Anybody can help me how can I reach this?
This is my Button_Clicked method:
private async void Button_Clicked(object sender, EventArgs e)
{
var notificator = DependencyService.Get<IToastNotificator>();
var options = new NotificationOptions()
{
Title = "Teszt",
Description = "Önnek teszteket kell kitöltenie!",
IsClickable = true
};
var result = await notificator.Notify(options);
if(result.Action == NotificationAction.Clicked)
{
await Navigation.PushAsync(new QuestionPage());
}
}
I registered this Dependency and It's working fine.
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
protected override void OnCreate (Bundle bundle)
{
TabLayoutResource = Resource.Layout.Tabbar;
ToolbarResource = Resource.Layout.Toolbar;
base.OnCreate (bundle);
Xamarin.Forms.DependencyService.Register<ToastNotification>();
Xamarin.Forms.DependencyService.Register<OpenAppAndroid>();
ToastNotification.Init(this);
BluetoothLowEnergyAdapter.Init(this);
global::Xamarin.Forms.Forms.Init (this, bundle);
LoadApplication (new Spirocco.App (BluetoothLowEnergyAdapter.ObtainDefaultAdapter(ApplicationContext)));
}
}

To reopen the Android application you need to set the ForceOpenAppOnNotificationTap to true in the AndroidOptions
Example:
var options = new NotificationOptions()
{
Title = "Teszt",
Description = "Önnek teszteket kell kitöltenie!",
IsClickable = true,
AndroidOptions = new AndroidOptions()
{
ForceOpenAppOnNotificationTap = true
}
};

How can I see css changes without restarting xamarin app

I'm building a xamarin app where I'm using a Preprocessed Razor Template as a webview. I used this guide to set it up: https://developer.xamarin.com/guides/cross-platform/advanced/razor_html_templates/
It's working great and all but every time I do some css changes I have to restart the app to see the css changes. Is there another way to do this so I don't have to restart the app every time?
I tried adding a button which reloads the webView but that did not work. This is my activity:
public class ItemWebViewActivity : Activity
{
WebView webView;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
var itemId = Intent.GetIntExtra("itemId", 0);
SetContentView(Resource.Layout.ItemWebView);
webView = FindViewById<WebView>(Resource.Id.webView);
var dataService = new AzureDataService();
var item = dataService.GetItem(itemId);
Button refreshButton = (Button)FindViewById(Resource.Id.refreshButton);
refreshButton.Click += ReloadPage;
var decodedDesc = WebUtility.HtmlDecode(item.Description);
var vm = new Item()
{
Artist = item.Artist,
Title = item.Title,
Picture = item.Picture,
Description = decodedDesc
};
var template = new ItemWebView() { Model = vm };
var page = template.GenerateString();
webView.LoadDataWithBaseURL("file:///android_asset/",page, "text/html", "charset=UTF-8",null);
}
private void ReloadPage(object sender, EventArgs e)
{
webView.Reload();
}
}
Would appreciate any help :)

2nd button will not work with event handler in Xamarin c# android app

MainActivity.cs
namespace testApp
{
[Activity (Label = "DHS HotKeys", MainLauncher = true, Icon = "#drawable/icon")]
public class MainActivity : Activity
{
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle);
// Set our view from the "main" layout resource
SetContentView (Resource.Layout.Main);
// Get our button from the layout resource,
// and attach an event to it
Button button1 = FindViewById<Button> (Resource.Id.button1);
Button button = FindViewById<Button> (Resource.Id.myButton);
button.Click += delegate {
var uri = Android.Net.Uri.Parse ("https://www.fridayparentportal.com/delran/");
var intent = new Intent (Intent.ActionView, uri);
StartActivity (intent);
};
button1.Click += (object sender, EventArgs e) => {
var uri2 = Android.Net.Uri.Parse ("http://dhs.delranschools.org/students/lunch_menu/");
var intent2 = new Intent (Intent.ActionView, uri2);
StartActivity (intent2);
};
}
}
}
Inside the resource designer:
public partial class Id
{
// aapt resource value: 0x7f050001
public const int button1 = 2131034113;
// aapt resource value: 0x7f050000
public const int myButton = 2131034112;
The 2nd button is set exactly like the first, but it does nothing when clicked, while the first one opens the webpage. The ID for 2nd button is #+id/button1
Thank you

write each button closer to their eventhandler, like this :
Button btn1 = FindViewById<Button>(Resource.Id.button1);
btn.Click += (object se,EventArgs e)
{
}

SharedPreferences value does not stick

I am trying to save a string to SharedPerferences like this:
Write
var prefs = Application.Context.GetSharedPreferences ("Janssen", FileCreationMode.WorldReadable);
var prefEditor = prefs.Edit ();
prefEditor.PutString ("SecurityToken", SecurityCode.Text);
prefEditor.Commit ();
Read
var prefs = Application.Context.GetSharedPreferences ("Janssen", FileCreationMode.WorldReadable);
var SecurityToken = prefs.GetString ("SecurityToken", null);
I am new to Android coming from iOS. I am trying to emulate NSUserDefaults in iOS. I am reading the SharedPreferences in a new activity, maybe that is what causes the problem? I am not sure. I also have no idea what to set as default value.

Are you re-deploying between writing your SharedPreferences and reading them? This often wipes the SharedPreferences.
I have just tested them and they work fine between two Activities:
WritePrefsAcitivity.cs
using Android.App;
using Android.Content;
using Android.Widget;
using Android.OS;
namespace Derrrp
{
[Activity (Label = "Derrrp", MainLauncher = true)]
public class WritePrefsActivity : Activity
{
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle);
SetContentView (Resource.Layout.Write);
var prefs = Application.Context.GetSharedPreferences("MySharedPrefs", FileCreationMode.Private);
var prefsEditor = prefs.Edit();
var ed = FindViewById<EditText>(Resource.Id.editText1);
ed.AfterTextChanged += (sender, e) => {
prefsEditor.PutString("MyPref", e.Editable.ToString());
prefsEditor.Commit();
};
Button button = FindViewById<Button> (Resource.Id.myButton);
button.Click += delegate {
var intent = new Intent(this, typeof(ReadPrefsActivity));
StartActivity(intent);
};
}
}
}
ReadPrefsActivity.cs
using Android.App;
using Android.Content;
using Android.OS;
using Android.Widget;
namespace Derrrp
{
[Activity (Label = "ReadPrefsActivity")]
public class ReadPrefsActivity : Activity
{
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle);
SetContentView(Resource.Layout.Read);
var tv = FindViewById<TextView>(Resource.Id.myTextView);
var button = FindViewById<Button>(Resource.Id.myButton);
var prefs = Application.Context.GetSharedPreferences("MySharedPrefs", FileCreationMode.Private);
button.Click += (sender, e) => {
tv.Text = prefs.GetString("MyPref", "");
};
}
}
}
The defValue can be set to anything you want. This is the value that will be chosen if the preference you are trying to get is empty.
NOTE: If you are using it to store some secret information it is advised to use FileCreationMode.Private and even use something that makes it only readable by the application, such as encryption.

I am not sure what is the error you have, but below is an example i used before for saving a string using shared preferences.
I used to set default value to "", so that while reading, if the value was not saved before, it will set the variable to empty string. You can read the shared preferences in any new activity , shared preferences is per application not activity ..
example:
writing string:
String pass = "abcdefg";
SharedPreferences preferences = getSharedPreferences("pref", 0);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("savedPass", pass);
editor.commit();
reading string:
SharedPreferences preferences = getSharedPreferences("pref", 0);
String mypassword = preferences.getString("savedPass", "");