c# - How to change the Action View for an ActionBar's menu item with Xamarin -

i have menu item icon in actionbar change progressbar when user click on it, run task, , change icon. below code have, nothing happens when menu item clicked.

the activity: importreferenceview.cs

public class importreferenceview : mvxactivity {     protected override void oncreate(bundle bundle)     {         base.oncreate(bundle);         setcontentview(resource.layout.importreferenceview);         actionbar.setdisplayshowcustomenabled(true);     }      public override bool oncreateoptionsmenu(android.views.imenu menu)     {         menuinflater.inflate(resource.menu.import_actions, menu);         return true;     }      public override bool onoptionsitemselected(android.views.imenuitem item)     {         switch (item.itemid)         {             case resource.id.action_import:                 item.setactionview(resource.layout.progressbar);                 item.expandactionview();                 var vm = ((importreferenceviewmodel)viewmodel);                 task task = task.run(() =>    vm.importcommand.execute(vm.selectedtablereferences));                 task.waitall(new task[] { task });                 item.collapseactionview();                 item.setactionview(null);                 break;             default:                 break;         }         return true;     } } 

the menu actions: import_actions.xml

<?xml version="1.0" encoding="utf-8" ?> <menu xmlns:android="http://schemas.android.com/apk/res/android" >    <item       android:id="@+id/action_import"       android:showasaction="always"       android:icon="@drawable/action_down"       android:title="refresh"/> </menu> 

the progressbar view: progressbar.axml

<?xml version="1.0" encoding="utf-8"?> <progressbar xmlns:android="http://schemas.android.com/apk/res/android"     android:id="@+id/progressbar2"     android:layout_width="wrap_content"     android:layout_height="wrap_content" /> 

i trying achieve xamarin 1 described in action bar/action view section of article

any or suggestion appreciated

here's how it:

public override bool oncreateoptionsmenu(imenu menu) {     menuinflater.inflate(resource.menu.home_menu, menu);      _refreshwrapper = new refreshactionbuttonwrapper(menu);     var set = this.createbindingset<homeview, homeviewmodel>();     set.bind(_refreshwrapper).for("isbusy").to(vm => vm.myservice.isbusy);     set.apply();      return true; } 

i use mvvmcross data binding bind isbusy property wrapper class. don't have that. can set isbusy property directly (see example below).

public class refreshactionbuttonwrapper {     private readonly imenu _optionsmenu;      public refreshactionbuttonwrapper(imenu optionsmenu)     {         _optionsmenu = optionsmenu;     }      private bool _isbusy;     public bool isbusy     {         { return _isbusy; }         set         {             _isbusy = value;              var dispatcher = mvxmainthreaddispatcher.instance;             dispatcher.requestmainthreadaction(() => setrefreshactionbuttonstate(_isbusy));         }     }      public void setrefreshactionbuttonstate(bool refreshing)     {         if (_optionsmenu == null) return;         var refreshitem = _optionsmenu.finditem(resource.id.refresh_action);         if (refreshing)         {             refreshitem.setactionview(resource.layout.actionbar_indeterminate_progress);         }         else         {             refreshitem.setactionview(null);         }     } } 

the trick change action view on main thread. mvvmcross provides method invoke request on main thread:

var dispatcher = mvxmainthreaddispatcher.instance; dispatcher.requestmainthreadaction(() => setrefreshactionbuttonstate(_isbusy)); 

then can this. use await wait import function complete. wrap isbusy status in try/finally, make sure isbusy set false, on exceptions.

public override bool onoptionsitemselected(android.views.imenuitem item) {     switch (item.itemid)     {         case resource.id.action_import:             try             {                 _refreshwrapper.isbusy = true;                 var vm = ((importreferenceviewmodel)viewmodel);                 await task.run(() => vm.importcommand.execute(vm.selectedtablereferences));                          }                          {                 _refreshwrapper.isbusy = false;             }             break;         default:             break;     }     return true; } 

btw: if derive view mvxactivity<importreferenceviewmodel> have typed viewmodel property , won't have cast it.