Triggering Activity Indicator in Xamarin Forms

Question

I have an icon on my Xamarin.Forms app, which when it is clicked, I would like to change it to an activity indicator. It looks as though I should use a Trigger, Event Trigge

Answer 1

There are a few ways of doing this.

You could simply give each of them an x:Name and then turn on/off IsRunning and IsVisible if you want to hide it.

I assume though that you have some data binding going on. Since IsRunning is a bool you could simply bind it to a boolean in your code behind. For instance In my ViewModel I have an IsBusy property and implement INotifyPropertyChanged:

public class MyViewModel : INotifyPropertyChanged
{


    public MyViewModel()
    {
    }

    private bool busy = false;

    public bool IsBusy
    {
        get { return busy; }
        set
        {
            if (busy == value)
                return;

            busy = value;
            OnPropertyChanged("IsBusy");
        }
    }


    public async Task GetMonkeysAsync()
    {
        if (IsBusy)
            return;


        try
        {
            IsBusy = true;

            //do stuff here that is going to take a while

        }
        finally
        {
            IsBusy = false;
        }
    }

    #region INotifyPropertyChanged implementation

    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string name)
    {
        var changed = PropertyChanged;
        if (changed == null)
            return;

        changed(this, new PropertyChangedEventArgs(name));

    }

    #endregion
}

Then in the XAML you can bind to IsBusy:

I think that should handle it. If you need a timer you could use the same binding that I have here and use Xamarin.Forms built in timer class.