Creating buttons in a for loop

Question

Hi all,

I'm new to Xamarin, so sorry if the question is a repeat or explained badly.

What I'm aiming to do is to create and display a number of buttons for each keyphrase found in a phrase and then have the selected keyword spoken back out of the device once the button is clicked. I'm having issues with trying to create buttons and display them within a for loop.
At current in my MainPage XAML I have two frames which display the sentence and one which I would hope will hold the buttons.

What I hoped would have created the buttons and displaye them (in main page code behind):

if (recognizer == null)
            {
                var config = SpeechConfig.FromSubscription(Constants.CognitiveServicesApiKey, Constants.CognitiveServicesRegion);
                var audioConfig = Microsoft.CognitiveServices.Speech.Audio.AudioConfig.FromDefaultMicrophoneInput();
                recognizer = new SpeechRecognizer(config);
                var recognizerkeyword = new KeywordRecognizer(audioConfig);
                recognizer.Recognized += (obj, args) =>
                { 

                    var response = client.ExtractKeyPhrases(args.Result.Text);
                    // pulls out the keywords from the sentence



                    foreach (string keyphrase in response.Value)
                    {

                        newButtonCreation(keyphrase);

                    }



                };

---

 void newButtonCreation(string keyphrase)

        {

            Device.BeginInvokeOnMainThread(() =>
            {
                if (!string.IsNullOrWhiteSpace(keyphrase))
                {
                    Xamarin.Forms.Button b = new Xamarin.Forms.Button() { HorizontalOptions = LayoutOptions.Fill, VerticalOptions = LayoutOptions.Fill, Text = keyphrase};
                    b.Clicked += async (sender, args) => await TextToSpeech.SpeakAsync(keyphrase);

                }
            }

            );

        }

This doesn't really do anything at the minute and I wonder if I need to edit my mainpage XAML form to display these newly created buttons, but I am unsure of how to do that.

TIA

Answer 1

I noticed two things in your code sample:

1- You are using a Frame for your buttons, but a Frame layout can only have one child. Use
StackLayout or any other Layout that can hold more than one child.

2- You are creating some buttons but never add them to your layout.

Here is a code sample:

void newButtonCreation(string keyphrase)

         {

             Device.BeginInvokeOnMainThread(() =>
             {
                 if (!string.IsNullOrWhiteSpace(keyphrase))
                 {
                     Xamarin.Forms.Button b = new Xamarin.Forms.Button
                       { 
                           HorizontalOptions = LayoutOptions.Fill, VerticalOptions = 
                           LayoutOptions.Fill, Text = keyphrase
                       };

                     b.Clicked += async (sender, args) => await TextToSpeech.SpeakAsync(keyphrase);

                    MyLayout.Children.Add(b);                        
                 }
             }

             );
         }

Where (MyLayout) is a StackLayout defined in XAML with (x:Name="MyLayout")

Let me know if that works for you. Best luck.

Answer 2

@Ahmad Thank you so much, this has massively helped me!!