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Xamarin.Forms Text Analysis

Hello, In my previous article, I try to  wrote about the face recognition and in this article, i will try to make Text Analytics app. Text Analytics can be used for the different purposes. In the application, I will try to make sentiment analytics, language analytics, important entities or people analytics and key phrases of the text.

Firstly, Login into Azure and create a Text Analytics Api, it is easy to do. After the creation of the Api, create Xamarin.Forms blank application. In the app, i create a page which name is TextAnalyticsPage and then i made the design of this page.

 <ScrollView>
        <StackLayout Margin="10">
            <Editor Placeholder="Write Something :)"
                    HeightRequest="250"
                    TextColor="Black"
                    PlaceholderColor="Gray"
                    x:Name="myEditor"/>
            <Button Text="Analyze"
                    TextColor="White"
                    BackgroundColor="Green"
                    Clicked="ButtonAnalyze_Clicked"/>
            <ActivityIndicator Color="Green"
                               VerticalOptions="Center"
                               HorizontalOptions="Center"
                               IsVisible="False"
                               x:Name="myActivitIndicator"/>
            <Label x:Name="labelSentiment"
               Style="{StaticResource myLabelStyle}"/>
            <Label x:Name="labelLanguage"
               Style="{StaticResource myLabelStyle}"/>
            <ListView ItemsSource="{Binding .}"
                      HasUnevenRows="True"
                      IsVisible="False"
                      x:Name="listEntityDetails">
                <ListView.Header>
                    <Label Text="Entities ; "
                           Style="{StaticResource myLabelStyle}"
                           TextColor="Red"/>
                </ListView.Header>
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <Grid>
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="Auto"/>
                                    <RowDefinition Height="Auto"/>
                                    <RowDefinition Height="Auto"/>
                                </Grid.RowDefinitions>
                                <StackLayout Grid.Row="0"
                                             Orientation="Horizontal">
                                    <Label Style="{StaticResource myLabelStyle}">
                                        <Label.FormattedText>
                                            <FormattedString>
                                                <Span Text="Name : "/>
                                                <Span Text="{Binding Name}"/>
                                            </FormattedString>
                                        </Label.FormattedText>
                                    </Label>
                                    <Label Style="{StaticResource myLabelStyle}">
                                        <Label.FormattedText>
                                            <FormattedString>
                                                <Span Text="Type : "/>
                                                <Span Text="{Binding Type}"/>
                                            </FormattedString>
                                        </Label.FormattedText>
                                    </Label>
                                   
                                </StackLayout>
                                <StackLayout Grid.Row="1"
                                             Orientation="Horizontal">
                                    <Label Style="{StaticResource myLabelStyle}">
                                        <Label.FormattedText>
                                            <FormattedString>
                                                <Span Text="Sub-Type : "/>
                                                <Span Text="{Binding SubType}"/>
                                            </FormattedString>
                                        </Label.FormattedText>
                                    </Label>
                                    <Label Style="{StaticResource myLabelStyle}">
                                        <Label.FormattedText>
                                            <FormattedString>
                                                <Span Text="OffSet : "/>
                                                <Span Text="{Binding OffSet}"/>
                                            </FormattedString>
                                        </Label.FormattedText>
                                    </Label>
                                </StackLayout>
                                <StackLayout Grid.Row="2"
                                         Orientation="Horizontal">
                                    <Label Style="{StaticResource myLabelStyle}">
                                        <Label.FormattedText>
                                            <FormattedString>
                                                <Span Text="Length : "/>
                                                <Span Text="{Binding Length}"/>
                                            </FormattedString>
                                        </Label.FormattedText>
                                    </Label>
                                    <Label Style="{StaticResource myLabelStyle}">
                                        <Label.FormattedText>
                                            <FormattedString>
                                                <Span Text="Score : "/>
                                                <Span Text="{Binding Score}"/>
                                            </FormattedString>
                                        </Label.FormattedText>
                                    </Label>
                                </StackLayout>
                            </Grid>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
            <ListView ItemsSource="{Binding .}"
                      HasUnevenRows="False"
                      IsVisible="False"
                      x:Name="listKeyPhrases">
                <ListView.Header>
                    <StackLayout>
                        <Label Text="Key Phrases ; "
                               Style="{StaticResource myLabelStyle}"
                               TextColor="Red"/>
                    </StackLayout>
                </ListView.Header>
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <Label Text="{Binding KeyPhrase}"
                                   Style="{StaticResource myLabelStyle}"/>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </StackLayout>
    </ScrollView>

If you copy and paste the code, you will have the same design with me. After the design, we should make the analytics part. For the make analysis, I follow the Microsoft Documentation, you can reach by clicking here. We should add the Microsoft.Azure.CognitiveServices.Language.TextAnalytics nuget package to the our project. Now everything is good to code analysis but before that we should add the Subscription Key and End-Point.

private static readonly string subscriptionKey = "Key";
private static readonly string endpoint = "End-Point";

We should wrote the codes that which store the information and help us to connect with api;

 //Storing credentials
        class ApiKeyServiceClientCredentials : ServiceClientCredentials
        {
            private readonly string apiKey;

            public ApiKeyServiceClientCredentials(string apiKey)
            {
                this.apiKey = apiKey;
            }

            public override Task ProcessHttpRequestAsync(HttpRequestMessage request, CancellationToken cancellationToken)
            {
                if (request == null)
                {
                    throw new ArgumentNullException("request");
                }
                request.Headers.Add("Ocp-Apim-Subscription-Key", this.apiKey);
                return base.ProcessHttpRequestAsync(request, cancellationToken);
            }
        }

Codes for the Sentimental Analysis of the Text;

 // Sentiment Analyzing of Text
        public void SentimentAnalysisExample(TextAnalyticsClient client)
        {
            //Determining the language
            var detectedLanguage = client.DetectLanguage(myEditor.Text);
            string languageCode = detectedLanguage.DetectedLanguages[0].Iso6391Name;

            var result = client.Sentiment(myEditor.Text, languageCode);
            labelSentiment.Text = "Sentiment Score : " + result.Score;
        }

Codes for the Detect Language of the Text;

// Language Analyze of Text
        public void LanguageDetectionExample(TextAnalyticsClient client)
        {
            var result = client.DetectLanguage(myEditor.Text);
            labelLanguage.Text = "Language : " + result.DetectedLanguages[0].Name;
        }

Codes for the detect Entities and People in the Text;

// Entity Analyze of Text
        public void EntityRecognitionExample(TextAnalyticsClient client)
        {
            // Otomatically Language setted to the English
            var result = client.Entities(myEditor.Text);

            List<Entity> entities = new List<Entity>();

            if(result.Entities.Count != 0)
            {
                listEntityDetails.IsVisible = true;
                foreach (var entity in result.Entities)
                {
                    foreach (var match in entity.Matches)
                    {
                        entities.Add(new Entity
                        {
                            Name = entity.Name,
                            Length = match.Length.ToString(),
                            OffSet = match.Offset.ToString(),
                            Score = match.EntityTypeScore.ToString(),
                            SubType = entity.SubType,
                            Type = entity.Type
                        });
                    }
                }

                listEntityDetails.BindingContext = entities;
            }
            else
            {
                listEntityDetails.IsVisible = false;
            }
        }

Codes for the detect Key Phrases of the Text;

 // Analyzing of the Key Phrase in the Text
        public void KeyPhraseExtractionExample(TextAnalyticsClient client)
        {
            var result = client.KeyPhrases(myEditor.Text);

            List<Phrase> phrases = new List<Phrase>();

            if(result.KeyPhrases.Count != 0)
            {
                listKeyPhrases.IsVisible = true;
                foreach (string keyphrase in result.KeyPhrases)
                {
                    phrases.Add(new Phrase { KeyPhrase = keyphrase });
                }

                listKeyPhrases.BindingContext = phrases;
            }
            else
            {
                listKeyPhrases.IsVisible = false;
            }
            
        }

And the button event for the call all the functions;

private void ButtonAnalyze_Clicked(object sender, EventArgs e)
        {
            var credentials = new ApiKeyServiceClientCredentials(subscriptionKey);
            TextAnalyticsClient client = new TextAnalyticsClient(credentials)
            {
                Endpoint = endpoint
            };

            myActivitIndicator.IsVisible = true;
            myActivitIndicator.IsRunning = true;

            SentimentAnalysisExample(client);
            LanguageDetectionExample(client);
            EntityRecognitionExample(client);
            KeyPhraseExtractionExample(client);

            myActivitIndicator.IsVisible = false;
            myActivitIndicator.IsRunning = false;
        }

After the wroting all the codes above, Text Analysis will work perfectly. For your question, you can reach me via e-mail or comments.

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