簡易ハンズオン用スニペット

1_info.md

天気API

Current weather data - OpenWeatherMap

位置情報

Xamarin.Essentials:位置情報 - Xamarin | Microsoft Docs

MainPage.xaml

<StackLayout>
    <Frame Padding="24"
            BackgroundColor="#2196F3"
            CornerRadius="0">
        <Label HorizontalTextAlignment="Center"
                FontSize="36"
                Text="Welcome to Xamarin.Forms!"
                TextColor="White" />
    </Frame>
    <Label Padding="20,10"
            FontSize="Title"
            Text="お天気確認" />
    <Entry x:Name="LocationText"
            Margin="20,5"
            Text="品川区" />
    <Button Margin="20,5"
            Clicked="Button_Clicked"
            Text="天気取得" />
    <Label x:Name="WeatherLabel"
            Margin="20,5"
            Text="" />
</StackLayout>

MainPage.xaml.cs

public partial class MainPage : ContentPage
{
    private static readonly HttpClient _client = new HttpClient();

    public MainPage()
    {
        InitializeComponent();
    }

    private async void Button_Clicked(object sender, EventArgs e)
    {
        try
        {
            var request = new HttpRequestMessage
            {
                Method = HttpMethod.Post,
                RequestUri = new Uri($"https://api.openweathermap.org/data/2.5/weather?q={LocationText.Text},jp&units=metric&lang=ja&appid=faea356fd4ddaf18f9950b22a437c6c3")
            };

            var response = await _client.SendAsync(request);
            response.EnsureSuccessStatusCode();

            var json = await response.Content.ReadAsStringAsync();
            var weather = JsonConvert.DeserializeObject<WeatherInfo>(json);

            WeatherLabel.Text = $"{weather.Name} の天気は {weather.Weather.FirstOrDefault().Main} {weather.Weather.FirstOrDefault().Description}。\n" +
                $"現在の気温は {weather.Main.Temp}℃で、湿度は {weather.Main.Humidity}％です。";
        }
        catch (Exception ex)
        {
            WeatherLabel.Text = "見つかりませんでした。";
        }
            
    }
}

Weather.cs

public class WeatherInfo
{
    [JsonProperty("coord")]
    public Coord Coord { get; set; }

    [JsonProperty("weather")]
    public List<Weather> Weather { get; set; }

    [JsonProperty("base")]
    public string Base { get; set; }

    [JsonProperty("main")]
    public Main Main { get; set; }

    [JsonProperty("visibility")]
    public long Visibility { get; set; }

    [JsonProperty("wind")]
    public Wind Wind { get; set; }

    [JsonProperty("clouds")]
    public Clouds Clouds { get; set; }

    [JsonProperty("dt")]
    public long Dt { get; set; }

    [JsonProperty("sys")]
    public Sys Sys { get; set; }

    [JsonProperty("timezone")]
    public long Timezone { get; set; }

    [JsonProperty("id")]
    public long Id { get; set; }

    [JsonProperty("name")]
    public string Name { get; set; }

    [JsonProperty("cod")]
    public long Cod { get; set; }
}

public class Clouds
{
    [JsonProperty("all")]
    public long All { get; set; }
}

public class Coord
{
    [JsonProperty("lon")]
    public double Lon { get; set; }

    [JsonProperty("lat")]
    public double Lat { get; set; }
}

public class Main
{
    [JsonProperty("temp")]
    public double Temp { get; set; }

    [JsonProperty("feels_like")]
    public double FeelsLike { get; set; }

    [JsonProperty("temp_min")]
    public double TempMin { get; set; }

    [JsonProperty("temp_max")]
    public double TempMax { get; set; }

    [JsonProperty("pressure")]
    public long Pressure { get; set; }

    [JsonProperty("humidity")]
    public long Humidity { get; set; }
}

public class Sys
{
    [JsonProperty("type")]
    public long Type { get; set; }

    [JsonProperty("id")]
    public long Id { get; set; }

    [JsonProperty("country")]
    public string Country { get; set; }

    [JsonProperty("sunrise")]
    public long Sunrise { get; set; }

    [JsonProperty("sunset")]
    public long Sunset { get; set; }
}

public class Weather
{
    [JsonProperty("id")]
    public long Id { get; set; }

    [JsonProperty("main")]
    public string Main { get; set; }

    [JsonProperty("description")]
    public string Description { get; set; }

    [JsonProperty("icon")]
    public string Icon { get; set; }
}

public class Wind
{
    [JsonProperty("speed")]
    public double Speed { get; set; }

    [JsonProperty("deg")]
    public long Deg { get; set; }
}

z_gps-part.cs

try
{
    var location = await Geolocation.GetLastKnownLocationAsync();

    if (location != null)
    {
        var request = new HttpRequestMessage
        {
            Method = HttpMethod.Post,
            RequestUri = new Uri($"https://api.openweathermap.org/data/2.5/weather?lat={location.Latitude}&lon={location.Longitude}&units=metric&lang=ja&appid=faea356fd4ddaf18f9950b22a437c6c3")
        };

        var response = await _client.SendAsync(request);
        response.EnsureSuccessStatusCode();

        var json = await response.Content.ReadAsStringAsync();
        var weather = JsonConvert.DeserializeObject<WeatherInfo>(json);

        WeatherLabel.Text = $"{weather.Name} の天気は {weather.Weather.FirstOrDefault().Main} {weather.Weather.FirstOrDefault().Description}。\n" +
        $"現在の気温は {weather.Main.Temp}℃で、湿度は {weather.Main.Humidity}％です。";
    }
}
catch (FeatureNotSupportedException fnsEx)
{
    // Handle not supported on device exception
    WeatherLabel.Text = fnsEx.Message;
}
catch (FeatureNotEnabledException fneEx)
{
    // Handle not enabled on device exception
    WeatherLabel.Text = fneEx.Message;
}
catch (PermissionException pEx)
{
    // Handle permission exception
    WeatherLabel.Text = pEx.Message;
}
catch (Exception ex)
{
    // Unable to get location
    WeatherLabel.Text = ex.Message;
}