Xamarin forms. Cant display json object in a list - json

Question

I am totally new in xamarin forms. I am trying to make an app that uses the TMDB api to display a list with movies but i am getting this exception:
Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[CinemaApp.Models.NowPlaying]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
This is my xaml file
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="CinemaApp.PlayingNowPage">
<ContentPage.Content>
<AbsoluteLayout HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
<StackLayout x:Name="SLMovies" AbsoluteLayout.LayoutFlags="All"
AbsoluteLayout.LayoutBounds="0,0,1,1">
<ListView x:Name="MoviesListView"
HasUnevenRows="True"
SeparatorVisibility="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Frame>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.4*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Image Source="{Binding full_poster_path}" Grid.Column="0"
HeightRequest="120"
WidthRequest="150"/>
<StackLayout Grid.Column="1">
<Label Text="{Binding title}"
TextColor="#E91E63"
FontAttributes="Bold"/>
<Label Text="{Binding vote_average}"/>
<Label Text="{Binding release_date}">
</Label>
<StackLayout
Orientation="Horizontal"
HorizontalOptions="FillAndExpand">
<Label HorizontalOptions="EndAndExpand"
Text="{Binding Duration}">
</Label>
</StackLayout>
</StackLayout>
</Grid>
</Frame>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
<StackLayout
x:Name="SLLoader"
IsVisible="True"
Padding="12"
AbsoluteLayout.LayoutFlags="PositionProportional"
AbsoluteLayout.LayoutBounds="0.5,0.5,-1,-1">
<ActivityIndicator
IsRunning="True"
Color="#00000000"/>
<Label
Text="Loading..."
HorizontalOptions="Center"
TextColor="Red"/>
</StackLayout>
</AbsoluteLayout>
</ContentPage.Content>
</ContentPage>
This is the class for the objects
using System;
using System.Collections.Generic;
using System.Text;
namespace CinemaApp.Models
{
public class NowPlaying
{
public int id { get; set; }
public bool video { get; set; }
public double vote_average { get; set; }
public string title { get; set; }
public string poster_path { get; set; }
public string original_title { get; set; }
public string release_date { get; set; }
public string full_poster_path
{
get
{
if (string.IsNullOrEmpty(poster_path))
{
return string.Empty;
}
return string.Format("https://image.tmdb.org/t/p/w185/" +
poster_path);
}
}
}
}
And this the main class:
namespace CinemaApp
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class PlayingNowPage : ContentPage
{
public PlayingNowPage ()
{
InitializeComponent ();
GetMovies();
}
private async void GetMovies()
{
try
{
SLLoader.IsVisible = true;
HttpClient client = new HttpClient();
var response = await client.GetStringAsync(
"https://api.themoviedb.org/3/movie/now_playing?
api_key=XXXX&language=en-US&page=1");
var movies = JsonConvert.DeserializeObject<List<NowPlaying>>
(response);
Console.WriteLine("rere "+movies);
MoviesListView.ItemsSource = movies;
}
catch (Exception e)
{
Console.WriteLine("Error: " + e);
}
finally
{
SLLoader.IsVisible = false;
}
}
}
}

Answer 1

Your NowPlaying model only has the data for the object in one now playing result. If you look at the response, like in an example on the website: https://developers.themoviedb.org/3/movies/get-now-playing
{
"page": 1,
"results": [
{
"poster_path": "/e1mjopzAS2KNsvpbpahQ1a6SkSn.jpg",
"adult": false,
"overview": "From DC Comics comes the Suicide Squad, an antihero team of incarcerated supervillains who act as deniable assets for the United States government, undertaking high-risk black ops missions in exchange for commuted prison sentences.",
"release_date": "2016-08-03",
"genre_ids": [
14,
28,
80
],
"id": 297761,
"original_title": "Suicide Squad",
"original_language": "en",
"title": "Suicide Squad",
"backdrop_path": "/ndlQ2Cuc3cjTL7lTynw6I4boP4S.jpg",
"popularity": 48.261451,
"vote_count": 1466,
"video": false,
"vote_average": 5.91
},
{
"poster_path": "/lFSSLTlFozwpaGlO31OoUeirBgQ.jpg",
"adult": false,
"overview": "The most dangerous former operative of the CIA is drawn out of hiding to uncover hidden truths about his past.",
"release_date": "2016-07-27",
"genre_ids": [
28,
53
],
"id": 324668,
"original_title": "Jason Bourne",
"original_language": "en",
"title": "Jason Bourne",
"backdrop_path": "/AoT2YrJUJlg5vKE3iMOLvHlTd3m.jpg",
"popularity": 30.690177,
"vote_count": 649,
"video": false,
"vote_average": 5.25
},
{
"poster_path": "/tgfRDJs5PFW20Aoh1orEzuxW8cN.jpg",
"adult": false,
"overview": "Arthur Bishop thought he had put his murderous past behind him when his most formidable foe kidnaps the love of his life. Now he is forced to travel the globe to complete three impossible assassinations, and do what he does best, make them look like accidents.",
"release_date": "2016-08-25",
"genre_ids": [
80,
28,
53
],
"id": 278924,
"original_title": "Mechanic: Resurrection",
"original_language": "en",
"title": "Mechanic: Resurrection",
"backdrop_path": "/3oRHlbxMLBXHfMqUsx1emwqiuQ3.jpg",
"popularity": 20.375179,
"vote_count": 119,
"video": false,
"vote_average": 4.59
},
{
"poster_path": "/3ioyAtm0wXDyPy330Y7mJAJEHpU.jpg",
"adult": false,
"overview": "A high school senior finds herself immersed in an online game of truth or dare, where her every move starts to be manipulated by an anonymous community of \"watchers.\"",
"release_date": "2016-07-27",
"genre_ids": [
18,
53
],
"id": 328387,
"original_title": "Nerve",
"original_language": "en",
"title": "Nerve",
"backdrop_path": "/a0wohltYr7Tzkgg2X6QKBe3txj1.jpg",
"popularity": 7.17729,
"vote_count": 86,
"video": false,
"vote_average": 6.84
},
{
"poster_path": "/3S7V2Jd2G61LltoCsYUj4GwON5p.jpg",
"adult": false,
"overview": "A woman with a seemingly perfect life - a great marriage, overachieving kids, beautiful home, stunning looks and still holding down a career. However she's over-worked, over committed and exhausted to the point that she's about to snap. Fed up, she joins forces with two other over-stressed moms and all go on a quest to liberate themselves from conventional responsibilities, going on a wild un-mom like binge of freedom, fun and self-indulgence - putting them on a collision course with PTA Queen Bee Gwendolyn and her clique of devoted perfect moms.",
"release_date": "2016-07-28",
"genre_ids": [
35
],
"id": 376659,
"original_title": "Bad Moms",
"original_language": "en",
"title": "Bad Moms",
"backdrop_path": "/l9aqTBdafSo0n7u0Azuqo01YVIC.jpg",
"popularity": 6.450367,
"vote_count": 107,
"video": false,
"vote_average": 5.49
},
{
"poster_path": "/sRxazAAodkAWVPJighRAsls2zCo.jpg",
"adult": false,
"overview": "A falsely accused nobleman survives years of slavery to take vengeance on his best friend who betrayed him.",
"release_date": "2016-08-17",
"genre_ids": [
12,
36,
18
],
"id": 271969,
"original_title": "Ben-Hur",
"original_language": "en",
"title": "Ben-Hur",
"backdrop_path": "/A4xbEpe9LevQCdvaNC0z6r8AfYk.jpg",
"popularity": 6.379067,
"vote_count": 60,
"video": false,
"vote_average": 3.83
},
{
"poster_path": "/aRRLpsusORQxOpFkZvXdk00TkoY.jpg",
"adult": false,
"overview": "Nate Foster, a young, idealistic FBI agent, goes undercover to take down a radical white supremacy terrorist group. The bright up-and-coming analyst must confront the challenge of sticking to a new identity while maintaining his real principles as he navigates the dangerous underworld of white supremacy. Inspired by real events.",
"release_date": "2016-08-19",
"genre_ids": [
80,
18,
53
],
"id": 374617,
"original_title": "Imperium",
"original_language": "en",
"title": "Imperium",
"backdrop_path": "/9dMvJJ0eTVetq3kLwUXcphsY5H.jpg",
"popularity": 5.855316,
"vote_count": 33,
"video": false,
"vote_average": 6.05
},
{
"poster_path": "/4pUIQO6OqbzxrFLGMDf2dlplSR9.jpg",
"adult": false,
"overview": "Southside With You chronicles a single day in the summer of 1989 when the future president of the United States, Barack Obama, wooed his future First Lady on an epic first date across Chicago's South Side.",
"release_date": "2016-08-26",
"genre_ids": [
10749,
18
],
"id": 310888,
"original_title": "Southside With You",
"original_language": "en",
"title": "Southside With You",
"backdrop_path": "/fukREcpoPugi0yx6cVrFvsR7JBE.jpg",
"popularity": 5.229414,
"vote_count": 13,
"video": false,
"vote_average": 3.12
},
{
"poster_path": "/wJXku1YhMKeuzYNEHux7XtaYPsE.jpg",
"adult": false,
"overview": "Based on a true story, “War Dogs” follows two friends in their early 20s living in Miami during the first Iraq War who exploit a little-known government initiative that allows small businesses to bid on U.S. Military contracts. Starting small, they begin raking in big money and are living the high life. But the pair gets in over their heads when they land a 300 million dollar deal to arm the Afghan Military—a deal that puts them in business with some very shady people, not the least of which turns out to be the U.S. Government.",
"release_date": "2016-08-18",
"genre_ids": [
10752,
35,
18
],
"id": 308266,
"original_title": "War Dogs",
"original_language": "en",
"title": "War Dogs",
"backdrop_path": "/2cLndRZy8e3das3vVaK3BdJfRIi.jpg",
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},
{
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"adult": false,
"overview": "Pete is a mysterious 10-year-old with no family and no home who claims to live in the woods with a giant, green dragon named Elliott. With the help of Natalie, an 11-year-old girl whose father Jack owns the local lumber mill, forest ranger Grace sets out to determine where Pete came from, where he belongs, and the truth about this dragon.",
"release_date": "2016-08-10",
"genre_ids": [
12,
10751,
14
],
"id": 294272,
"original_title": "Pete's Dragon",
"original_language": "en",
"title": "Pete's Dragon",
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{
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"adult": false,
"overview": "59 year-old Ove is the block’s grumpy man. Several years ago he was deposed as president of the condominium association, but he could not give a damn about being deposed and therefore keeps looking over the neighborhood with an iron fist. When pregnant Parvaneh and her family move into the terraced house opposite Ove and accidentally back into Ove’s mailbox it sets off the beginning of an unexpected change in his life.",
"release_date": "2016-08-26",
"genre_ids": [
35,
18
],
"id": 348678,
"original_title": "En man som heter Ove",
"original_language": "sv",
"title": "A Man Called Ove",
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"adult": false,
"overview": "In the epic fantasy, scruffy, kindhearted Kubo ekes out a humble living while devotedly caring for his mother in their sleepy shoreside village. It is a quiet existence – until a spirit from the past catches up with him to enforce an age-old vendetta. Suddenly on the run from gods and monsters, Kubo’s chance for survival rests on finding the magical suit of armor once worn by his fallen father, the greatest samurai the world has ever known. Summoning courage, Kubo embarks on a thrilling odyssey as he faces his family’s history, navigates the elements, and bravely fights for the earth and the stars.",
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16,
14,
10751
],
"id": 313297,
"original_title": "Kubo and the Two Strings",
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18
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"dates": {
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},
"total_pages": 33,
"total_results": 649
}
You see that it is wrapped in a results object. So, you would need something like this:
public class RootObject
{
public NowPlaying[] Results { get; set; }
}
And deserialize into the RootObject. A great tool to get the structure of a JSON object is quicktype.io. Or, it is even baked into Visual Studio (Windows only). Copy your JSON object and go to Edit > Paste special > Paste JSON as Classes