我是 Xamarin 的新手，一般都在开发原生应用程序（我过去制作过 html5 应用程序）。 我已经开始了一个 Xamarin.Forms 项目，我正在尝试联系一个类似 API 的 REST（需要获取一个返回 json 数组的 URL）。
通常来自 C# 我会使用 RestSharp 并使用 RestClient 执行此调用。 虽然我没有从 Xamarin Studio 安装该软件包，但我已经安装了 Microsoft HTTP 库。
我很确定这是一项非常微不足道的任务，我只是无法调整我在网上找到的示例来为我工作。
请谁可以发布这是如何完成的（请记住我是新手，所以不要指望我理解与普通控制台应用程序不同的所有内容）？
【问题讨论】：
标签： rest xamarin xamarin.forms
使用 HTTP 客户端和 JSON.NET 很容易，这里是一个 GET 示例：
public async Task<List<Appointment>> GetDayAppointments(DateTime day)
{
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + App.apiToken);
//Your url.
string resourceUri = ApiBaseAddress;
HttpResponseMessage result = await client.GetAsync (resourceUri, CancellationToken.None);
if (result.IsSuccessStatusCode) {
try {
return GetDayAppointmentsList(result);
} catch (Exception ex) {
Console.WriteLine (ex.Message);
}
} else {
if(TokenExpired(result)){
App.SessionExpired = true;
App.ShowLogin();
}
return null;
}
return null;
}
private List<Appointment> GetDayAppointmentsList(HttpResponseMessage result){
string content = result.Content.ReadAsStringAsync ().Result;
JObject jresponse = JObject.Parse (content);
var jarray = jresponse ["citas"];
List<Appointment> AppoinmentsList = new List<Appointment> ();
foreach (var jObj in jarray) {
Appointment newApt = new Appointment ();
newApt.Guid = (int)jObj ["id"];
newApt.PatientId = (string)jObj ["paciente"];
newApt.Name = (string)jObj ["nombre"];
newApt.FatherLstName = (string)jObj ["paterno"];
newApt.MotherLstName = (string)jObj ["materno"];
string strStart = (string)jObj ["horaIni"];
TimeSpan start;
TimeSpan.TryParse (strStart, out start);
newApt.StartDate = start;
string strEnd = (string)jObj ["horaFin"];
TimeSpan end;
TimeSpan.TryParse (strEnd, out end);
newApt.EndDate = end;
AppoinmentsList.Add (newApt);
}
return AppoinmentsList;
}
【讨论】：
我使用 System.Net.WebClient 和我们的 asp.net WebAPI 接口：
public string GetData(Uri uri)
{//uri like "https://webapi.main.cz/api/root"
string ret = "ERROR";
try
{
using (WebClient webClient = new WebClient())
{
//You can set webClient.Headers there
webClient.Encoding = System.Text.Encoding.UTF8;
ret = webClient.DownloadString(uri));//Test some data received
//In ret you can have JSON string
}
}
catch (Exception ex) { ret = ex.Message; }
return ret;
}
4
public string SendData(Uri uri, byte[] data)
{//uri like https://webapi.main.cz/api/PostCheckLicence/
string ret = "ERROR";
try
{
using (WebClient webClient = new WebClient())
{
webClient.Headers[HttpRequestHeader.Accept] = "application/octet-stream";
webClient.Headers[HttpRequestHeader.ContentType] = "text/bytes";
webClient.Encoding = System.Text.Encoding.ASCII;
byte[] result = webClient.UploadData(uri, data);
ret = Encoding.ASCII.GetString(result);
if (ret.Contains("\"ResultWebApi\":\"OK"))
{//In ret you can have JSON string
}
else
{
}
}
}
catch (Exception ex) { ret = ex.Message; }
return ret;
}
x
【讨论】：
我的 Github repo 中有一些示例。只需抓住那里的课程并尝试一下。该 API 非常易于使用：
await new Request<T>()
.SetHttpMethod(HttpMethod.[Post|Put|Get|Delete].Method) //Obligatory
.SetEndpoint("http://www.yourserver.com/profilepic/") //Obligatory
.SetJsonPayload(someJsonObject) //Optional if you're using Get or Delete, Obligatory if you're using Put or Post
.OnSuccess((serverResponse) => {
//Optional action triggered when you have a succesful 200 response from the server
//serverResponse is of type T
})
.OnNoInternetConnection(() =>
{
// Optional action triggered when you try to make a request without internet connetion
})
.OnRequestStarted(() =>
{
// Optional action triggered always as soon as we start making the request i.e. very useful when
// We want to start an UI related action such as showing a ProgressBar or a Spinner.
})
.OnRequestCompleted(() =>
{
// Optional action triggered always when a request finishes, no matter if it finished successufully or
// It failed. It's useful for when you need to finish some UI related action such as hiding a ProgressBar or
// a Spinner.
})
.OnError((exception) =>
{
// Optional action triggered always when something went wrong it can be caused by a server-side error, for
// example a internal server error or for something in the callbacks, for example a NullPointerException.
})
.OnHttpError((httpErrorStatus) =>
{
// Optional action triggered when something when sending a request, for example, the server returned a internal
// server error, a bad request error, an unauthorize error, etc. The httpErrorStatus variable is the error code.
})
.OnBadRequest(() =>
{
// Optional action triggered when the server returned a bad request error.
})
.OnUnauthorize(() =>
{
// Optional action triggered when the server returned an unauthorize error.
})
.OnInternalServerError(() =>
{
// Optional action triggered when the server returned an internal server error.
})
//AND THERE'S A LOT MORE OF CALLBACKS THAT YOU CAN HOOK OF, CHECK THE REQUEST CLASS TO MORE INFO.
.Start();
还有几个例子。
【讨论】：
对于我所有的 Xamarin Forms 应用程序，我使用 Tiny.RestClient。 很容易得到，也很容易使用。
你必须下载这个nuget。
之后就很容易使用了：
var client = new TinyRestClient(new HttpClient(), "http://MyAPI.com/api");
var cities = client.
GetRequest("City").
AddQueryParameter("id", 2).
AddQueryParameter("country", "France").
ExecuteAsync<City>> ();
希望有所帮助。
【讨论】：