Xamarin 中的表格部分 URL 调用 [英] Table Section URL Calling in Xamarin
本文介绍了Xamarin 中的表格部分 URL 调用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想显示两部分的tableviewcontroller.我有两个 url 可以调用以获取 json 对象并将它们列在 tableviewcontroller 中.我无法弄清楚如何创建一个可以处理两个不同 List 实例的 TableSource.
我在这里发布完整的源代码.如果有人能够帮助我解决这个问题，我会很高兴，或者分享一个有用的链接，或者分享代码.
<块引用> public override nint RowsInSection(UITableView tableview, nint section)返回未设置对象引用"错误.在我看来，一旦我从第一个 url 获取数据并尝试将 tableview 制表，但是，当时的其他 URL 数据可能还没有准备好.
命名空间 TPM{部分类 IViewController : UIViewController{公共列表任务；公共列表任务；public InboxViewController (IntPtr handle) : base (handle){this.Title = "里面";}公共覆盖无效 ViewDidLoad(){base.ViewDidLoad();收件箱();收件箱();}公共无效 CInbox(){var client = new RestClient("URL");client.Authenticator = new HttpBasicAuthenticator ("admin", "admin");var request = new RestRequest("其他部分网址");request.AddHeader("Accept", "application/json");request.AddHeader("Content-Type", "application/json");client.ExecuteAsync(请求，响应 => {cTasks = Newtonsoft.Json.JsonConvert.DeserializeObject>(响应.内容)；InvokeOnMainThread (() => {TableView.Source= new TableSource(cTasks,this,0);TableView.ReloadData();});});}公共无效 GInbox(){var client = new RestClient("URL");client.Authenticator = new HttpBasicAuthenticator ("admin", "admin");var request = new RestRequest("其余 URL");request.AddHeader("Accept", "application/json");request.AddHeader("Content-Type", "application/json");client.ExecuteAsync(请求，响应 => {aTasks = Newtonsoft.Json.JsonConvert.DeserializeObject>(响应.内容)；InvokeOnMainThread (() => {TableView.Source= new TableSource(aTasks,this,1);TableView.ReloadData();});});}公共类表源:UITableViewSource{ListcTableItems;ListaTableItems;国际定义;字符串 cellIdentifier="TableCell";私有 IViewController iv;public TableSource (Listitems, IViewController vc, int def){如果(定义== 0){cTableItems=items;}否则如果(定义== 1){aTableItems=items;}iv=vc；定义=定义；}公共覆盖 nint NumberOfSections (UITableView tableView){返回2；}公共覆盖 nfloat GetHeightForHeader (UITableView tableView, nint 部分){如果(部分== 0){返回 40；}如果(部分== 1){返回 40；}返回 40；}公共覆盖 UIView GetViewForHeader(UITableView tableView, nint section){UIView headerView = new UIView(new RectangleF (0, 0, (float)UIScreen.MainScreen.Bounds.Width, (float)tableView.SectionHeaderHeight));headerView.BackgroundColor = UIColor.Black;UILabel sectionTitle = new UILabel( new RectangleF(10, (float)((headerView.Frame.Height - 22)/2), 200, 24));sectionTitle.Font = UIFont.BoldSystemFontOfSize(22);sectionTitle.TextColor = UIColor.White;sectionTitle.TextAlignment = UITextAlignment.Right;如果(部分== 0){sectionTitle.Text = "Cmed";}否则如果(部分== 1){sectionTitle.Text = "Asy";}headerView.AddSubview(sectionTitle);返回标题视图；}公共覆盖 nint RowsInSection(UITableView tableview, nint section){如果(部分== 0)返回 cTableItems.Count;别的返回 aTableItems.Count;}公共覆盖 UITableViewCell GetCell (UITableView tableView, Foundation.NSIndexPath indexPath){UITableViewCell cell = tableView.DequeueReusableCell(cellIdentifier);如果(单元格 == 空)cell = new UITableViewCell(UITableViewCellStyle.Subtitle, cellIdentifier);如果(indexPath.Section == 0){cell.TextLabel.Text = cTableItems [indexPath.Row].displayName;cell.DetailTextLabel.Lines = 3;cell.DetailTextLabel.Text = "Process ID:" + cTableItems [indexPath.Row].processInstanceId + "\n" + DateTime.Parse (Convert.ToDateTime (cTableItems [indexPath.Row].createdOn).ToShortTimeString());if (cTableItems [indexPath.Row].priority == 0) {cell.ImageView.Image = UIImage.FromFile ("Images/green.png");}else if (cTableItems [indexPath.Row].priority == 1) {cell.ImageView.Image = UIImage.FromFile ("Images/yellow.png");}else if (cTableItems [indexPath.Row].priority == 2) {cell.ImageView.Image = UIImage.FromFile("Images/red.png");}}否则如果(indexPath.Section == 1){cell.TextLabel.Text = assignTableItems [indexPath.Row].displayName;cell.DetailTextLabel.Lines = 3;cell.DetailTextLabel.Text = "进程 ID:" + aTableItems [indexPath.Row].processInstanceId + "\n" + DateTime.Parse (Convert.ToDateTime (aTableItems [indexPath.Row].createdOn).ToShortTimeString());if (aTableItems [indexPath.Row].priority == 0) {cell.ImageView.Image = UIImage.FromFile ("Images/green.png");}else if (aTableItems [indexPath.Row].priority == 1) {cell.ImageView.Image = UIImage.FromFile ("Images/yellow.png");}else if (aTableItems [indexPath.Row].priority == 2) {cell.ImageView.Image = UIImage.FromFile("Images/red.png");}}cell.Accessory = UITableViewCellAccessory.DisclosureIndicator;返回单元格；}公共覆盖 nfloat GetHeightForRow (UITableView tableView, Foundation.NSIndexPath indexPath){返回 60；}}}} 基于 Jason 的回答:我收到以下错误:
基于 Jason 回答的第二次更新:
基于 Jason 回答的第三次更新:
解决方案
不是在构造函数中传递两组数据，而是将它们作为属性传递 - 这允许您在创建 Source 之后设置它们，这很有用因为您是异步获取数据的.
公共类TableSource:UITableViewSource{公共列表cTableItems;公共列表aTableItems;字符串 cellIdentifier="TableCell";私有 IViewController iv;公共表源(IViewController vc){aTableItems = new List();cTableItems = new List();iv=vc；} 然后在创建 VC 时创建一次源
public override void ViewDidLoad(){base.ViewDidLoad();TableView.Source = new TableSource(this);收件箱();收件箱();}最后，当你得到数据时不要重新创建你的源，只需用数据更新它:(对你的其他数据集重复同样的事情)
public void CInbox(){var client = new RestClient("URL");client.Authenticator = new HttpBasicAuthenticator ("admin", "admin");var request = new RestRequest("其他部分网址");request.AddHeader("Accept", "application/json");request.AddHeader("Content-Type", "application/json");//request.Method = (string)"GET";client.ExecuteAsync(请求，响应 => {cTasks = Newtonsoft.Json.JsonConvert.DeserializeObject>(响应.内容)；InvokeOnMainThread (() => {((TableSource)this.TableView.Source).cTableItems = cTasks;TableView.ReloadData();});}); I would like to display two section tableviewcontroller. I have two urls to call to get json object and tabulate them in tableviewcontroller. I could not able to figure out how to Create a single TableSource that can handle two different instances of List.
I am posting here full source code here. I will be glad if any one able to help me out in this problem, either share a link that would be useful, or share the code.
public override nint RowsInSection(UITableView tableview, nint section)returns me an "object reference not set" error. It seems to me that once I fecth data from the first url and it tries to tabulate tableview, however, the other URL data at that time may not be ready.
namespace TPM
{
partial class IViewController : UIViewController
{
public List<HumanTask> cTasks;
public List<HumanTask> aTasks;
public InboxViewController (IntPtr handle) : base (handle)
{
this.Title = "Inside";
}
public override void ViewDidLoad()
{
base.ViewDidLoad ();
GInbox ();
CInbox ();
}
public void CInbox()
{
var client = new RestClient ("URL");
client.Authenticator = new HttpBasicAuthenticator ("admin", "admin");
var request = new RestRequest ("other part URL");
request.AddHeader ("Accept", "application/json");
request.AddHeader ("Content-Type", "application/json");
client.ExecuteAsync (request, response => {
cTasks = Newtonsoft.Json.JsonConvert.DeserializeObject<List<HTask>> (response.Content);
InvokeOnMainThread (() => {
TableView.Source= new TableSource(cTasks,this,0);
TableView.ReloadData();
});
});
}
public void GInbox()
{
var client = new RestClient ("URL");
client.Authenticator = new HttpBasicAuthenticator ("admin", "admin");
var request = new RestRequest ("the rest URL");
request.AddHeader ("Accept", "application/json");
request.AddHeader ("Content-Type", "application/json");
client.ExecuteAsync (request, response => {
aTasks = Newtonsoft.Json.JsonConvert.DeserializeObject<List<HTask>> (response.Content);
InvokeOnMainThread (() => {
TableView.Source= new TableSource(aTasks,this,1);
TableView.ReloadData();
});
});
}
public class TableSource:UITableViewSource{
List<HTask>cTableItems;
List<HTask>aTableItems;
int defi;
string cellIdentifier="TableCell";
private IViewController iv;
public TableSource (List<HTask>items, IViewController vc, int def)
{
if(def==0)
{
cTableItems=items;
}
else if(def==1)
{
aTableItems=items;
}
iv=vc;
defi=def;
}
public override nint NumberOfSections (UITableView tableView)
{
return 2;
}
public override nfloat GetHeightForHeader (UITableView tableView, nint section)
{
if(section==0){
return 40;
}
if(section == 1) {
return 40;
}
return 40;
}
public override UIView GetViewForHeader(UITableView tableView, nint section)
{
UIView headerView = new UIView(new RectangleF (0, 0, (float)UIScreen.MainScreen.Bounds.Width, (float)tableView.SectionHeaderHeight));
headerView.BackgroundColor = UIColor.Black;
UILabel sectionTitle = new UILabel( new RectangleF(10, (float)((headerView.Frame.Height - 22) / 2), 200, 24));
sectionTitle.Font = UIFont.BoldSystemFontOfSize(22);
sectionTitle.TextColor = UIColor.White;
sectionTitle.TextAlignment = UITextAlignment.Right;
if (section == 0) {
sectionTitle.Text = "Cmed";
}
else if (section == 1) {
sectionTitle.Text = "Asy";
}
headerView.AddSubview(sectionTitle);
return headerView;
}
public override nint RowsInSection(UITableView tableview, nint section)
{
if (section == 0)
return cTableItems.Count;
else
return aTableItems.Count;
}
public override UITableViewCell GetCell (UITableView tableView, Foundation.NSIndexPath indexPath)
{
UITableViewCell cell = tableView.DequeueReusableCell(cellIdentifier);
if (cell == null)
cell = new UITableViewCell(UITableViewCellStyle.Subtitle, cellIdentifier);
if (indexPath.Section == 0) {
cell.TextLabel.Text = cTableItems [indexPath.Row].displayName;
cell.DetailTextLabel.Lines = 3;
cell.DetailTextLabel.Text = "Process ID:" + cTableItems [indexPath.Row].processInstanceId + "\n" + DateTime.Parse (Convert.ToDateTime (cTableItems [indexPath.Row].createdOn).ToShortTimeString ());
if (cTableItems [indexPath.Row].priority == 0) {
cell.ImageView.Image = UIImage.FromFile ("Images/green.png");
}
else if (cTableItems [indexPath.Row].priority == 1) {
cell.ImageView.Image = UIImage.FromFile ("Images/yellow.png");
}
else if (cTableItems [indexPath.Row].priority == 2) {
cell.ImageView.Image = UIImage.FromFile ("Images/red.png");
}
}
else if (indexPath.Section == 1) {
cell.TextLabel.Text = assignTableItems [indexPath.Row].displayName;
cell.DetailTextLabel.Lines = 3;
cell.DetailTextLabel.Text = "Process ID:" + aTableItems [indexPath.Row].processInstanceId + "\n" + DateTime.Parse (Convert.ToDateTime (aTableItems [indexPath.Row].createdOn).ToShortTimeString ());
if (aTableItems [indexPath.Row].priority == 0) {
cell.ImageView.Image = UIImage.FromFile ("Images/green.png");
}
else if (aTableItems [indexPath.Row].priority == 1) {
cell.ImageView.Image = UIImage.FromFile ("Images/yellow.png");
}
else if (aTableItems [indexPath.Row].priority == 2) {
cell.ImageView.Image = UIImage.FromFile ("Images/red.png");
}
}
cell.Accessory = UITableViewCellAccessory.DisclosureIndicator;
return cell;
}
public override nfloat GetHeightForRow (UITableView tableView, Foundation.NSIndexPath indexPath)
{
return 60;
}
}
}
}
Based on Jason answer: I am getting the following error:
Second update based on Jason answer:
Third update based on Jason answer:
解决方案
Instead of passing the two sets of data in the constructor, pass them as properties - this allows you to set them after the Source has been created, which is useful since you are getting the data asynchronously.
public class TableSource:UITableViewSource{
public List<HTask> cTableItems;
public List<HTask> aTableItems;
string cellIdentifier="TableCell";
private IViewController iv;
public TableSource (IViewController vc)
{
aTableItems = new List<HTask>();
cTableItems = new List<HTask>();
iv=vc;
}
Then create your Source once when you create the VC
public override void ViewDidLoad()
{
base.ViewDidLoad ();
TableView.Source = new TableSource(this);
GInbox ();
CInbox ();
}
Finally, when you get the data don't recreate your Source, just update it with the data: (repeat the same thing for your other dataset)
public void CInbox()
{
var client = new RestClient ("URL");
client.Authenticator = new HttpBasicAuthenticator ("admin", "admin");
var request = new RestRequest ("other part URL");
request.AddHeader ("Accept", "application/json");
request.AddHeader ("Content-Type", "application/json");
//request.Method = (string)"GET";
client.ExecuteAsync (request, response => {
cTasks = Newtonsoft.Json.JsonConvert.DeserializeObject<List<HTask>> (response.Content);
InvokeOnMainThread (() => {
((TableSource)this.TableView.Source).cTableItems = cTasks;
TableView.ReloadData();
});
});
这篇关于Xamarin 中的表格部分 URL 调用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
