Xamarin.android 更新自定义listviewAdapter
我想将新数据添加到我的listviewAdapter中,我尝试清除它之前的所有数据,并通知现在有数据,但它似乎不起作用。我遵循了规则,但不起作用 有人知道为什么吗Xamarin.android 更新自定义listviewAdapter,xamarin.android,listview-adapter,Xamarin.android,Listview Adapter,我想将新数据添加到我的listviewAdapter中,我尝试清除它之前的所有数据,并通知现在有数据,但它似乎不起作用。我遵循了规则,但不起作用 有人知道为什么吗 public class ReportsListViewAdapter : BaseAdapter<IMobileReport>, IFilterable { internal List<IMobileReport> originalData; internal List<IMobileR
public class ReportsListViewAdapter : BaseAdapter<IMobileReport>, IFilterable
{
internal List<IMobileReport> originalData;
internal List<IMobileReport> reports;
private Context context;
public override IMobileReport this[int position] => reports[position];
public ReportsListViewAdapter(Context context, IEnumerable<IMobileReport> reports)
{
this.reports = reports.OrderBy(report => report.StudyDate).ToList();
this.context = context;
Filter = new ReportsFilter(this);
}
public override int Count => this.reports.Count;
public Filter Filter { get; private set; }
public override long GetItemId(int position)
{
return position;
}
public void updateReportsList(List<MobileReport> newlist)
{
reports.AddRange(newlist);
this.NotifyDataSetChanged();
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
View row = convertView;
if(row == null)
{
row = LayoutInflater.From(context).Inflate(Resource.Layout.listView_reports_row, null, false);
}
var txtName = row.FindViewById<TextView>(Resource.Id.txtName);
txtName.Text = reports[position].Student.Name;
var txtFirstName = row.FindViewById<TextView>(Resource.Id.txtFirstName);
txtFirstName.Text = reports[position].Student.FirstName;
var txtSource = row.FindViewById<TextView>(Resource.Id.txtSource);
txtSource.Text = reports[position].Source;
var txtCritical = row.FindViewById<TextView>(Resource.Id.txtCritical);
txtSource.Text = reports[position].Critical.ToString();
return row;
}
}
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
reports = new List<IMobileReport>();
//Init();
_reportsHubConnector = new ReportsHubConnector();
#pragma warning disable 4014 // We cannot await this task here because the signature of the inherited method is void
Task.Factory.StartNew(async () =>
{
await _reportsHubConnector.StartConnection();
await _reportsHubConnector.SendT();
}, TaskCreationOptions.PreferFairness);
#pragma warning restore 4014
Console.WriteLine("HomeActivity: OnCreate");
SetContentView(Resource.Layout.activity_reports);
SupportActionBar.SetDisplayShowTitleEnabled(false);
SupportActionBar.SetDisplayHomeAsUpEnabled(false);
SupportActionBar.SetDisplayShowHomeEnabled(true);
WireUpElements();
listView = FindViewById<ListView>(Resource.Id.reports);
ReportsListViewAdapter adapter = new ReportsListViewAdapter(this, reports);
listView.Adapter = adapter;
searchView = FindViewById<SearchView>(Resource.Id.searchView1);
searchView.QueryTextChange += this.Filter;
listView.ItemClick += ItemClicked;
criticalButton = FindViewById<LinearLayout>(Resource.Id.AuthenticatorButton);
criticalButton.Click += criticalClicked;
_reportsHubConnector.ReportsRecieved += (reports) =>
{
adapter.updateReportsList(reports);
};
}
我尝试过清除它之前的所有数据,并通知现在有数据,但它似乎不起作用
在共享代码中,不看clear方法,您可以添加reports.clear()
,以检查它是否有效
public void updateReportsList(List<MobileReport> newlist)
{
reports.Clear();
reports.AddRange(newlist);
this.NotifyDataSetChanged();
}
将reports
参数更改为tmpreparts
,以避免与原始数据reports
混合
因此,还有另一种更新适配器数据的常用方法,如下所示:
_reportsHubConnector.ReportsRecieved += (tmpReports) =>
{
adapter.updateReportsList(tmpReports);
};
_reportsHubConnector.ReportsRecieved += (reports) =>
{
List<IMobileReport> tmp = new List<IMobileReport>();
tmp = reports ; // use a tmp list data for updating , not using original list data
adapter.updateReportsList(tmp);
};
其效果是:
可能的原因:
public class HomeScreenAdapter : BaseAdapter<TableItem> {
List<TableItem> items;
Activity context;
public HomeScreenAdapter(Activity context, List<TableItem> items)
: base()
{
this.context = context;
this.items = new List<TableItem>();
this.items.AddRange(items);
//this.items = items;
}
public override long GetItemId(int position)
{
return position;
}
public override TableItem this[int position]
{
get { return items[position]; }
}
public override int Count
{
get { return items.Count; }
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var item = items[position];
View view = convertView;
if (view == null) // no view to re-use, create new
view = context.LayoutInflater.Inflate(Resource.Layout.CustomView, null);
view.FindViewById<TextView>(Resource.Id.Text1).Text = item.Heading;
view.FindViewById<TextView>(Resource.Id.Text2).Text = item.SubHeading+" items";
view.FindViewById<ImageView>(Resource.Id.Image).SetImageResource(item.ImageResourceId);
return view;
}
public void UpdateListView(List<TableItem> newTableItem)
{
items.Clear();
items.AddRange(newTableItem);
NotifyDataSetChanged();
}
}
如果此处使用等号,则项目的指针地址将更改。更新数据时,它无法指向原始数据源,因此更新无法成功
因此,在这里您的代码的构造函数
可以进行如下修改,以检查它是否工作:
public ReportsListViewAdapter(Context context, IEnumerable<IMobileReport> reports)
{
//this.reports = reports.OrderBy(report => report.StudyDate).ToList();
this.reports = new List<IMobileReport>();
this.reports.AddRange(reports.OrderBy(report => report.StudyDate).ToList());
this.context = context;
Filter = new ReportsFilter(this);
}
public ReportsListViewAdapter(上下文,IEnumerable报告)
{
//this.reports=reports.OrderBy(report=>report.StudyDate.ToList();
this.reports=新列表();
this.reports.AddRange(reports.OrderBy(report=>report.StudyDate.ToList());
this.context=上下文;
过滤器=新报告过滤器(此);
}
相关:这是。好的,更新时会出现什么现象?是发生错误信息还是其他日志信息?在调用NotifyDataSetChanged后没有发生错误,我确实看到他触发了适配器的计数和位置,但是视图没有更新。视图没有被调用,所以它没有更新视图guess@Max你能分享一下在哪里调用更新方法的代码吗?我知道你需要调用RunOnUiThread,但是当我这样做的时候。RunOnUiThread没有被调用
public HomeScreenAdapter(Activity context, List<TableItem> items)
: base()
{
this.context = context;
this.items = new List<TableItem>();
//this.items.AddRange(items);
this.items = items;
}
public ReportsListViewAdapter(Context context, IEnumerable<IMobileReport> reports)
{
//this.reports = reports.OrderBy(report => report.StudyDate).ToList();
this.reports = new List<IMobileReport>();
this.reports.AddRange(reports.OrderBy(report => report.StudyDate).ToList());
this.context = context;
Filter = new ReportsFilter(this);
}