我有一个带有集合视图的页面。我有一个按钮，允许用户从集合视图数据生成 pdf 并共享 pdf。生成过程需要几秒钟，因为有很多数据，所以我想我应该显示进度条或进度环之类的东西，以让用户等待并且在此过程中什么都不做。我尝试使用内容视图显示类似弹出窗口的内容。这是内容视图的代码：
<ContentView x:Name="popupLoadingView" BackgroundColor="Transparent" Padding="10, 0" IsVisible="false" HorizontalOptions="Center" VerticalOptions="Center">
<StackLayout VerticalOptions="Center" HorizontalOptions="Center">
<StackLayout Orientation="Vertical" HeightRequest="150" WidthRequest="200" BackgroundColor="White">
<ActivityIndicator x:Name="activityIndicator" Margin="0,50,0,0" VerticalOptions="Center" HorizontalOptions="Center" Color="Black" WidthRequest="30" HeightRequest="30" ></ActivityIndicator>
<Label x:Name="lblLoadingText" TextColor="Black" VerticalOptions="Center" HorizontalOptions="Center" VerticalTextAlignment="Center" Text="Loading..."></Label>
</StackLayout>
</StackLayout>
</ContentView>
这是我的收藏视图的代码
<?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="isc_alphaApp.Inventory">
<ContentPage.ToolbarItems >
<ToolbarItem Order="Secondary"
Text="logout"
Priority="2"
/>
</ContentPage.ToolbarItems>
<ContentPage.Resources>
<Style TargetType="Grid">
<Setter Property="VisualStateManager.VisualStateGroups">
<VisualStateGroupList>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="Selected">
<VisualState.Setters>
<Setter Property="BackgroundColor"
Value="#ffc40c" />
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateGroupList>
</Setter>
</Style>
</ContentPage.Resources>
<ContentPage.Content>
<StackLayout >
<SearchBar HorizontalOptions="FillAndExpand" x:Name="search" BackgroundColor="#ffc40c"/>
<CollectionView x:Name="lstl"
SelectionChanged="lstl_SelectionChanged"
SelectionMode="Single"
>
<CollectionView.Header>
<Grid Padding="2" ColumnSpacing="1" RowSpacing="1" >
<Grid.RowDefinitions>
<RowDefinition Height="35" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="0.7*" />
<ColumnDefinition Width="0.3*"/>
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="0.5*" />
</Grid.ColumnDefinitions>
<Label Grid.Column="0"
Text="Code"
FontAttributes="Bold"
LineBreakMode="TailTruncation"
HorizontalOptions="Center"
VerticalOptions="Center"
TextColor="Black"/>
<Label Grid.Column="1"
Text="Description"
FontAttributes="Bold"
LineBreakMode="TailTruncation"
HorizontalOptions="Center"
VerticalOptions="Center"
TextColor="Black"/>
<Label
TextColor="Black"
Grid.Column="2"
Text="Unit"
LineBreakMode="TailTruncation"
FontAttributes="Bold"
HorizontalOptions="Center"
VerticalOptions="Center"
/>
<Label
Grid.Column="3"
Text="Qty"
LineBreakMode="TailTruncation"
FontAttributes="Bold"
HorizontalOptions="Center"
TextColor="Black"
VerticalOptions="Center"
/>
<Label
TextColor="Black"
Grid.Column="4"
Text="U.Price"
LineBreakMode="TailTruncation"
FontAttributes="Bold"
HorizontalOptions="Center"
VerticalOptions="Center"
/>
</Grid>
</CollectionView.Header>
<CollectionView.ItemTemplate>
<DataTemplate>
<Grid Padding="1" ColumnSpacing="1" RowSpacing="0">
<Grid.RowDefinitions>
<RowDefinition Height="40" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="0.7*" />
<ColumnDefinition Width="0.3*" />
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="0.5*" />
</Grid.ColumnDefinitions>
<Label HorizontalOptions="Center"
Grid.Column="0"
TextColor="Black"
Text="{Binding itemcode}"
VerticalOptions="Center"
LineBreakMode="TailTruncation" />
<Label
Grid.Column="1"
VerticalOptions="Center"
HorizontalOptions="Center"
TextColor="Black"
Text="{Binding name}"
LineBreakMode="TailTruncation" />
<Label
Grid.Column="2"
TextColor="Black"
Text="{Binding itemsunitcode}"
LineBreakMode="TailTruncation"
VerticalOptions="Center"
HorizontalOptions="Center"
FontAttributes="Italic"
/>
<Label
TextColor="Black"
Grid.Column="3"
VerticalOptions="Center"
HorizontalOptions="Center"
Text="{Binding currentQuantity}"
LineBreakMode="TailTruncation"
FontAttributes="Italic"
/>
<Label
Grid.Column="4"
TextColor="Black"
Text="{Binding CostPrice}"
LineBreakMode="TailTruncation"
VerticalOptions="Center"
HorizontalOptions="Center"
FontAttributes="Italic"
/>
</Grid>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
<StackLayout VerticalOptions="EndAndExpand" HorizontalOptions="FillAndExpand" Orientation="Horizontal" BackgroundColor="#ffc40c">
<StackLayout Style="{StaticResource ButtonNavigationBarStackLayoutStyle}" x:Name="stckcol">
<Image Margin="0,10,0,10" x:Name="imgAdd" Style="{StaticResource ButtonNavigationBarImageStyle}" />
<Label Text="del" Style="{StaticResource ButtonNavigationBarLabelStyle}" x:Name="col_add_remove"></Label>
</StackLayout>
<StackLayout Style="{StaticResource ButtonNavigationBarStackLayoutStyle}" x:Name="stckfilter">
<Image Margin="0,10,0,10" x:Name="imgfilter" Style="{StaticResource ButtonNavigationBarImageStyle}" />
<Label Text="Filter" Style="{StaticResource ButtonNavigationBarLabelStyle}"></Label>
</StackLayout>
<StackLayout Style="{StaticResource ButtonNavigationBarStackLayoutStyle}" x:Name="stckshare">
<Image Margin="0,10,0,10" x:Name="imgshare" Style="{StaticResource ButtonNavigationBarImageStyle}" />
<Label Text="Share" Style="{StaticResource ButtonNavigationBarLabelStyle}"></Label>
</StackLayout>
</StackLayout>
</StackLayout>
</ContentPage.Content>
</ContentPage>
我尝试在集合视图代码的开头添加内容视图代码，但它没有出现在预期的位置。我希望它在集合视图布局顶部和屏幕中间看起来像一个警报。这是pdf生成的代码：
shareTap.Tapped += (sender, e) =>
{
popupLoadingView.IsVisible = true;
activityIndicator.IsRunning = true;
requestPermission();
};
async public void requestPermission()
{
var newstatus= Plugin.Permissions.Abstractions.PermissionStatus.Unknown;
var status = Plugin.Permissions.Abstractions.PermissionStatus.Unknown;
status = await CrossPermissions.Current.CheckPermissionStatusAsync<StoragePermission>();
if (status != Plugin.Permissions.Abstractions.PermissionStatus.Granted)
{
newstatus = await CrossPermissions.Current.RequestPermissionAsync<StoragePermission>();
if (newstatus == Plugin.Permissions.Abstractions.PermissionStatus.Granted)
{
generatePdf();
}
}
else
{
generatePdf();
}
}
private void generatePdf()
{
try
{
PdfDocument document = new PdfDocument();
//Add a new PDF page.
PdfPage page = document.Pages.Add();
//Get the font file as stream.
Stream fontStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("isc_alphaApp.Assets.arial.ttf");
//Create a new PdfTrueTypeFont instance.
PdfTrueTypeFont font = new PdfTrueTypeFont(fontStream, 14);
//Create a new bold stylePdfTrueTypeFont instance.
PdfTrueTypeFont boldFont = new PdfTrueTypeFont(fontStream, 14, PdfFontStyle.Bold);
page.Graphics.DrawString("Items", boldFont, PdfBrushes.Black, PointF.Empty);
//Create PdfGrid.
PdfGrid pdfGrid = new PdfGrid();
List<items_display> list_pdf = new List<items_display>();
for (int i = 0; i < list_total.Count; i++)
{
list_pdf.Add(new items_display { Code = list_total[i].itemcode, Description = list_total[i].name, Unit = list_total[i].itemsunitcode, Qty = list_total[i].currentQuantity, Price = list_total[i].CostPrice });
}
//Add values to list
List<items_display> data = list_pdf;
//Add list to IEnumerable.
IEnumerable<items_display> dataTable = data;
PdfStringFormat format_eng = new PdfStringFormat();
format_eng.TextDirection = PdfTextDirection.LeftToRight;
format_eng.Alignment = PdfTextAlignment.Center;
//Assign data source.
pdfGrid.DataSource = dataTable;
pdfGrid.Headers[0].Cells[0].StringFormat = format_eng;
pdfGrid.Headers[0].Cells[1].StringFormat = format_eng;
pdfGrid.Headers[0].Cells[2].StringFormat = format_eng;
pdfGrid.Headers[0].Cells[3].StringFormat = format_eng;
pdfGrid.Headers[0].Cells[4].StringFormat = format_eng;
//Assign bold font to pdfGrid header.
pdfGrid.Headers[0].Style.Font = boldFont;
//Assign font to PdfGrid.
pdfGrid.Style.Font = font;
Regex regex = new Regex("[\u0600-\u06ff]|[\u0750-\u077f]|[\ufb50-\ufc3f]|[\ufe70-\ufefc]");
//Create String format with RTL text direction and center text alignment.
PdfStringFormat format = new PdfStringFormat();
format.TextDirection = PdfTextDirection.RightToLeft;
format.Alignment = PdfTextAlignment.Center;
for (int i = 0; i < data.Count; i++)
{
if (regex.IsMatch(data[i].Code))
{
pdfGrid.Rows[i].Cells[0].StringFormat = format;
}
else
{
pdfGrid.Rows[i].Cells[0].StringFormat = format_eng;
}
if (regex.IsMatch(data[i].Description))
{
pdfGrid.Rows[i].Cells[1].StringFormat = format;
}
else
{
pdfGrid.Rows[i].Cells[1].StringFormat = format_eng;
}
if (regex.IsMatch(data[i].Unit))
{
pdfGrid.Rows[i].Cells[2].StringFormat = format;
}
else
{
pdfGrid.Rows[i].Cells[2].StringFormat = format_eng;
}
pdfGrid.Rows[i].Cells[3].StringFormat = format_eng;
pdfGrid.Rows[i].Cells[4].StringFormat = format_eng;
}
//Assign string format to draw RTL text with center alsignment
//pdfGrid.Rows[0].Cells[1].StringFormat = format;
//pdfGrid.Rows[1].Cells[1].StringFormat = format;
//Draw grid to the page of PDF document.
pdfGrid.Draw(page, new Syncfusion.Drawing.PointF(0, 20));
String file_Path;
string path = DependencyService.Get<getpath>().path();
file_Path = System.IO.Path.Combine(path.ToString(), "items.pdf");
FileStream stream = new FileStream(file_Path, FileMode.Create);
document.Save(stream);
//Close the document
document.Close(true);
Share.RequestAsync(new ShareFileRequest
{
Title = "Share PDF",
File = new ShareFile(file_Path)
});
}
catch(Exception exp)
{
DisplayAlert("No Space", "Not Enough Storage!", "Okay");
}
}
我尝试使内容视图可见的地方似乎也不正确，因为在生成 pdf 之前它不会显示。我希望它在用户单击按钮后出现。