I've created some pages
this.content1 = new DetailPage("ContentPage1");
this.content2 = new DetailPage("ContentPage2");
and I have defined a field
private View detailView;
with the following layout
Content = new StackLayout
{
Padding = new Thickness(0, Device.OnPlatform<int>(20, 0, 0), 0, 0),
Orientation = StackOrientation.Horizontal,
Children = {
buttonContainer,
this.detailView,
},
};
On a button click the detailView should be exchanged
private void Button1_Clicked(object sender, EventArgs e)
{
this.detailView = this.content1.Content;
}
The click event is called, but the view isn't updated. Is this the wrong way to exchange a "subview" in a container? How is this done?
You need to remove the current detailView from the Children collection and then add your new view afterward. Simply swapping the value of detailView will not affect the visual UI.
If I am understanding the context of your code snippets correctly, then this should resolve the problem in your Button1_Clicked handler:
((StackLayout) Content).Children.Remove(this.detailView);
this.detailView = this.content1.Content;
((StackLayout) Content).Children.Add(this.detailView);
Related
Our Xamarin.Forms app works online and offline by downloading an original database to the cell phone and then syncing the SQLite database with the online database.
Our users need a way to see if they are online and if the changes they made got uploaded to the online database. What I try to achieve is to show the sync status at the top of every ContentPage, so the users can see this information all the time while working with the app.
What I tried is this: create a class "SyncInfoContentPage" that inherits from ContentPage. All ContentPages I already wrote will now not inherit from ContentPage anymore but from SyncInfoContentPage.
The SyncInfoContentPage automatically takes its Content and replaces it with a new Stacklayout that includes the SyncInfo and the original content. By doing this I don't have to rewrite the 77 ContentPages we already have.
This code works fine on Android, but on iOS the SyncInfo is not visible and (even worse) my ContentPages that inherit from SyncInfoContentPage do not react to anything anymore.
Here is my code:
public class SyncInfoContentPage : ContentPage
{
private readonly Frame SyncInfo;
public SyncInfoContentPage()
{
SyncInfo = BuildSyncInfo(); //Creates the frame with the sync Information
PropertyChanged += SyncInfoContentPage_PropertyChanged;
}
private void SyncInfoContentPage_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
// Add the SyncInfo Frame on top of the Content when the Content gets changed
if (e.PropertyName.Equals("Content"))
{
bool change = false;
// If the content already is a StackLayout, check if the SyncInfo already got added, so that theres no infinite loop.
if (Content is StackLayout)
{
var check = Content as StackLayout;
if (!check.Children.Contains(SyncInfo))
{
change = true;
}
}
else // if the Content is no StackLayout, the SyncInfo Frame can't be inside the Content yet
{
change = true;
}
if (change)
{
var layout = Content; // This is a reference, probably the error?
Device.BeginInvokeOnMainThread(() =>
{
Content = new StackLayout
{
Children = { SyncInfo, layout }
};
});
}
}
}
}
The problem is probably that iOS doesn't like this part:
var layout = Content;
Content = new StackLayout { Children = { SyncInfo, layout } };
Thanks in advance for your help and any suggestions :-)
I got it to work. The solution is simple but strange. You have to add the original Content after you added the SyncInfo status bar.
var layoutOld = Content;
var layoutNew = new StackLayout
{
Children = { SyncInfo }
};
Content = layoutNew;
layoutNeu.Children.Add(layoutOld);
Am trying to load ItemSource of a picker when the picker is focused.
But the data is not loaded on 1st focus.
here is the code sample
List<object> itmSrc;
Picker picker = new Picker();
itmSrc = Controls[i].ItemSource;
picker.Focused += BindItemSourceOnFocus;
public void BindItemSourceOnFocus(object sender, FocusEventArgs e)
{
var p = e.VisualElement as Picker;
p.ItemsSource = itmSrc;
}
If any other different approach is possible, let me know.
You can do it adding items on an async method, or another thread. Load the data on view focus is just transferring the issue to another place, and it gives a bad user experience at all.
If you run a code block inside a Task.Run(), for example, this code will be executed on another thread, and the interface should not hang on data loading.
Something like this:
public class MyPage : ContentPage
{
List<object> itmSrc;
Picker picker;
public MyPage()
{
// Your stuff goes here
itmSrc = new List<object>();
picker = new Picker();
StackLayout content = new StackLayout();
content.Crindren.Add(picker);
this.Content = content;
Task.Run(() => LoadData());
}
private void LoadData()
{
// Get your data from anywhere and put it on the itemSrc from here.
// Then...
picker.ItemsSource = itmSrc;
}
}
I hope it helps.
First thing, I have an Editor.I can Identify if the user entered any text in that Edior.But i need to return something when the user tapped on the Editor. How to achieve this?
var msgEditor = new Editor
{
Margin = new Thickness(10, 0, 10, 0),
HeightRequest = App.ScreenHeight,
};
Secong thing, Editor is inside the scrollview.When i tapped on the Editor scrollview scrolls down.I need to manually pull down to see the cursor.How to set content offset when i tapped on Editor?
ScrollView scroll = new ScrollView
{
Content = msgEditor,
};
Content = scroll;
On the editor, you have the focus event that notifies you that the user tapped the editor. You can do as follow :
{
var editor = new Editor();
editor.Focused += EditorOnFocused;
}
private void EditorOnFocused(object sender, FocusEventArgs focusEventArgs)
{
//do your stuff
}
Currently with ListView's I've only found that you can create a template for cells, which makes each cell look exactly the same. You can't have multiple custom cells in the listview. There are work-arounds like hiding the content in the cell depending on the content, but this seems pretty hacky.
The reason I want to use a listview over a tableview is because we plan on doing inserts, deletions, dynamically showing certain cells, and listview's can be binded to a data source.
Create your own ViewCell which overrides binding context change method. When the binding changes set the ViewCell's view to one that matches the type of view model and also set the height of the cell. Below is a quick sample that should give you an idea how to accomplish it.
public class DataTemplateCell1 : ViewCell
{
protected override void OnBindingContextChanged()
{
var vm1 = this.BindingContext as ViewModel1;
if (vm1 != null)
{
this.View = new View1() { HeightRequest = 40 };
this.Height = this.View.HeightRequest;
return;
}
var vm2 = this.BindingContext as ViewModel2;
if (vm2 != null)
{
this.View = new View2() { HeightRequest = 80 };
this.Height = this.View.HeightRequest;
return;
}
base.OnBindingContextChanged();
}
}
I've created a master detail page on the left side using Xamarin.Forms, how about creating the same for the right side?
Below is my sample code for the left slider menu;
public class App
{
static MasterDetailPage MDPage;
public static Page GetMainPage()
{
return MDPage = new MasterDetailPage {
Master = new ContentPage {
Title = "Master",
BackgroundColor = Color.Silver,
Icon = Device.OS == TargetPlatform.iOS ? "menu.png" : null,
Content = new StackLayout {
Padding = new Thickness(5, 50),
Children = { Link("A"), Link("B"), Link("C") }
},
},
Detail = new NavigationPage(new ContentPage {
Title = "A",
Content = new Label { Text = "A" }
}),
};
}
static Button Link(string name)
{
var button = new Button {
Text = name,
BackgroundColor = Color.FromRgb(0.9, 0.9, 0.9)
};
button.Clicked += delegate {
MDPage.Detail = new NavigationPage(new ContentPage {
Title = name,
Content = new Label { Text = name }
});
MDPage.IsPresented = false;
};
return button;
}
}
This does not exists in the Xamarin.Forms controls set, but you can create your own, with renderers for each platform.
You'll find the required information on http://developer.xamarin.com/guides/cross-platform/xamarin-forms/custom-renderer/
Solution here
this is now supported in xamarin forms 3.0 and up, NO custom renderers
needed !! or third party libraries.
the trick is to force the layout to RTL,
while flow direction works, its hard to make the top nav bar to follow,
below is the solution for that problem, it works... let me know if you face any issues on older ios versions IOS8 and less.
xamarin forms RTL master details page with icon RTL/LTR hamburger
You can make it by ToolbarItems in Xamarin Forms
ToolbarItems will appear in right side.
You can find more info from the following links :
http://codeworks.it/blog/?p=232