I'm trying to get 2 VBoxes up in my gtk# application. The problem is, they are not showing up at all. I cannot see the button. What am I doing wrong?
using System;
using Gtk;
using Kassa;
public partial class MainWindow : Gtk.Window
{
VBox left, right;
public MainWindow() : base(Gtk.WindowType.Toplevel)
{
Build();
this.Title = "Kassa";
this.SetSizeRequest(1920, 1080);
//this.Fullscreen();
left = new VBox();
left.HeightRequest = this.HeightRequest;
right = new VBox(true, 0);
right.HeightRequest = this.HeightRequest;
right.WidthRequest = 64 * 4;
Button button = new Button("b");
right.Add(button);
right.PackStart(button, true, false, 0);
button.Show();
this.Add(left);
this.Add(right);
right.Show();
this.ShowAll();
}
protected void OnDeleteEvent(object sender, DeleteEventArgs a)
{
Application.Quit();
a.RetVal = true;
}
}
I have tried every possible combination of Add and ShowAll I can think of.
You should use Window.Add() just once, to add the containing widget (a VBox or similar), and then employ the Box.PackStart() and Box.PackEnd() methods within that container in order to create complex layouts.
Build();
this.Title = "Kassa";
VBox container = new VBox();
left = new VBox();
right = new VBox(true, 0);
Button button = new Button( "b" );
right.Add(button);
right.PackStart( button, true, false, 0 );
container.PackStart( left, true, true, 5 );
container.PackStart( right, true, true, 5 );
this.Add( container );
this.ShowAll();
If you had added the boxes in reverse order, you would see a giant button occupying the whole screen. The explanation is that Window.Add() just adds one item, if you call it twice, then the former is forgotten, and the latter used... exactly the one that had nothing (the former had a button), creating the illusion that nothing was being shown.
Hope this helps.
Related
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);
I would like to create a layout with a fullscreen background image and some UI elements on top of it. The twist is this:
I would like the background image to swipeable like a carousel, but I would like the UI elements to stay in place. That is if I swipe the screen, the background image should slide to the side and a new image should replace it. I know about CarouselPage, but it seems to me that it won't do the trick, since a Page can have only one child which it replaces on swipe, meaning that the UI elements would be descendants of the CarouselPage and therefore would also be animated.
I am guessing I need some sort of custom renderer here, but how should I go about designing it? Should it be one fullscreen Image control replaced be another fullscreen Image control with the UI elements on top of it? And how can I do this? Or is there an all together better approach?
I am developing for iOS and Android using Xamarin.Forms.
Thanks in advance.
I don't like repeating myself much, and I think that multiple layers of actionable items can lead to confusion, but the problems appeals to me and I can see a niche for this kind of UI, so here's my take on your question.
Let's assume this is the (Xamarin.Forms.)Page you want to render with a custom carousel background:
public class FunkyPage : ContentPage
{
public IList<string> ImagePaths { get; set; }
public FunkyPage ()
{
Content = new StackLayout {
VerticalOptions = LayoutOptions.Center,
HorizontalOptions = LayoutOptions.Center,
Spacing = 12,
Children = {
new Label { Text = "Foo" },
new Label { Text = "Bar" },
new Label { Text = "Baz" },
new Label { Text = "Qux" },
}
};
ImagePaths = new List<string> { "red.png", "green.png", "blue.png", "orange.png" };
}
}
The renderer for iOS could look like this:
[assembly: ExportRenderer (typeof (FunkyPage), typeof (FunkyPageRenderer))]
public class FunkyPageRenderer : PageRenderer
{
UIScrollView bgCarousel = new UIScrollView (RectangleF.Empty) {
PagingEnabled = true,
ScrollEnabled=true
};
List<UIImageView> uiimages = new List<UIImageView> ();
protected override void OnElementChanged (VisualElementChangedEventArgs e)
{
foreach (var sub in uiimages)
sub.RemoveFromSuperview ();
uiimages.Clear ();
if (e.NewElement != null) {
var page = e.NewElement as FunkyPage;
foreach (var image in page.ImagePaths) {
var uiimage = new UIImageView (new UIImage (image));
bgCarousel.Add (uiimage);
uiimages.Add (uiimage);
}
}
base.OnElementChanged (e);
}
public override void ViewDidLoad ()
{
Add (bgCarousel);
base.ViewDidLoad ();
}
public override void ViewWillLayoutSubviews ()
{
base.ViewWillLayoutSubviews ();
bgCarousel.Frame = View.Frame;
var origin = 0f;
foreach (var image in uiimages) {
image.Frame = new RectangleF (origin, 0, View.Frame.Width, View.Frame.Height);
origin += View.Frame.Width;
}
bgCarousel.ContentSize = new SizeF (origin, View.Frame.Height);
}
}
This was tested and works. Adding a UIPageControl (the dots) is easy on top of this. Autoscrolling of the background is trivial too.
The process is similar on Android, the overrides are a bit different.
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
In my app I want to display a simple string within a popup when the user clicks on an image. For this I added a Tap gesture listener to the image and within the handler I have the following code:
private void GestureListener_Tap( object sender, GestureEventArgs e )
{
var img = sender as Image;
if( img == null ) {
return;
}
Point pos = e.GetPosition( img );
string text = "I'm a popup!";
var popup = new Popup() {
Child = new Border() {
BorderBrush = new SolidColorBrush( Colors.LightGray ),
Child = new TextBlock() {
Text = text,
TextWrapping = TextWrapping.Wrap,
},
},
HorizontalAlignment = HorizontalAlignment.Stretch,
HorizontalOffset = pos.X,
VerticalOffset = pos.Y,
Visibility = Visibility.Visible,
};
popup.IsOpen = true;
Debug.WriteLine( "GestureListener_Tap: " + text );
}
The call to WriteLine prints in the debugger output window but the popup doesn't get displayed. What am I doing wrong here?
Thanks for your help!
I tried your code and the Popup is displayed. I think the problem for you is the Position for the Image relative to the Mouse. Try to set another Background for the Parent Container and I think you'll see the Popup. You can also try to play around with
Point pos = e.GetPosition(null);
until you get the Position you require
I'm new to Windows Forms, in my project, i need to change the image in the picture box at runtime. I'm able to do that with the help of a timer. The picture just gets changed. Is it possible to do some transitions when image changes, for example fade in, fade out, blur etc.. If possible could some one please let me know how to do it. I searched in net but in vain.Thanks in advance.
Varun
Simply take new code file and paste below code in it
an original answer for the similar question, answer taken from another question
Answer
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;
public class BlendPanel : Panel
{
private Image mImg1;
private Image mImg2;
private float mBlend;
public BlendPanel()
{
SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer, true);
}
public Image Image1
{
get { return mImg1; }
set { mImg1 = value; Invalidate(); }
}
public Image Image2
{
get { return mImg2; }
set { mImg2 = value; Invalidate(); }
}
public float Blend
{
get { return mBlend; }
set { mBlend = value; Invalidate(); }
}
protected override void OnPaint(PaintEventArgs e)
{
if (mImg1 == null || mImg2 == null)
e.Graphics.FillRectangle(new SolidBrush(this.BackColor), new Rectangle(0, 0, this.Width, this.Height));
else
{
Rectangle rc = new Rectangle(0, 0, this.Width, this.Height);
ColorMatrix cm = new ColorMatrix();
ImageAttributes ia = new ImageAttributes();
cm.Matrix33 = mBlend;
ia.SetColorMatrix(cm);
e.Graphics.DrawImage(mImg2, rc, 0, 0, mImg2.Width, mImg2.Height, GraphicsUnit.Pixel, ia);
cm.Matrix33 = 1F - mBlend;
ia.SetColorMatrix(cm);
e.Graphics.DrawImage(mImg1, rc, 0, 0, mImg1.Width, mImg1.Height, GraphicsUnit.Pixel, ia);
}
base.OnPaint(e);
}
}
Build your project. You can now drop a BlendPanel from the top of the toolbox onto your form. Here's a sample program that uses it:
private float mBlend;
private int mDir = 1;
public int count = 0;
public Bitmap[] pictures;
public void myPhoto()
{
pictures = new Bitmap[9];
pictures[0] = new Bitmap(#"Library Images\cf3.jpg");
pictures[1] = new Bitmap(#"Library Images\cf4.jpg");
pictures[2] = new Bitmap(#"Library Images\l1.JPG");
pictures[3] = new Bitmap(#"Library Images\l2.JPG");
pictures[4] = new Bitmap(#"Library Images\l3.JPG");
pictures[5] = new Bitmap(#"Library Images\l4.JPG");
pictures[6] = new Bitmap(#"Library Images\l5.JPG");
pictures[7] = new Bitmap(#"Library Images\l6.JPG");
pictures[8] = new Bitmap(#"Library Images\l7.JPG");
timer1.Interval = 50; //time of transition
timer1.Tick += BlendTick;
try
{
blendPanel1.Image1 = pictures[count];
blendPanel1.Image2 = pictures[++count];
}
catch
{
}
timer1.Enabled = true;
}
private void BlendTick(object sender, EventArgs e)
{
mBlend += mDir * 0.02F;
if (mBlend > 1)
{
mBlend = 0.0F;
if ((count + 1) < pictures.Length)
{
blendPanel1.Image1 = pictures[count];
blendPanel1.Image2 = pictures[++count];
}
else
{
blendPanel1.Image1 = pictures[count];
blendPanel1.Image2 = pictures[0];
count = 0;
}
}
blendPanel1.Blend = mBlend;
}
You'll need to modify the new Bitmap(#"yourimagePath"); calls. Build and run. You should see the displayed image smoothly morph from your first image to your second image without any flickering.
I hope it helps for other...
There is no built-in support for such effects, but you can implement them. I'd suggest to write a custom control that renders the image and have a method for fade-swap, fade itself can be reached with alpha-blending drawing with .NET Graphics class.
However, Graphics class isn't very fast, I don't recommend to use this technique for big images. If you need some fancy UI with hw-accelerated effects, take a look at WPF.
Blend effects are easy to get going by using the ColorMatrix class. There's a good example available in my answer in this thread.
A simple way to get a blur is to resize the image, making it smaller, then redraw it back, making it larger. The Graphics.InterpolationMode property affects the type of blur you'll get.
Those are quicky do-it-yourself solutions. Any decent graphics library has these kind of operations built-in. You probably want something free, check out ImageMagick.NET
To put it simply, not without external (3rd-party) libraries.