I've run into a simple problem, that I can not solve even after looking everywhere..
I made a grey table view, and at the top I have a cell with white background.
Is it possible to whenever the user refreshes, make it also white (on the top)?
Try this code
let refresh = UIRefreshControl()
let backgroundColor = UIColor.red
refresh.backgroundColor = backgroundColor
refresh.addTarget(self, action: #selector(self.refreshs), for: .valueChanged)
tableView.addSubview(refresh)
var frame = tableView.bounds
frame.origin.y = -frame.size.height
let backgroundView = UIView(frame: frame)
backgroundView.autoresizingMask = .flexibleWidth
backgroundView.backgroundColor = backgroundColor // background color pull to refresh
tableView.insertSubview(backgroundView, at: 0)
Related
Update: Nov.6
Thanks to pointum I revised my question.
On 10.13, I'm trying to write a view snapshot function as general purpose NSView or window extension. Here's my take as a window delegate:
var snapshot : NSImage? {
get {
guard let window = self.window, let view = self.window!.contentView else { return nil }
var rect = view.bounds
rect = view.convert(rect, to: nil)
rect = window.convertToScreen(rect)
// Adjust for titlebar; kTitleUtility = 16, kTitleNormal = 22
let delta : CGFloat = CGFloat((window.styleMask.contains(.utilityWindow) ? kTitleUtility : kTitleNormal))
rect.origin.y += delta
rect.size.height += delta*2
Swift.print("rect: \(rect)")
let cgImage = CGWindowListCreateImage(rect, .optionIncludingWindow,
CGWindowID(window.windowNumber), .bestResolution)
let image = NSImage(cgImage: cgImage!, size: rect.size)
return image
}
}
to derive a 'flattened' snapshot of the window is what I'm after. Initially I'm using this image in a document icon drag.
It acts bizarrely. It seems to work initially - window in center, but subsequently the resulting image is different - smaller, especially when window is moved up or down in screen.
I think the rect capture is wrong ?
Adding to pointum's answer I came up with this:
var snapshot : NSImage? {
get {
guard let window = self.window, let view = self.window!.contentView else { return nil }
let inf = CGFloat(FP_INFINITE)
let null = CGRect(x: inf, y: inf, width: 0, height: 0)
let cgImage = CGWindowListCreateImage(null, .optionIncludingWindow,
CGWindowID(window.windowNumber), .bestResolution)
let image = NSImage(cgImage: cgImage!, size: view.bounds.size)
return image
}
}
As I only want / need a single window, specifying 'null' does the trick. Well all else fails, the docs, if you know where to look :o.
Use CGWindowListCreateImage:
let rect = /* view bounds converted to screen coordinates */
let image = CGWindowListCreateImage(rect, .optionIncludingWindow,
CGWindowID(window.windowNumber), .bestResolution)
To save the image use something like this:
let dest = CGImageDestinationCreateWithURL(url, "public.jpeg", 1, nil)
CGImageDestinationAddImage(destination, image, nil)
CGImageDestinationFinalize(destination)
Note that screen coordinates are flipped. From the docs:
The coordinates of the rectangle must be specified in screen coordinates, where the screen origin is in the upper-left corner of the main display and y-axis values increase downward
Thank you for looking at my question. Currently, I have several input fields and a WKWebView embedded in a UIScrollView. Before any events fire, all the subviews fit inside the scroll view with no issue. I'm dynamically setting the WK's height based on document.body.scrollHeight which is captured in the DidFinishNavigation delegate located in WKNavigationDelegate. After the WK's height is set, the WK extends past the view-able content. Here's the code which I'm trying to force the scrollview to resize itself.
[Export("webView:didFinishNavigation:")] public async void DidFinishNavigation(WKWebView webView, WKNavigation navigation)
{
//get the webView's initial height
var initialHeight = webView.Frame.Height;
//get height of HTML's document.body.scrollHeight
var contentHeight = await GetContentHeight();
//create new frame for webview
CGRect newWebViewFrame = new CGRect(webView.Frame.X, webView.Frame.Y, webView.Frame.Width, contentHeight);
//set webview's frame
webView.Frame = newWebViewFrame;
//get the difference of webView's initial height and webView's current height
var differenceInHeight = contentHeight - initialHeight;
//create new cgrect and set the height to svMain's height + the difference in height of the HTML document
CGRect newScrollViewFrame = new CGRect(0, 0, svMainScroller.Frame.Width, svMainScroller.Frame.Height + differenceInHeight);
//set MainScroller's frame
svMainScroller.Frame = newScrollViewFrame;
//force scrolling
svMainScroller.ScrollEnabled = true;
//scrolling should be handled in the main scroller
webView.ScrollView.ScrollEnabled = false;
svMainScroller.SizeToFit();
}
The desired effect is to have the scroll view be able to scroll to the end of the newly defined height. Any tips on how would I go about doing that would be greatly appreciated.
Updating the frame of the scroll view was the problem. My guess is that if the frame is big enough to contain all of the contents, then there's no need to scroll. So, I updated the scroll view's ContentSize instead of updating its frame.
svMainScroller.ContentSize = new CGSize(View.Frame.Width, View.Frame.Height + differenceInHeight);
Also, as a side note, verify that wkwebview is added as a subview to the scroll view and not the main view.
I'm trying to programmatically set a background gradient like this in Xamarin iOS:
CGColor[] colors = new CGColor[] { new UIColor(red: 0.05f, green:0.44f, blue:0.73f, alpha:1.0f).CGColor,
new UIColor(red: 45/255, green: 128 / 255, blue: 153 / 255, alpha: 0.01f ).CGColor};
CAGradientLayer gradientLayer = new CAGradientLayer();
gradientLayer.Frame = this.View.Bounds;
gradientLayer.Colors = colors;
this.View.Layer.AddSublayer(gradientLayer);
And it works, but I have form elements on the screen (labels, buttons, etc) and this is causing all of them to appear faded, as if the layer appears directly on top of the elements. I think this is what the code is doing - it's rendering the entire page, and then adding the layer with opacity on top of the screen (I want it behind it instead).
What I'd like, instead, is to have the background set as gradient, but any elements I add will not be faded and try to match the background colors.
I tried adding a view on top of the standard view, and setting the alpha to 1, background to white, but that didn't seem to help (suggesting my theory that programmatically it's adding a layer on top of everything after it's rendered).
What am I doing wrong?
Thanks!
I know I am late for the show but for future reference, I use:
this.View.Layer.InsertSublayer(gradientLayer, 0);
The 0 represents index.
Your gradient layer that is assign to the root View of the ViewController is being displayed "behind" all the other Views.
By default, views (UILabel, UIButton, etc) do not have a background color set and thus will blend with that background layer, if that is not the effect that you are looking for assign a background to them:
var button = new UIButton(UIButtonType.System);
button.Frame = new CGRect(40, 300, 120, 40);
button.SetTitle("No Background", UIControlState.Normal);
button.TintColor = UIColor.Red;
View.AddSubview(button);
var button2 = new UIButton(UIButtonType.System);
button2.Frame = new CGRect(180, 300, 100, 40);
button2.SetTitle("Background", UIControlState.Normal);
button2.TintColor = UIColor.Red;
button2.BackgroundColor = UIColor.White;
View.AddSubview(button2);
I'm new with Xamarin. I'm actually trying to set the background image of a view and stretch it.
The image is a 2048x1536 pixels png.
nfloat vpHeight = View.Bounds.Height;
nfloat vpWidth = View.Bounds.Width;
Console.WriteLine(vpWidth);
Console.WriteLine(vpHeight);
The above code will return me 1024x768 (it's a landscape position).
var img = UIImage.FromFile("pages/p1.png");
UIImageView imgView = new UIImageView(img);
imgView.ContentMode = UIViewContentMode.ScaleAspectFit;
var prevPage = new UIView()
{
Frame = new CoreGraphics.CGRect(0, 0, vpWidth, vpHeight)
};
prevPage.Add(imgView);
this is the code where I set the background, but the result is just the half of the image in x and y just like the image bellow:
So, how to make the image to adjust to the width and height of the view ?
ty !!
I would create an UIImageView as a background like so:
var img = UIImage.FromFile("pages/p1.png");
UIImageView imgView = new UIImageView(img);
imgView.ContentMode = UIViewContentMode.ScaleAspectFit;
then add this to whatever view you are using.
ContentMode can be used like so:
Update
I would add it to the prevPage like so:
var prevPage = new UIView()
{
Frame = new CoreGraphics.CGRect(0, 0, vpWidth, vpHeight)
};
var img = UIImage.FromFile("pages/p1.png");
UIImageView imgView = new UIImageView(new CGRect(0,0,vpWidth,vpHeight));
imgView.Image = img;
imgView.ContentMode = UIViewContentMode.ScaleAspectFit; // or ScaleAspectFill
prevPage.Add(imgView);
Also its worth noting that using the View.Bounds to position the view is bit clunky. I would take a look into Autolayout as you will encounter problems on different devices and orientations. These are some good tutorials on Autolayout they might be native code but you are looking for the relationships of the views rather than the code.
Raywenderlich tutorial
Other Tutorial
Any probs with autolayout just ask another question.
I would recommend you stay away from FromPatternImage unless you are really using a pattern.
For the lowest memory consumption and best UI performance, this is what I do:
1st) Resize your image using an image context to match the size of the view:
UIGraphics.BeginImageContext(View.Frame.Size);
UIImage.FromBundle("bg.jpg").Draw(View.Bounds);
var bgImage = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
2nd) Display the resized image in a UIImageView and send it to the lowest Z-order:
var uiImageView = new UIImageView(View.Frame);
uiImageView.Image = bgImage;
View.AddSubview(uiImageView);
View.SendSubviewToBack(uiImageView);
I have Frame with Grid in content. When i added contentWiew (with content) to Grid there are two options:
1. If contentWiew have BackgroundColor = "Transparent" then when i click to the contentWiew pressing happen in Frame (contentWiew skiped through it).
2. If contentWiew have BackgroundColor = NotTransparent (Red,Yellow) then when i click to the contentWiew pressing happen in contentWiew ().
Part of the code:
Label mainText = new Label { Text = "TestText", FontSize = 14 };
var contntView = new ContentView () { BackgroundColor = Color.Transparent , HorizontalOptions = LayoutOptions.End, VerticalOptions = LayoutOptions.Start };
contntView.Content = mainText;
mainGrid.Children.Add (contntView,0,1);
I need to do exactly the turnover =) When ContentView is Transparent - catch click. When ContentView is not Transparent - skip click to Frame.
How can I control this process, regardless of BackgroundColor?
You can partially control this process using any View's InputTransparent property. If it's set to true, the view will be transparent to touch events.