How to set a static height and width for a UIImageView in xamarin iOS

Question

So i'm working on a CustomRenderer for a Picker in which i need an image to the right side of the picker, i was able to do that, but the image size is too big, how can i set a static size to it,

i tried doing this, but i'm not sure if i'm on the right track

 Control.BorderStyle = UITextBorderStyle.None;
                var downarrow = UIImage.FromBundle(element.PickerImageSource);
                Control.RightViewMode = UITextFieldViewMode.Always;
                var imgView = new UIImageView(downarrow);
                imgView.Frame = new CoreGraphics.CGRect(0.1, 0.1, 0.1, 0.1);
                Control.RightView = imgView;

any inputs would be helpful

Did you tried updating your CGRect parameters? like `new CoreGraphics.CGRect(0.1, 0.1, 20, 20);` — Dishant, Sep 17 '20 at 13:04
@Venky Hi, have a try with setting `ContentMode` for `UIImageView` to check whether it works. Such as: `imgView.ContentMode = UIViewContentMode.ScaleAspectFit;` — Junior Jiang, Sep 18 '20 at 08:46
@Venky Glad be helpful! If so, would you mind I update this as the answer? — Junior Jiang, Nov 19 '20 at 07:51
@Venky Okey, I have updated an answer. Please do not forget to accept it as answer( click the ✔ in the upper left corner of this answer) and vote it up, it will help others who have similar issue. — Junior Jiang, Nov 19 '20 at 08:10

score 1 · Accepted Answer · answered Nov 19 '20 at 08:09

There is a ContentMode property of UIImageView

Controls how the cached bitmap of a view must be rendered when the view's bounds change.

And from the ContentMode Enum, there is a ScaleAspectFit to make the image fits the frame of UIImageView.

Scales the contents so that everything is visible, while preserving the aspect ration. Any areas that are not filled become transparent.

Therefore, you can modify code by adding this property:

Control.BorderStyle = UITextBorderStyle.None;
var downarrow = UIImage.FromBundle(element.PickerImageSource);
Control.RightViewMode = UITextFieldViewMode.Always;
var imgView = new UIImageView(downarrow);
imgView.Frame = new CoreGraphics.CGRect(0.1, 0.1, 0.1, 0.1);

// modify here
imgView.ContentMode = UIViewContentMode.ScaleAspectFit;

Control.RightView = imgView;

This is only working prior iOS v13 – Arvis Mar 16 '22 at 00:03 — Arvis, Mar 16 '22 at 00:03

score 1 · Answer 2 · answered Aug 19 '21 at 21:43

1

UIViewContentMode.ScaleAspectFit did not work for me... However, I came up with another solution:

var template = new UIView();
template.Frame = new CGRect(0, 0, 20, 20);

var image = new UIImageView();
image.Frame = new CGRect(0, 0, 20, 20);
image.Image = UIImage.FromBundle("ic_caret_down");
template.AddSubview(image);

Control.RightViewMode = UITextFieldViewMode.Always;
Control.RightView = template;

answered Aug 19 '21 at 21:43

Aaron Ramos

87
3

This is the correct answer for iOS 13+. Starting in iOS 13, the implementation of leftViewRect(forBounds:) and rightViewRect(forBounds:) now ask the view for its systemLayoutSizeFitting(:). To achieve the previous behavior when linking against and running on iOS 13, add explicit sizing constraints on the view, wrap it in a plain UIView. – Arvis Mar 16 '22 at 00:07

How to set a static height and width for a UIImageView in xamarin iOS

2 Answers2