How to load image onto a button in xamarin forms PCL? - xamarin

I am picking a photo from photo library and i get the following
AlbumPath:
assets-library://asset/asset.JPG?id=106E99A1-4F6A-45A2-B320-B0AD4A8E8473&ext=JPG
Path:
/Users/myname/Library/Developer/CoreSimulator/Devices/21CB035B-A738-4F74-B121-2DB2A6B5372A/data/Containers/Data/Application/3081A323-98AF-4EF6-95B9-29D4C2CD8425/Documents/temp/IMG_20170408_111143.jpg
How do i assign this image to a button ? I tried the following.
var file = await CrossMedia.Current.PickPhotoAsync(
new Plugin.Media.Abstractions.PickMediaOptions
{
});
Button btn = new Button();
btn.Image = (Xamarin.Forms.FileImageSource)ImageSource.FromFile(file.Path);
No image is displayed on the button. Any help help is appreciated.
Thank you.

Once you deploy the application the app will not have access to your mac. For the application to use the picture it will need to be a bundled resource within the iOS application. Below is a simple example of using images within an iOS app. You'll definitely want to consider just adding a gesture listener to your image instead of making it a button though. If you try to just use the image on a button you'll have to do some styling adjustments to get it to look clean.
Image Setup
Put image in iOS Resource folder
Make sure bundledresource is selected from image properties.
Image Button
public class ImageButton : ContentPage
{
private Button _imageBtn = new Button { Image = "icon.png", Text = "Sample button" };
public ImageButton()
{
Content = new StackLayout
{
Children =
{
_imageBtn
}
};
}
}
Image with TapGesture
public class ImageButton : ContentPage
{
private Image _imageBtn = new Image { Source = "icon.png" };
private TapGestureRecognizer _imageTap = new TapGestureRecognizer();
public ImageButton()
{
_imageBtn.GestureRecognizers.Add(_imageTap);
Content = new StackLayout
{
Children =
{
_imageBtn
}
};
_imageTap.Tapped += (s, e) =>
{
// handle the tap
};
}
}

Related

FontAwesome icon with normal text in Xamarin

I want to make a button that has a small icon (from FontAwesome) and text on it in my Xamarin app. I know I can just make a button but the problem is that I will require two fonts (the standard font for text and FontAwesome for the icon). Would anyone happen to know how I can do this, or if there is another way to achieve what I want?
Thanks!
As the json mentioned, I just made a simple implementation.
Create a new class inherit from Label, set FormattedText to combine the string(standard and icon), and add tap gesture on it .
public class MyLabel : Label
{
public delegate void MyHandler(object sender, EventArgs e);
public event MyHandler myEvent;
public MyLabel(string _myIcon, string _myText)
{
//build the UI
FormattedString text = new FormattedString();
text.Spans.Add(new Span { Text = _myIcon ,FontFamily= "FontAwesome5Free-Regular" });
text.Spans.Add(new Span { Text = _myText, TextColor = Color.Red ,BackgroundColor = Color.Blue });
FormattedText = text;
//tap event
TapGestureRecognizer tap = new TapGestureRecognizer();
tap.Tapped += (sender,e) => {
myEvent(sender,e);
};
}
}
Usage
MyLabel label = new MyLabel("", "test");
label.myEvent += (sener,e) =>
{
//do something when tapping
};
Content = label;
For how to integrate FontAwesome in Xamarin.Forms ,refer to
https://montemagno.com/xamarin-forms-custom-fonts-everywhere/.

Create ContentPage template with fixed view on top

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);

Background image with Carousel effect

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.

Master Detail Page on the right side using Xamarin.Forms

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

How can I create a drawer / slider menu with Xamarin.Forms?

How do I create an a slider menu using Xamarin.Forms? Is it baked in or something custom?
You create a new class which contains all the definitions for both the Master - i.e. the menu - and the Detail - i.e. the main page. I know, it sounds back-to-front, but for example..
using System;
using Xamarin.Forms;
namespace testXamForms
{
public class HomePage : MasterDetailPage
{
public HomePage()
{
// Set up the Master, i.e. the Menu
Label header = new Label
{
Text = "MENU",
Font = Font.BoldSystemFontOfSize(20),
HorizontalOptions = LayoutOptions.Center
};
// create an array of the Page names
string[] myPageNames = {
“Main”,
“Page 2”,
“Page 3”,
};
// Create ListView for the Master page.
ListView listView = new ListView
{
ItemsSource = myPageNames,
};
// The Master page is actually the Menu page for us
this.Master = new ContentPage
{
Title = "The Title is required.",
Content = new StackLayout
{
Children =
{
header,
listView
},
}
};
// Define a selected handler for the ListView contained in the Master (ie Menu) Page.
listView.ItemSelected += (sender, args) =>
{
// Set the BindingContext of the detail page.
this.Detail.BindingContext = args.SelectedItem;
Console.WriteLine("The args.SelectedItem is
{0}",args.SelectedItem);
// This is where you would put your “go to one of the selected pages”
// Show the detail page.
this.IsPresented = false;
};
// Set up the Detail, i.e the Home or Main page.
Label myHomeHeader = new Label
{
Text = "Home Page",
HorizontalOptions = LayoutOptions.Center
};
string[] homePageItems = { “Alpha”, “Beta”, “Gamma” };
ListView myHomeView = new ListView {
ItemsSource = homePageItems,
};
var myHomePage = new ContentPage();
myHomePage.Content = new StackLayout
{
Children =
{
myHomeHeader,
myHomeView
} ,
};
this.Detail = myHomePage;
}
}
}
It is built in: MasterDetailPage. You'd set the Detail and Master properties of it to whatever kinds of Pages you'd like. I found Hansleman.Forms to be quite enlightening.
My minimum example (as posted here) is as follows:
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;
}
}
An example solution is hosted on GitHub.
On iOS the result looks like this (left: menu open, right: after clicking on "B"):
Note that you need to add the menu icon as a resource in your iOS project.
If you are looking for simple example of MasterDetailPage please have a look at my sample repo at GitHub. Very nice example is also presented here
Slideoverkit is a great plugin available for Xamarin Forms. There is a github to see free samples and you could find documentation about it here.

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