How do you create a drop shadow on a button or label using Xamarin Forms. I am currently using Xamarin Forms 1.3 and trying to do this in XAML if possible. Does anyone have a working example they can point me to.
I have not tried this but you could create 2 instances of the same control and put them both inside a grid so that they lay directly over each other. Then with the first control (underneath) change the opacity to 0.2 so that it is very faint, then give it a small top and left margin so it sits slightly offset from the version above it. This should result in a drop-shadow type of effect.
A much better (but more involved) way of doing this is to subclass the controls you want to add the effect to and then create custom renderers to add the effect for each platform using native code
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I'm trying to do this animation in flutter :
https://material.io/guidelines/motion/choreography.html#choreography-creation
My problem is that I have absolutely no idea how to do that.
As far as I know, widgets in flutter don't know their position nor the position or other widgets at all.
And you can't access context.size inside the build method.
I tried to use Hero animation to do it. Or ScaleTransition. But it's definitely not working.
You can use showMenu to dynamically show a popup menu at a given location. Consider using PopupMenuButton, which is an IconButton that automatically shows a menu when it is tapped. There's an example in the Gallery. If showMenu doesn't do what you want, you can copy the code in popup_menu.dart and customize it to make your own version. It uses CustomSingleChildLayout and PopupRoute.
If you just want to absolutely position a Material or Card on top of other elements, you can give it some elevation and use a Positioned within a Stack. You can use an AnimatedSize to adjust the element's size with a Curve. This won't interact with the back button on Android automatically, so if you want that, you may have to use addLocalHistoryEntry or PopupRoute.
If I understand you correct - you want to show square widget, and animation is not suitable at most because widget doesn't know its size.
In this case you can try MediaQuery.of(context).size.width - it returns width of your screen, so you can use it for calculating widgets size
I have an app that displays properly in portrait view but truncates in landscape view:
From the research I have done it looks like I need to understand Size Classes and Adaptive Layout. However, I am only concerned with layout on iPhone 6, not across different devices (eg iPad).
Before jumping into Adaptive Layout and Size Classes, which seems quite a complex topic, I just wanted to ask if there is a simple way to make this app display properly in both portrait and landscape for iPhone 6.
Thanks in advance!
Yes, you can do it without size classes, but it requires a reasonable modification to your UI.
If you think about it then having a picker always visible makes no sense for you. Looking at your image I am puzzled as to which date is currently being adjusted.
What you want to do instead, is to make your picker appear after user clicks on one of the dates. You can make it slide up from the bottom. In addition, you can add a label above it which will clearly indicate which date the user is currently modifying. That label can be placed in the toolbar to make it easy to add "Done" and "Cancel" buttons to the left and to the right.
In my view it would make much more sense and would also solve your problem. The rest of the UI can be put in the scroll view if you don't have enough space on old devices (e.g. 3.5 inch iPhones)
Is Autolayout needed to setup for any subview, if my application only support one orientation (e.g., landscape right), applied for all UIViewControllers?
Yes, of course in the case of using animation I agree. But for the normal case, do I need AutoLayout?
Note: I am using XCode7, Swift, ios9
Understanding Auto Layout
Auto Layout dynamically calculates the size and position of all the
views in your view hierarchy, based on constraints placed on those
views. For example, you can constrain a button so that it is
horizontally centered with an Image view and so that the button’s top
edge always remains 8 points below the image’s bottom. If the image
view’s size or position changes, the button’s position automatically
adjusts to match.
This constraint-based approach to design allows you to build user
interfaces that dynamically respond to both internal and external
changes.
Unless you are making an app for one specific screen size, you will want to
use Auto Layout.
Use cases:
You want to support different size classes.
You want to support different screen sizes.
The content displayed by the app changes.
The app supports internationalization.
The app supports Dynamic Type (iOS).
Most of these changes can occur at runtime, and they require a dynamic
response from your app. Others, like support for different screen
sizes, represent the app adapting to different environments. Even
through the screen size won’t typically change at runtime, creating an
adaptive interface lets your app run equally well on an iPhone 4S, an
iPhone 6 Plus, or even an iPad. Auto Layout is also a key component
for supporting Slide Over and Split Views on the iPad.
Auto layout is not required at all. Even for multiple orientations.
However, If you don't use it, you'll have to manage placement for all the different sized devices yourself. So you might as well use it.
I was reading Apple Watch Human Interface Guidelines and i'm curious if there is any way in displaying custom UI elements, other than those provided by default by Apple (like tables, buttons or labels). How did they managed to do this:
Did they use images?
While we haven't seen everything that Apple are doing with the core Watch OS apps, it is already clear there are many API functions that they are reserving for their own use at this stage. It's almost certain they were using some of those API functions to create these views.
There is no way to create truly custom UI elements with the current WatchKit API (i.e. entirely new custom classes doing custom drawing). That said, with some creativity, it would be possible to create most of the interface you depict with the current tools available to third party developers. This is almost certainly not the way Apple created it, but you could:
Create a group.
Put inside the group a button with a background image that represents one state of the coloured circle.
At runtime, visually animate the button image as needed by swapping through multiple images that rendered the various states of progress of the circle x colour options. Yes, the starting point would be thinking about 360 images for the circle states x the number of tints. (It is possible to apply a tint to a template image in WatchKit, but as far as I am aware you cannot apply a gradient.)
Add two labels to the group for the large number and subscript, and align both of these to be centred vertically and horizontally in the group.
You can set the tint of the page title at top left by setting the global tint of the application. By changing the global tint at runtime you could change these for each page.
It is not currently possible to change the colour of the page dots at the bottom. These are not set by the global tint and it is not possible currently to change these programatically.
Apple have indicated that later in 2015 third party developers will be able to build fully native apps, but even then, they have not given any indication of whether the API functionality available to us is broader, or whether our API will be essentially the same as it is now, with the one addition that at least some of the current WatchKit App Extension code will be able to run on the device when the iPhone is not present/charged.
I would like to make anchor points (handlers like in FabricJS) for change the size, width and height of any element drawn on layers with jCanvas. Is it possible to do that?
Previously, there was no easy way to create a resizable shape in jCanvas. However, I have recently released a jCanvas plugin, called Handles, that will allow you to do just that. You can download and read the documentation for Handles on its plugin page.