Dynamic UI in Xamarin.Forms - xamarin.forms

I would like to add a scrollable menu to a mobile app page.Here Transfer, Accounts, Payment and Transaction are generated from an XML file.The rest is static layout.I am using Xamarin.Forms.I would like to know how to generate UI components dynamically and attach them to a placeholder using Xamarin.Forms.

Dynamic UI creation is simple like the people said and there are many examples. But i think the problem is creating your own control according to your needs. For example i ended up with writing my own button with image in it like this:
So you have to write a method that creates a vertical stack layout (lets say outer container),and add a horizontal container to that "outer container" (lets say inner container) than add an image and a label to this "inner container" and make "innerContainer.HorizontalOptions = LayoutOptions.Center" etc. If you want border it goes complicated :)
Vertical Stack (whole container)
->Vertical Stack (height 2px) upper border
->Horizontal Stack (to hold middle controls,left border,inner image and text holder, right border etc.)
->Horizontal Stack (width 2 px) left border
->Vertical Stack (layoutOptions=Fillandexpand)
->Image (layoutOptions=Center)
->Label (layoutOptions=Center)
->Horizontal Stack (width 2 px) right border
->Vertical Stack (height 2px) lower border
So you have to join the controls like this hierarcy. First think how can you draw your control with existing controls than code it :) Hope i made my self clear.

i think you can use "Collection View" which is new feature of xamarin.forms or "bindable layout" to make it dynamic.

Related

Dynamic chat bubble using autolayout

I am developing an application like iMessage.I would like to UI same like iMessage chat bubble work. I developed table view cell with auto layout.I have below table cell with UIImageView and UILabel.
UIImageView contain bubble image with resizableImageWithCapInsets. Right now everything is working fine except if text is small string then chat bubble is showing throughout the screen. so I would like to set constraints in such a way that my image view width will be according to label text. So if Label text is small then it will be small width image So it will be resizable according to width of label text. Any idea?
Current output:
.
I was thinking about my problem and researching on it and found below solutions. Posting it if it helps other.
So make it dynamic width based on text I put another blank label on right hand side and add constraints with it relative to left hand side controls(image view and label). Below is my final layout of constraints. Then it's working as expected.
Output Screen shot :

Add fixed sized items to grid layout in correct row

I am trying to create a grid layout of images kind of like how google images does it.
I want to add fixed sized images left to right, top to bottom but I am having trouble is figuring out when adding another image to a row would make it not fit and then decide that that images should be placed in a new row.
Also when the window resizes it should move images into/from rows based on how many it can fit in.
Ive got a scroll area with a grid layout in it which is fine if I know what can fit, but I can't figure out how to make it move items if say the window width is shrunk, and say an item needs to be moved down 1 row which moves other etc.
Assuming you are using QWidgets I'd suggest you to use QListView which does the layouting for free, if you want more control on how items are displayed use a QItemDelegate. For QListView the view mode should be set to QListView::IconMode so that you have a grid of items and not a list.
But if you are using QtQuick things are much easier, a GridView with Image delegates would do what you want really quickly and using GPU power to build you UI.

Creating auto-scaling Qt UI using Layouts

I'd appreciate advise on to how create a Qt UI consisting of four layouts and has the following properties.
Any increases in the height of the UI is absorbed by the layouts, as shown below
Any further decreases in the height of the UI is absorbed by the contents of a specific layout, e.g. the two large buttons as shown below
1# Create new UI form base on QWidget: File -> New file or project -> Qt -> Qt Designer form class -> select Widget form templates, next, next, select project and finish
2# Add Vertical layout from left bar
3# After that click right somewhere on UI form, where is not just added layout, "Lay out" -> "Lay out in a grid"
4# You can adjust layout margin on right menu (I'm always setting 5 points)
5# Add four Horizontal layout
6# Add Button and text and what you need
7# Add Vertical spacers between Horizontal layout
8# Final result:
I prepared quick code what fits your problem, please take a look: https://github.com/troyane/StackOverflow-pro/tree/master/creating-auto-scaling-qt-ui-using-layouts
Grab that code and take a look at next moments (you can open mainwindow.ui in QtCreator):
centralWidget has next layoutStretch param: 1,2,1,1 -- it means, that we'll have next correlation among all items placed into this vertical layout.
TextLabel and both SmallButtons has Fixed VerticalPolicy
Both BigButtons has Minimum vertical policy and set minimumSize's Height to 100. UPD: Also maximumSize->height parameter is 250 px. So, it is guarantee that both BigButtons will not grow more than 250 px on height.
Take a look at another answer, there you can find lots of literature to read about Layouts.
You can put two vertical spacers in each layout. One should be placed at top most and the other one at the bottom :

Resizing the superview according to the subviews

I have 3 subviews(UILabel, UIImageview, UIButton) to be laid out on a container view. All the subviews are laid out using visual format language (VFL). The subview have padding from the leading , top edges etc. The content of the subview are dynamic so their sizes changes all the time. i want to resize the superview(container view) to exactly fit all the subviews. Is this possible by auto layout? i have seen some of the link here which suggest intrinsic size which i am not able to understand. can someone suggest a better way to achieve this.
Yes, it's possible. If you plan to resize the superview according to subview content, then intrinsic content size is the way to go.
The ever excellent Ray Wenderlich site has a tutorial that covers this well. It's Beginning Auto Layout in iOS 6: Part 2/2:
Intrinsic Content Size
Before Auto Layout, you always had to tell buttons and other controls
how big they should be, either by setting their frame or bounds
properties or by resizing them in Interface Builder. But it turns out
that most controls are perfectly capable of determining how much space
they need, based on their content.
A label knows how wide and tall it is because it knows the length of
the text that has been set on it, as well as the font size for that
text. Likewise for a button, which might combine the text with a
background image and some padding for the rounded corners.
The same is true for segmented controls, progress bars, and most other
controls, although some may only have a predetermined height but an
unknown width.
This is known as the intrinsic content size, and it is an important
concept in Auto Layout. You have already seen it in action with the
buttons. Auto Layout asks your controls how big they need to be and
lays out the screen based on that information.
It is possible.
In my case, I wanted to give rounded corners to segmented control. For that, I embedded segmented control in UIView. Now I was required to resize that container view as per size of segmented control.
I gave only following constraint and everything was taken care itself.
(1) Chose container view and give it X and Y constraints.
Leading space to Super view.
Top space to Super view.
(2) Chose container view and give Leading | Trailing | Top | Bottom constraint.
Leading space to segmented control.
Top space to segmented control.
Trailing space to segmented control.
Bottom space to segmented control.
(3) Chose segmented control and give it Height and Width constraints.
Height : 30 // Whatever
Width : 250 // Whatever
Now if I change the height and width of my segmented control, it automatically adjust container view's size (super-view of segmented control).

How to layout out a component differently depending on the amount of space available?

I am trying to build a sort of button bar in Flex - something like the horizontally laid-out bookmark bar you'd see in most modern web browsers, where when you run out of horizontal space, you can click on the arrows button(>>) to get a drop-down to see the rest of the items which did not fit into the horizontal space. Problem is, how can I know how much horizontal space is available for me to tell how many buttons to render into the button bar? This need doesn't appear to be support by the general layout manager framework.
You can check the width of the parent container, and if that is less than the combined widths of your objects that you've attached with AddChild or AddElement, then you don't have enough space and need use your arrow functionality.

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