I have a UITableView in a ViewController in a Storyboard (not a UITableViewController). What I want to do is add a custom UIView above the TableView in code. When the View is not there, the TableView's top anchor is anchored to PrimaryNavCollectionViewOutlet. I store this constraint as an outlet, and then if I have to add the View, I can use this outlet to remove the storyboard constraint.
I then constrain the inserted View to be below where the TableView was, and constraint the TableView to be below that.
Here's my code:
if (_viewAboveTableView != null)
{
TableView.RemoveConstraint(TableViewTopConstraint);
View.AddSubview(_viewAboveTableView);
_viewAboveTableView.TranslatesAutoresizingMaskIntoConstraints = false;
TableView.TranslatesAutoresizingMaskIntoConstraints = false;
_viewAboveTableView.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor).Active = true;
_viewAboveTableView.TopAnchor.ConstraintEqualTo(PrimaryNavCollectionViewOutlet.BottomAnchor).Active = true;
_viewAboveTableView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor).Active = true;
_viewAboveTableView.BottomAnchor.ConstraintEqualTo(TableView.TopAnchor).Active = true;
}
Unfortunately, when I run it, I can't see _viewAboveTableView. I feel like I'm missing something easy, but I can't figure out what. I've tried LayoutIfNeeded() and a few other methods on the View, but they don't make it appear. What have I missed?
Add height constraint to _viewAboveTableView.
Or
Make sure _viewAboveTableView has content that will specify intrinsic content size -- it should have properly laid-out subviews with content size (intrinsic or explicit via layouts. e.g. image, label etc.)
My guess is _viewAboveTableView is not getting inflated because it doesn't specify intrinsic content size (height > 0). If it's wrong constraints, you should be able to see it in the console.
It looks like the problem with what I was doing was that TableView.RemoveConstraint(TableViewTopConstraint); didn't have the intended effect.
From this answer I learned that RemoveConstraint is, or is about to be, deprecated in favour of TableViewTopConstraint.Active = false;. This made my code work the way that was intended.
I want to create a page which has a vertical but no horizontal scroll. It must adjust width of the content and vertical scroll automatically as per screen size.
Something similar to this:
I can not use UITableView since, my page may not have necessarily homogenous elements. It could have a combination of textfields , dropdown etc.
The previous answer was quite right, but not right at all. Indeed I tried to solve this problem using the method described before, but to make it work, I made some adjustments.
Your view's hierarchy has to be as follow :
UIScrollview :
View1
View2
View3
You don't need a container inside the UIScrollview, because apart the fact that it will be an extraview that you don't need, there is the problem that if you use this container-view you will get problem getting touch events in the views added.
So, let's make a step-by-step process:
Add scrollview to your viewController
The first step is to add the scrollview to your viewController, and we can simply do this programmatically in the following way:
UIScrollView scrollView = new UIScrollView();
scrollView.TranslatesAutoresizingMaskIntoConstraints = false;
View.AddSubview(scrollView);
View is the main-view of the viewController you are working in (aka Self.View).
Put attention to set TranslateAutoResizionMaskIntoConstrains property of the scrollview to false, otherwise autoresizing will mess your constraints.
Add constraint (autolayout) to your scrollView
You need to ensure that you layout will adjust for every different iPhone-screen, so simply use auotlayout to pin your scrollView to the viewController main-view (is the View used in the next code sample):
scrollView.TopAnchor.ConstraintEqualTo(View.TopAnchor, 0).Active = true;
scrollView.BottomAnchor.ConstraintEqualTo(View.BottomAnchor, 0).Active = true;
scrollView.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor, 0).Active = true;
scrollView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor, 0).Active = true;
In this way your scrollView is pinned to the bound of the main-view.
Create the view to be added
You need to create the view that you will add to the scrollView:
UIView viewToBeAdded = new UIView();
viewToBeAdded.TranslatesAutoresizingMaskIntoConstraints = false;
viewToBeAdded.Frame = new CGRect(0, 0, UIScreen.MainScreen.Bounds.Width, 200);
We have created a new UIView that setting its frame large as the screen (UIScreen.MainScreen.Bounds.Width) so it won't scroll horizontally, and with an arbitrary height (200 in the sample).
NOTE : even in this case you have to set TranslateAutoResizingMaskProperty to false, otherwise you will get a mess.
Add the view to the scrollView
Next step is to add our new view to the scrollView as follow:
scrollView.AddSubview(view);
Nothing more.
Set constraint for the view added in relation to the scrollView
Once you have added your view you have to said which will her behavior related to the scrollView. We assume that we will add several view to the scrollView, so we have to made a distinction, to the behavior of the FIRST view, the IN-BETWEEN views, and the LAST view.
So to be clear we assume that we are adding only 3 views, so we will have the three different cases.
FIRST VIEW
The important thing is that the first view has to be pinned to the top of the scrollView, we do this as follow :
firstView.TopAnchor.ConstraintEqualTo(scrollView.TopAnchor, 0).Active = true;
and then we set the others constraints:
firstView.WidthAnchor.ConstraintEqualTo(firstView.Bounds.Width).Active = true;
firstView.HeightAnchor.ConstraintEqualTo(firstView.Bounds.Height).Active = true;
IN-BETWEEN VIEW
The in between views (in our sample the secondView) need to be pinned to the previous view added (in our case the first view). So we do as follow:
secondView.TopAnchor.ConstraintEqualTo(firstView.BottomAnchor).Active = true;
So the top of the secondView is pinned to the bottom of the firstView.
And then we add the others constraints:
secondView.WidthAnchor.ConstraintEqualTo(secondView.Bounds.Width).Active = true;
secondView.HeightAnchor.ConstraintEqualTo(secondView.Bounds.Height).Active = true;
LAST VIEW
The last view (in our case the third view) instead needs to be pinned to the bottom of the previousView (in our case the secondView) and to the bottom of the scrollView.
thirdView.TopAnchor.ConstraintEqualTo(secondView.BottomAnchor).Active = true;
thirdView.BottomAnchor.ConstraintEqualTo(scrollView.BottomAnchor).Active = true;
And the usual other constraints for width and eight:
thirdView.WidthAnchor.ConstraintEqualTo(thirdView.Bounds.Width).Active = true;
thirdView.HeightAnchor.ConstraintEqualTo(thirdView.Bounds.Height).Active = true;
In this way the eight of the scrollView will adapt to the eight of the views added, due to the fact that the views inside are pinned to the top and the bottom of the scrollView.
CONCLUSIONS
If you follow these simple instruction you will get everything work. Remember to disable autoResizingMask, as this is on of the common mistake.
Hope it was helpful.
Cheers
In a custom renderer for Xamarin.Forms i've written my UITableViewController like this:
_controller = new InfoFieldItemsTableViewController();
_controller.TableView.SeparatorStyle = UITableViewCellSeparatorStyle.None;
_controller.TableView.SeparatorColor = UIColor.Clear;
_controller.TableView.AllowsSelection = false;
// http://useyourloaf.com/blog/self-sizing-table-view-cells/
_controller.TableView.RowHeight = UITableView.AutomaticDimension;
In my controller i am doing this to register all potential cell candidates:
private void RegisterCells()
{
foreach (var tuple in InfoFieldCellMapping.Map)
{
this.TableView.RegisterNibForCellReuse(tuple.Value.Item1, tuple.Value.Item2);
}
}
public override void ViewDidLoad()
{
RegisterCells();
base.ViewDidLoad();
}
I am doing this in my controller so cells resize themselves depending on how much height they need:
public override nfloat EstimatedHeight(UITableView tableView, NSIndexPath indexPath)
{
return 100;
}
Now all you need to do is create cell files from within your IDE which should be .xib files and design them in the editor using autolayout (so they can adapt to orientation changes automatically).
Within your TableViews datasource all that's left to do is mapping between your data item and it's corresponding cell similar to:
public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
{
var dataItem = Items[indexPath.Row];
var key = ""; // use info from data item to figure out which key identifies your table cell to dequeue the correct kind of cell
var cell = collectionView.DequeueReusableCell(key, indexPath) as UICollectionViewCell;
}
That's all you need really. In my scenario i am mapping fields which may contain different controls for date entries, number entries, long texts, short texts etc etc.
I hope that helps
1.Add Leading,Trailing,Top,Bottom Constraints on scrollView to it'superview.
2.Add UIView as containerView of scrollview and add 6 Constraints from containerView to scrollview as below.
a)Leading b)trailing c)top d)bottom e)Center Horizontally.
3.Make sure top elements in container view must bind to top by adding top constraints and also bind bottom most element to bottom of container view by adding bottom constraints.And also all the items between topmost and bottommost in the container view must be vertically connected to each other so it will define the content size of container view.
it will define the actual content height for scrollview.
and finally define content size for scrollview in code.
As I mentioned here .
Refer to Step 1 and Step 2 ,set constraints on Scrollview and containerView.
I remove the margin between Scrollview and View , and I add some controls on the containerView , so it looks like as below:
Notice
Since we set the containerView's width equal to scrollview's width, the width is fixed, so we can scroll vertically not horizontally.
Height of controls and spaces between them should be set clearly, because the contentSize is auto calculated by adding them. (If contentSize is greater than the height of screen ,the scrollview can be scrolled)
I saw you set those constrains on controls , but you can't scroll down to see the controls out of screen, I think you are missing to set bottom margin on the last control(the downmost one).
Let us do a test.
1. We set the margin (between button and textfield ) to 1000 and don't set bottom margin between the textfield and containerView.
Result : can't scroll down to see the textfield out of screen.
2. Set the margin 1000 and add a bottom margin(10) between textfiled and containerView.
Result: can scroll
Demo Link
I have a UIView with a side menu that comes from the left and pushes the right view from full with to a smaller size (full width - (menu width)).
Per someones suggestion I accomplish that effect by changing the constant in the constraint for the menu width: from 0 to 200.
The (right side view) UIView that's gonna hold the view that I will load to it has the constraints seen in this image (menu is on the left in blue):
I add the new UIView to the detailsView (container mentioned above) with the following code:
var viewNames = NSDictionary.FromObjectsAndKeys (new NSObject[] {
view.View
}, new NSObject[] {
new NSString ("detailsView")
});
detailsViewContainer.AddSubview (view.View);
view.View.TranslatesAutoresizingMaskIntoConstraints = false;
detailsViewContainer.AddConstraints (NSLayoutConstraint.FromVisualFormat ("H:|[detailsView]|", 0, new NSDictionary (), viewNames));
The problem is that the newly added view always has the full width (1024) when the menu is collapsed but also when the menu is expanded, pushing the view outside the app limits on the right.
Any help would be appreciated.
Thanks in advance!
Make the master view width constraint (add one if there is no) to be <= 1024 (not strict). I would do the following:
|H:|-0-menuView-masterView-0-|
and specify in designer the width constraint for masterView as Less or Equal 1024
and specify in designer the width constraint for menuView as equal to 200. Make an outlet for it and change dynamically in code with
animation from 200 to 0 and back when required.
where:
menuView is menu UIView
masterView is master UIView placeholder
when your menu (green view) is open width constraint will be equal 200:
as soon as you set constraint to 0 your view will resize the main placeholder (orange view) as well:
Please find storyboard sample by the following link:
https://dl.dropboxusercontent.com/u/19503836/Main.storyboard
If I use following code to create a UI using Vaadin,
#Override
protected void init(VaadinRequest request) {
HorizontalLayout horizontalLayout = new HorizontalLayout();
horizontalLayout.addComponent(new Label("Why am I not shown?"));
Button button = new Button("expanding button");
horizontalLayout.addComponent(button);
horizontalLayout.setExpandRatio(button, 1);
horizontalLayout.setWidth(100, Unit.PERCENTAGE);
setContent(horizontalLayout);
}
The label I added to horizontalLayout is not shown in the created UI. Why is that? What I expect to happen in this case is the label to take its required width and the button to take the rest of the width. But the label is not shown at all.
Please don't ask me why I want to expand the button. This is just a MCVE and my real UI is somewhat more complex.
The Button has undefined size by default. So space will be shared by the 100% sized Label (by default) with expand ratio of 0 and the excess space of the Button cell with expand ratio 1. So all space is given to the excess space of the button.
Set the Label to have a undefined size with label.setSizeUndefined() and will work as you expect.
Note that relative sized components can lost all his space when using a expand ratio.
For example:
HorizontalLayout horizontalLayout = new HorizontalLayout();
Label l1 = new Label("one");
Label l2 = new Label("two");
Label l3 = new Label("three");
horizontalLayout.addComponent(l1);
horizontalLayout.addComponent(l2);
horizontalLayout.addComponent(l3);
horizontalLayout.setExpandRatio(l2, 1);
Will show only label "two".
iPad - Popup
I have a popup and wish it to be 75% of the height and width of the screen. My screen is a UISplitView.
How is this done with UIPopoverController.PresentFromRect ?
I have tried many combos of values, but the results are 'strange'.
Note: I do not wish to use the PresentFromButton.
I figured it out.
1) You need o set the size of the popup:
myUIPopupController.PopoverContentSize = new SizeF (1024f, 1024f);
2) Then set the popup based on a relative frame size:
myUIPopupController.PresentFromRect (relativeFrame, this.SplitViewController.View, UIPopoverArrowDirection.Right, true);