I am trying to setup a UICollectionView within my existing UIViewController. Everything is working except for getting a title to show for each section - I can't figure out what I'm doing wrong.
My code in the UIViewController to initiate the collection view:
public partial class ViewController : UIViewController
{
//...
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
CollectionView_Outlet.RegisterClassForCell(typeof(ModifierCell), ModifierCell.CellID);
CollectionView_Outlet.RegisterClassForSupplementaryView (typeof(Header), UICollectionElementKindSection.Header, Header.HeaderId);
CollectionView_Outlet.ShowsHorizontalScrollIndicator = false;
CollectionView_Outlet.Source = new ModifiersSource(this);
CollectionView_Outlet.BackgroundColor = UIColor.White;
CollectionView_Outlet.ReloadData();
}
//...
}
Then I have created a subclass of UICollectionViewSource:
public class ModifiersSource : UICollectionViewSource
{
ViewController senderVC;
public ModifiersSource(ViewController sender)
{
senderVC = sender;
}
public override nint NumberOfSections(UICollectionView collectionView)
{
return 2;
}
public override nint GetItemsCount (UICollectionView collectionView, nint section)
{
return senderVC.modifiers.Count;
}
public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
{
//...
}
public override UICollectionReusableView GetViewForSupplementaryElement(UICollectionView collectionView, NSString elementKind, NSIndexPath indexPath)
{
var headerView = (Header)collectionView.DequeueReusableSupplementaryView (elementKind, Header.HeaderId, indexPath);
headerView.Text = "Supplementary View";
return headerView;
}
}
And finally created:
public class Header : UICollectionReusableView
{
public static NSString HeaderId = new NSString("UserSource1");
UILabel label;
public string Text {
get {
return label.Text;
}
set {
label.Text = value;
SetNeedsDisplay ();
}
}
[Export ("initWithFrame:")]
public Header (RectangleF frame) : base (frame)
{
label = new UILabel (){
Frame = new RectangleF(0,0,300,50),
BackgroundColor = UIColor.Red};
AddSubview (label);
BackgroundColor = UIColor.White;
}
}
I've put a breakpoint on the GetViewForSupplementaryElement method but it never gets called. I've also set the following in my StoryBoard:
What am I missing?!
After many attempts of not being able to get the above to work, I manually set UICollectionViewFlowLayout whilst initiating the UIContainerView. Seems to have done the trick, but not sure why it didn't pick up the settings from my StoryBoard. Here is my working code:
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
CollectionView_Outlet.RegisterClassForCell(typeof(ModifierCell), ModifierCell.CellID);
CollectionView_Outlet.RegisterClassForCell(typeof(ItemOptionCell), ItemOptionCell.CellID);
CollectionView_Outlet.RegisterClassForSupplementaryView (typeof(Header), UICollectionElementKindSection.Header, Header.HeaderId);
CollectionView_Outlet.ShowsHorizontalScrollIndicator = false;
//This is the new bit I added:
var layout = new UICollectionViewFlowLayout ();
layout.HeaderReferenceSize = new CGSize (300, 40);
CollectionView_Outlet.SetCollectionViewLayout (layout, false);
CollectionView_Outlet.Source = new ModifiersSource(this);
CollectionView_Outlet.ReloadData();
}
To get this to work in Xamarin, I had to enable Section Header under accessories (and it crashed in Xamarin, so from XCode). I had to do this even though I'm loading my header from a separate nib/xib into my collection view (but it will also show a reusable cell on the collection view that I don't think I need). Very specific but hopefully this saves someone in a similar situation some time!
Related
I am using UICollectionView to store images and I can reorder them by overriding CanMove And MoveItem.
But the items inside the UICollection only reorder when cell size is large like if cell size is around 106 height and width, then they can be reordered if they are smaller in size, they are cannot be reordered.
View:
public override void ViewDidLoad()
{
base.ViewDidLoad();
//ImageCv is the name of UiCollectionView
var collectionLayout = new PostImageFlowLayout(3, 0.85f);
var allCollectionSource = new PostImageColectionSource(ImageCv, (ViewModel as NewPostDetailViewModel));
ImageCv.RegisterNibForCell(PostImageCell.Nib, PostImageCell.Key);
ImageCv.RegisterClassForSupplementaryView(typeof(CollectionHeader), UICollectionElementKindSection.Header, new NSString("headerId"));
ImageCv.BackgroundColor = UIColor.Clear;
ImageCv.Hidden = false;
ImageCv.DataSource = allCollectionSource;
ImageCv.Delegate = collectionLayout;
var longPressGesture = new UILongPressGestureRecognizer(gesture =>
{
// Take action based on state
switch (gesture.State)
{
case UIGestureRecognizerState.Began:
var selectedIndexPath = ImageCv.IndexPathForItemAtPoint(gesture.LocationInView(View));
if (selectedIndexPath != null)
ImageCv.BeginInteractiveMovementForItem(selectedIndexPath);
Debug.WriteLine("Gesture Recognition: Activated");
break;
case UIGestureRecognizerState.Changed:
ImageCv.UpdateInteractiveMovement(gesture.LocationInView(View));
Debug.WriteLine("Gesture activated: Item location is changed");
break;
case UIGestureRecognizerState.Ended:
ImageCv.EndInteractiveMovement();
Debug.WriteLine("Gesture activation: complete");
break;
default:
ImageCv.CancelInteractiveMovement();
Debug.WriteLine("Gesture activation: Terminate");
break;
}
});
// Add the custom recognizer to the collection view
ImageCv.AddGestureRecognizer(longPressGesture);
}
UICollectionViewDelegateFlowLayout
using System;
using System.Windows.Input;
using CoreGraphics;
using UIKit;
namespace Sources.CollectionSources
{
public class PostImageFlowLayout : UICollectionViewDelegateFlowLayout
{
private float headerHeight;
private int noOfItems;
private bool isLoading;
public PostImageFlowLayout(int noOfItems, float headerHeight = 0f)
{
this.noOfItems = noOfItems;
this.headerHeight = headerHeight;
}
public override CGSize GetSizeForItem(UICollectionView collectionView, UICollectionViewLayout layout, Foundation.NSIndexPath indexPath)
{
return GetPostCellSize();
}
public override CGSize GetReferenceSizeForHeader(UICollectionView collectionView, UICollectionViewLayout layout, nint section)
{
return new CGSize(collectionView.Frame.Width, headerHeight);
}
public override UIEdgeInsets GetInsetForSection(UICollectionView collectionView, UICollectionViewLayout layout, nint section)
{
return new UIEdgeInsets(0, 0, 0, 0);
}
private CGSize GetPostCellSize()
{
var relativeWidth = (UIScreen.MainScreen.Bounds.Width - 2) / this.noOfItems;
return new CGSize(relativeWidth, relativeWidth);
//return new CGSize(55, 55);
}
}
}
Source
public class PostImageColectionSource : MvxCollectionViewSource
{
private NewPostDetailViewModel newPostDetailViewModel;
private string type;
static NSString animalCellId = new NSString("PostImageCell");
static NSString headerId = new NSString("Header");
List<IAnimal> animals;
protected override NSString DefaultCellIdentifier
{
get
{
return PostImageCell.Key;
}
}
public override System.Collections.IEnumerable ItemsSource
{
get
{
return base.ItemsSource;
}
set
{
base.ItemsSource = value;
CollectionView.ReloadData();
}
}
public PostImageColectionSource(UICollectionView collectionView, NewPostDetailViewModel newPostDetailViewModel) : base(collectionView)
{
this.newPostDetailViewModel = newPostDetailViewModel;
animals = new List<IAnimal>();
for (int i = 0; i < 20; i++)
{
animals.Add(new Monkey(i));
}
}
public override nint NumberOfSections(UICollectionView collectionView)
{
return 1;
}
public override nint GetItemsCount(UICollectionView collectionView, nint section)
{
return 5;// animals.Count;
}
public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
{
var cell = (PostImageCell)collectionView.DequeueReusableCell(animalCellId, indexPath);
var animal = animals[indexPath.Row];
cell.Result(indexPath.Row);
return cell;
}
public override bool CanMoveItem(UICollectionView collectionView, NSIndexPath indexPath)
{
Debug.WriteLine("Ready to move images");
//System.Diagnostics.Debug.WriteLine("Checking if it can move the item");
return true;
}
public override void MoveItem(UICollectionView collectionView, NSIndexPath sourceIndexPath, NSIndexPath destinationIndexPath)
{
//base.MoveItem(collectionView, sourceIndexPath, destinationIndexPath);
Debug.WriteLine("Start moving images to reorder");
var item = animals[(int)sourceIndexPath.Item];
animals.RemoveAt((int)sourceIndexPath.Item);
animals.Insert((int)destinationIndexPath.Item, item);
}
}
When the GetPostCellSize in PostImageFlowLayout has width and height of around 100, the CanMove and MoveItem in PostImageColectionSource are being called and items are being reordered. But if the GetPostCellSize has width and height of around 50 or 70, even though the gestures are activated, CanMove and MoveItem in PostImageColectionSource are not being called hence cannot be moved.
Can anyone hope me with reordering the images in UICollectionView when the cell size is small like around width and height of 70.
Thank you.
I am tagging swift and objective-C as this issue is related to IOS in general and not xamarin specific
Main issue here is that you need to pass in the collection view to the gesture.LocationInView(View) call instead of the main View. In ViewDidLoad in the UILongPressGestureRecognizer change:
var selectedIndexPath = ImageCv.IndexPathForItemAtPoint(gesture.LocationInView(View));
and
ImageCv.UpdateInteractiveMovement(gesture.LocationInView(View));
to
var selectedIndexPath = ImageCv.IndexPathForItemAtPoint(gesture.LocationInView(ImageCv)); // <-- pass in ImageCV instead of View. (where ImageCV is the collection view)
and
ImageCv.UpdateInteractiveMovement(gesture.LocationInView(ImageCv)); // <-- pass in ImageCV instead of View.
Another thing to note, but not a huge deal, is that PostImageColectionSource is ultimately derived from UICollectionViewSource, which is a combo of UICollectionViewDelegate and UICollectionViewDataSource in one class, but is being assigned to the DataSource property of the collection view. All this means is that though you can implement methods for UICollectionViewDelegate in PostImageColectionSource the delegate methods will not be called on that class since the Delegate property of the collection view is set to the PostImageFlowLayout, which derives ultimately from UICollectionViewDelegate via UICollectionViewDelegateFlowLayout.
I am trying to build an self-sizing UITableView Cell. After googled, I found this tutorial: https://pontifex.azurewebsites.net/self-sizing-uitableviewcell-with-uitextview-in-ios-8/ which is quite good.
In swift, it's saying that tableView?.BeginUpdates can update the size of the custom cell. But It seems not working in xamarin ios.
Could someone help me on that? Many Thanks!
using System;
using Foundation;
using UIKit;
using CoreGraphics;
namespace Ma
{
public partial class DataInput : UITableViewCell
{
public string title { get; set;}
public static readonly UINib Nib = UINib.FromName ("DataInput", NSBundle.MainBundle);
public static readonly NSString Key = new NSString ("DataInput");
public string value { get; set;}
public DataInput (IntPtr handle) : base (handle)
{
}
public static DataInput Create ()
{
return (DataInput)Nib.Instantiate (null, null) [0];
}
public void Populate()
{
this.Title.Text = this.title;
if (!string.IsNullOrEmpty(value)) {
this.Input.Text = this.value;
}
}
public string GetInputValue()
{
return this.Input.Text;
}
public UITableView GetTableView()
{
UITableView table = null;
UIView view = this.Superview;
if (view != null) {
table = (UITableView)view.Superview;
}
return table;
}
public override void AwakeFromNib ()
{
base.AwakeFromNib ();
this.Input.ScrollEnabled = false;
this.Input.Delegate = new DataInputDelegate ();
}
public override void SetSelected (bool selected, bool animated)
{
base.SetSelected (selected, animated);
if (selected) {
this.Input.BecomeFirstResponder ();
} else {
this.Input.ResignFirstResponder ();
}
}
}
public partial class DataInputDelegate : UITextViewDelegate
{
public override void Changed (UITextView textView)
{
var size = textView.Bounds.Size;
var newSize = textView.SizeThatFits (new CGSize (size.Width, size.Height));
if (size.Height != newSize.Height) {
UITextView.AnimationsEnabled = false;
UITableViewCell input = (UITableViewCell)textView.Superview.Superview;
UITableView tableView = (UITableView)input.Superview.Superview;
// This is the place of updating custom cell size, but It's not working now.
tableView.BeginUpdates ();
tableView.EndUpdates ();
UITextView.AnimationsEnabled = true;
var thisIndexPath = tableView.IndexPathForCell (input);
tableView.ScrollToRow (thisIndexPath, UITableViewScrollPosition.Bottom, false);
}
}
}
}
BTW, I am using autolayout and set
TableView.EstimatedRowHeight = 50;
TableView.RowHeight = UITableView.AutomaticDimension;
And I have done the following setting as well.
public override nfloat GetHeightForRow(UITableView tableView, NSIndexPath indexPath)
{
if (indexPath.Row == 0) {
return 80.0f;
}
return UITableView.AutomaticDimension;
}
Many thanks if someone can guide me!
Based on constraints placed on view, then autolayout will work. The code works fine after I set up the constraints of each components.
I am trying to make a custom TableView that has big heights, but when i run it i can only access 2 of my 5 rows in the table(in the example i provided)
Here is a screen shot of how i am viewing my table : http://i.imgur.com/1dsPNj5.png
Here is the link to my Table Source : http://pastebin.com/B7U2BEd8
Here is my view controller :
unclass[] lol= new unclass[amount];
for (nint i = 0; i < amount; i++) {
lol [i] = new unclass ();
Console.WriteLine ("item created");
}
UITableView _table;
_table = new UITableView{ Frame = new CoreGraphics.CGRect (0, 30, View.Bounds.Width, 3000),Source= new TableSource(lol) };
_table.SeparatorStyle = UITableViewCellSeparatorStyle.None;
for (nint i = 0; i < amount; i++) {
lol [i].imager = await this.LoadImage (links[i]); //loads image from the net to table
}
View.AddSubview (_table);
}
I really don't understand why this is happening
Your TableSource is not the problem, I tested it with a blank table.
Also as Jason said you will need to change the table's frame height to "View.Bounds.Height - 30" -30 to compensate for your Y position. I created a simple example below that show all 5 cells. So it might be the way that you are adding the table or if there is anything else in the viewController. Are you able to post more of your view controller's code?
using UIKit;
using CoreGraphics;
using System;
using Foundation;
namespace SO_Xam_actvity
{
public class bigTableViewController : UIViewController
{
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
UITableView _table;
_table = new UITableView{ Frame = new CGRect (0, 30, View.Bounds.Width, View.Bounds.Height-30),Source= new TableSource(new [] {1,1,1,1,1}) };
_table.SeparatorStyle = UITableViewCellSeparatorStyle.None;
View.AddSubview (_table);
}
}
public class TableSource : UITableViewSource
{
int[] tableItems;
string cellIdentifier = bigTableViewCell.Key;
public TableSource (int[] items)
{
tableItems = items;
}
public override nint RowsInSection (UITableView tableview, nint section)
{
return tableItems.Length;
}
public override nfloat GetHeightForRow (UITableView tableView, NSIndexPath indexPath)
{
return 200;
}
public override UITableViewCell GetCell (UITableView tableView, NSIndexPath indexPath)
{
var cell = tableView.DequeueReusableCell (cellIdentifier) as bigTableViewCell;
if (cell == null) {
cell = new bigTableViewCell();
}
cell.DetailTextLabel.Text = $"{indexPath.Row}";
return cell;
}
}
public class bigTableViewCell : UITableViewCell
{
public static readonly NSString Key = new NSString ("bigTableViewCell");
public bigTableViewCell () : base (UITableViewCellStyle.Value1, Key)
{
TextLabel.Text = "TextLabel";
}
}
}
I've created a custom EntryElement for our MonoTouch.Dialog so that all the controls are aligned to the right. The code is as follows:
public class RightAlignEntryElement : EntryElement
{
private NSString _cellKey = new NSString("RightAlignedEntryElement");
public RightAlignEntryElement(string caption, string placeholder, string value) : base(caption, placeholder, value)
{
}
protected override UITextField CreateTextField(RectangleF frame)
{
var paddedFrame = frame;
paddedFrame.Width = frame.Width -= 10;
var textField = base.CreateTextField(paddedFrame);
textField.TextAlignment = UITextAlignment.Right;
return textField;
}
public override UITableViewCell GetCell(UITableView tv)
{
var cell = base.GetCell(tv);
return cell;
}
protected override NSString CellKey
{
get { return _cellKey; }
}
}
this works fine, until the Dialog gets refreshed, for example the table is scrolled, or subview is presented then dismissed.
Before there is padding on the right of the cell, and once scrolled the padding disappears. I've seen that this has been a problem is the past, and have seen various other suggestions on here and the Xamarin forums, but nothing seems to work for me.
See the attached screen grabs for before and after.
For the record, here is the response I got on another forum for this question:
The behaviour is due to not using the cell reuse in you RightAlignEntryElement
Your GetCell method should look something like:
public override UITableViewCell GetCell(UITableView tv)
{
var cell = tv.DequeueReusableCell (CellKey) as UITableViewCell;
if (cell == null) {
cell = base.GetCell(tv);
cell.TextLabel.Font = UIFont.FromName("HelveticaNeue-Light", 16);
}
return cell;
}
I have a tableView that contains a few UITextView controls. When the user taps on one of these the text inside should be selected so that any keyboard input immediately replaces the original content.
I cannot get the text inside a UITextView selected using this code:
txtQuantity.SelectAll (new NSObject(NSObjectFlag.Empty));
as this code only shows the menu "Select | Select All' without the text being actually selected.
Has someone gotten this to work?
EDIT:
The code below select the text inside the txtQuantity control, BUT ONLY IF the UIAlert is show first! Why is this?
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
txtQuantity.TouchDown += txtQuantityHandleTouchDown;
txtQuantity.EditingDidBegin += delegate {
txtQuantity.ExclusiveTouch=true;
UIAlertView uv = new UIAlertView("","OK",null,"OK",null);
uv.Show ();
};
}
void txtQuantityHandleTouchDown (object sender, EventArgs e)
{
txtQuantity.SelectAll (this);
txtQuantity.Selected = true;
}
If all code within the txtQuality.EditingBegin delegate is commented out, the HandleTouchDown event does not fire.
I am not sure that this is what you are going for but I put together a quick sample.
The problem I was having is with calling SelectAll in EditingDidBegin. I had to make a call to BeginInvokeOnMainThread to get the select to work. I am not sure if it is a problem with the event not happening on the main thread or you simply need to make an async call on the main thread.
using System;
using System.Collections.Generic;
using System.Linq;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
namespace SelectText
{
[Register ("AppDelegate")]
public partial class AppDelegate : UIApplicationDelegate
{
// class-level declarations
UIWindow window;
public override bool FinishedLaunching (UIApplication app, NSDictionary options)
{
// create a new window instance based on the screen size
window = new UIWindow (UIScreen.MainScreen.Bounds);
window.RootViewController = new MyTableViewController ();
// make the window visible
window.MakeKeyAndVisible ();
return true;
}
}
public class MyTableViewController : UITableViewController
{
public override void LoadView ()
{
base.LoadView ();
this.TableView.DataSource = new TableViewDataSource ();
}
private class TableViewDataSource : UITableViewDataSource
{
private class EditCell : UITableViewCell
{
UITextField _field;
public EditCell () : base (UITableViewCellStyle.Default, "mycell")
{
_field = new UITextField (this.Bounds);
_field.AutoresizingMask = UIViewAutoresizing.All;
_field.BackgroundColor = UIColor.Clear;
_field.ShouldReturn = delegate {
_field.ResignFirstResponder ();
return true;
};
_field.EditingDidBegin += delegate {
this.BeginInvokeOnMainThread ( delegate {
_field.SelectAll (this);
});
};
_field.Text = "Some Text";
this.Add (_field);
}
public override void LayoutSubviews ()
{
base.LayoutSubviews ();
_field.Frame = this.Bounds;
}
}
#region implemented abstract members of UITableViewDataSource
public override int RowsInSection (UITableView tableView, int section)
{
return 2;
}
public override UITableViewCell GetCell (UITableView tableView, NSIndexPath indexPath)
{
UITableViewCell cell = tableView.DequeueReusableCell ("mycell");
if (cell == null)
{
cell = new EditCell ();
}
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
return cell;
}
#endregion
}
}
}