hello
for (int i = 1; i < terasmasasayisi; i++)
{
var buttonteras = new Button
{
Text = i.ToString(),
HeightRequest = 45,
WidthRequest = 45,
Margin = 5,
CornerRadius = 100,
};
buttonteras.Clicked += butonteras;
teras.Children.Add(buttonteras);
async void butonteras(object o, EventArgs args)
{
secilenmasa = buttonteras.Text;
secilenkonum = "Teras";
await Navigation.PushModalAsync(new menu());
}
}
i create multiple buttons in that way terasmasasayisi is counts how many row i have in database
and theese buttons directs me to another page on that page after clicking to a button i have to change the first buttons background color, how can i do that?
You could check the following code
Use MessagingCenter
for (int i = 1; i < 10; i++)
{
var buttonteras = new Button
{
Text = i.ToString(),
HeightRequest = 45,
WidthRequest = 45,
Margin = 5,
CornerRadius = 100,
};
buttonteras.Clicked += butonteras;
stack.Children.Add(buttonteras);
}
MessagingCenter.Subscribe<Object,View>(this,"click",(obj,view)=>
{
var childrens = stack.Children;
for (int i = 0; i < childrens.Count; i++)
{
var element = childrens[i];
var type = element.GetType();
if (element == view)
{
element.BackgroundColor = Color.Red;
}
}
});
async void butonteras(object o, EventArgs args)
{
//...
var button = o as Button;
await Navigation.PushModalAsync(new menu(button));
}
And in menu, when click button .
View Element;
public menu(View element)
{
Element = element;
InitializeComponent();
}
MessagingCenter.Send<Object,View>(this, "click",Element);
MessagingCenter.Subscribe<siparis>(this, "click", (obj) =>
{
var childrens = bahce.Children;
for (int i = 0; i < childrens.Count; i++)
{
var element = childrens[i];
var type = element.GetType();
if (element.GetType().ToString() == "Xamarin.Forms.Button")
{
element.BackgroundColor = Color.Red;
break;
}
}
});
async void bahcebuton(object o, EventArgs args)
{
secilenmasa = buttonbahce.Text;
secilenkonum = "Bahçe";
await Navigation.PushModalAsync(new menu());
}
and other form
if (masterpage.secilenkonum == "Bahçe")
{
MessagingCenter.Send<siparis>(this, "click");
}
now it doesnt makes all buttons red but now makes only first button red
Related
Xamarin Forms Custom Renderer iOS UICollectionView scrolling in both directions / horizontal – vertical scrolling
Intention: Implementation of an interactive Grid which scroll horizontally and vertically .
Problem:
The grid scrolls in both direction that much laggy. After scrolling with the finger you have to wait some seconds to see an reaction of the app.
We have implemented an UICollectionView in the same way in an native swift project, and it scrolls fluently. So I think the problem is rather the way of implementation than the rendering process.
With instruments I could find out that the CoreFoundation(RunLoops) cost the most of time(11s). So I guess its a threading problem.
Why I need to customize the UICollectionViewLayout to achieve horizontal scrolling? Because I need the ability to modify the width of single cells and other customizations too.
So the only way for scrolling in both direction I see, is to customize the UICollectionViewLayout.
Implementation:
Xamarin.Forms Project:
Create Custom Control (MyGrid) in Xamarin Forms, which extends from View Class:
public class MyGrid : View
{
public MyGrid() : base()
{
}
}
Use Custom Control ( MyGrid) in Xamarin Forms ContentPage):
<ContentPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:GridDemo"
x:Class="GridDemo.GridDemoPage">
<ContentPage.Content>
<local:MyGrid
VerticalOptions="FillAndExpand"
HorizontalOptions="FillAndExpand"
BackgroundColor="White"/>
</ContentPage.Content>
</ContentPage>
Xamarin.iOS Project:
Implement Custom Renderer for MyGrid Class in iOS project:
[assembly: ExportRenderer(typeof(MyGrid), typeof(MyGridRenderer))]
namespace GridDemo.iOS
{
public class MyGridRenderer : ViewRenderer<MyGrid, IOSGrid>
{
public MyGridRenderer()
{
}
protected override void OnElementChanged(ElementChangedEventArgs<MyGrid> e)
{
base.OnElementChanged(e);
if (Control == null)
{
MyGrid myGrid = (MyGrid)e.NewElement;
List<List<string>> values = myGrid.Source;
var list = new List<CustomIOSGridCell>();
var column = 0;
var row = 0;
var maxColumnLength = new int[myGrid.ColumnCount];
for (int i = 0; i < myGrid.RowCount; i++)
{
for (int j = 0; j < myGrid.ColumnCount; j++)
{
var array = values[i];
var stringLength = array.Aggregate("", (max, cur) => max.Length > cur.Length ? max : cur);
if (stringLength.Length > maxColumnLength[j])
{
maxColumnLength[j] = stringLength.Length;
}
list.Add(new CustomIOSGridCell(values[i][j));
}
}
var grid = new IOSGrid(this.Bounds, new IOSGridLayout(myGrid.ColumnCount, myGrid.RowCount, maxColumnLength));
grid.AddValues(list, myGrid.ColumnCount, myGrid.RowCount);
SetNativeControl(grid);
}
if (e.OldElement != null)
{
// Unsubscribe from event handlers and cleanup any resources
}
if (e.NewElement != null)
{
// Configure the control and subscribe to event handlers
}
}
}
}
Implement native control(iOSGrid), the corresponding Control to Custom Xamarin Forms Control (MyGrid):
public class IOSGrid : UICollectionView
{
List<CustomIOSGridCell> values = new List<CustomIOSGridCell>();
public IOSGrid(CGRect frame, IOSGridLayout collectionViewLayout) : base(frame, collectionViewLayout)
{
this.RegisterClassForCell(typeof(CustomCollectionViewCell), CustomCollectionViewCell.CellID);
BackgroundColor = UIColor.Blue;
}
public void AddValues(List<CustomIOSGridCell> values, int columncount, int rowCount)
{
this.values.AddRange(values);
this.Source = new CustomCollectionSource(this.values, rowCount, columncount);
this.ReloadData();
}
}
Implement Custom UICollectionViewLayout for IOSGrid(UICollectionView) to provide horizontal AND vertical scrolling
public class IOSGridLayout : UICollectionViewLayout
{
private Timer timer;
enum Direction { up, down ,leftRight, none }
int columnsCount = 0;
int rowCount = 0;
CoreGraphics.CGSize[] itemsSize = null;
CoreGraphics.CGSize contentSize = CoreGraphics.CGSize.Empty;
int[] maxLength;
public CGRect currentRect = CGRect.Empty;
CGPoint currentCorner = new CGPoint(-1, -1);
UICollectionViewLayoutAttributes[,] itemAttributes;
public IOSGridLayout(int columnsCount, int rowCount, int[] maxLength)
{
this.columnsCount = columnsCount;
this.rowCount = rowCount;
this.maxLength = maxLength;
itemAttributes = new UICollectionViewLayoutAttributes[rowCount, columnsCount];
}
public override void PrepareLayout()
{
if (CollectionView == null) return;
var collectionView = CollectionView;
if (collectionView.NumberOfSections() == 0) return;
if (itemAttributes.Length != collectionView.NumberOfSections())
{
generateItemAttributes(collectionView);
return;
}
for (int section = 0; section < collectionView.NumberOfSections(); section++)
{
for (int item = 0; item < collectionView.NumberOfItemsInSection(section); item++)
{
if (section != 0 && item != 0)
{
continue;
}
var attributes = LayoutAttributesForItem(NSIndexPath.FromItemSection(item, section)); }
}
}
public override CGSize CollectionViewContentSize
{
get { return contentSize; }
}
public override UICollectionViewLayoutAttributes LayoutAttributesForItem(NSIndexPath indexPath)
{
return itemAttributes[indexPath.Section, indexPath.Row];
}
public override UICollectionViewLayoutAttributes[] LayoutAttributesForElementsInRect(CGRect rect)
{
var attributes = new List<UICollectionViewLayoutAttributes>();
// calculate actual shown attributes
return attributes.ToArray();
}
public override bool ShouldInvalidateLayoutForBoundsChange(CGRect newBounds)
{
return true;
}
private void generateItemAttributes(UICollectionView collectionView)
{
if (itemsSize?.Length != columnsCount)
{
CalculateItemSizes();
}
var column = 0;
nfloat xOffset = 0;
nfloat yOffset = 0;
nfloat contentWidth = 0;
itemAttributes = new UICollectionViewLayoutAttributes[rowCount, columnsCount];
var se = collectionView.NumberOfSections();
for (int section = 0; section < rowCount; section++)
{
var sectionAttributes = new UICollectionViewLayoutAttributes[columnsCount];
for (int index = 0; index < columnsCount; index++)
{
var itemSize = itemsSize[index];
var indexPath = NSIndexPath.FromItemSection(index, section);
var attributes = UIKit.UICollectionViewLayoutAttributes.CreateForCell(indexPath);
attributes.Frame = new CGRect(xOffset, yOffset, itemSize.Width, itemSize.Height).Integral();
if (section == 0)
{
var frame = attributes.Frame;
frame.Y = collectionView.ContentOffset.Y;
attributes.Frame = frame;
}
if (index == 0)
{
var frame = attributes.Frame;
frame.X = collectionView.ContentOffset.X;
attributes.Frame = frame;
}
sectionAttributes[index]=attributes;
xOffset += itemSize.Width;
column += 1;
if (column == columnsCount)
{
if (xOffset > contentWidth)
{
contentWidth = xOffset;
}
column = 0;
xOffset = 0;
yOffset += itemSize.Height;
}
}
for (int i = 0; i < sectionAttributes.Length; i++)
{
itemAttributes[section, i] = sectionAttributes[i];
}
}
var attr = itemAttributes[rowCount-1,columnsCount-1];
if (attr != null)
{
contentSize = new CGSize(contentWidth, attr.Frame.GetMaxY());
}
}
private void CalculateItemSizes()
{
itemsSize = new CGSize[columnsCount];
for (int index = 0; index < columnsCount; index++)
{
itemsSize[index] = SizeForItemWithColumnIndex(index);
}
}
private CGSize SizeForItemWithColumnIndex(int index)
{
// CollectionView.CellForItem()
string text = "";
for (int i = 0; i < maxLength[index]; i++)
{
text += "M";
}
NSString ma = new NSString(text);
var size = ma.StringSize(UIFont.SystemFontOfSize(14));
size.Height = 35;
return size;
}
}
Implement Custom UICollectionViewSource for IOSGrid(UICollectionView):
public class CustomCollectionSource : UICollectionViewSource
{
private readonly List<CustomIOSGridCell> values = new List<CustomIOSGridCell>();
private readonly int rowCount = 0;
private readonly int columnCount = 0;
public CustomCollectionSource(List<CustomIOSGridCell> values, int rowCount, int columnCount)
{
this.values = values;
this.rowCount = rowCount;
this.columnCount = columnCount;
}
public override nint GetItemsCount(UICollectionView collectionView, nint section)
{
return rowCount;
}
public override nint NumberOfSections(UICollectionView collectionView)
{
return columnCount;
}
public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
{
var cell = (CustomCollectionViewCell)collectionView.DequeueReusableCell(CustomCollectionViewCell.CellID, indexPath);
cell.UpdateCell(values[indexPath.Row].Text);
return cell;
}
}
Implement Custom UICollectionViewCell for IOSGrid(UICollectionView):
public class CustomCollectionViewCell : UICollectionViewCell
{
public UILabel mainLabel;
public static NSString CellID = new NSString("customCollectionCell");
[Export("initWithFrame:")]
public CustomCollectionViewCell(CGRect frame) : base(frame)
{
// Default
ContentView.Layer.BorderColor = UIColor.Blue.CGColor;
ContentView.Layer.BorderWidth = 1.0f;
ContentView.Layer.BackgroundColor = UIColor.White.CGColor;
mainLabel = new UILabel();
ContentView.AddSubview( mainLabel );
}
public void UpdateCell(string text)
{
mainLabel.Text = text;
mainLabel.Frame = new CGRect(5, 5, ContentView.Bounds.Width, 26);
}
}
I have used Segmented Control in my application. I don't know how to add two content pages to Segment control like a tabbed page. I have attached the sample file. Please give any suggestion Link for Sample Application
Sample Code:
public partial class SamplePage : ContentPage
{
SegmentedControl segControl;
SegmentedControlOption optionOne;
SegmentedControlOption optionTwo;
public SamplePage()
{
segControl = new SegmentedControl();
optionOne = new SegmentedControlOption();
optionTwo = new SegmentedControlOption();
optionOne.Text = "One";
optionTwo.Text = "Two";
segControl.Children.Add(optionOne);
segControl.Children.Add(optionTwo);
var stack = new StackLayout()
{
VerticalOptions = LayoutOptions.StartAndExpand,
HorizontalOptions = LayoutOptions.CenterAndExpand,
Children = { segControl }
};
this.Content = stack;
}
}
ScreenShot Attached
Just some suggestions and explanations.
We can't put a ContentPage inside another ContentPage
It's better to use ContentView instead of ContentPage
Grid is more recommended in this scenario , since it fills with the whole Screen.
Use ValueChanged event to change the view dynamically.
Code :
Page
public partial class SegmentedAppPage : ContentPage
{
SegmentedControl segControl;
SegmentedControlOption scOptionOne;
SegmentedControlOption scOptionTwo;
Grid grid;
View1 view1 = new View1();
View2 view2 = new View2();
public SegmentedAppPage()
{
InitializeComponent();
segControl = new SegmentedControl();
segControl.SelectedValue = "One";
scOptionOne = new SegmentedControlOption();
scOptionTwo = new SegmentedControlOption();
scOptionOne.Text = "One";
scOptionTwo.Text = "Two";
segControl.Children.Add(scOptionOne);
segControl.Children.Add(scOptionTwo);
grid = new Grid();
grid.RowDefinitions.Add(new RowDefinition { Height = new GridLength(1, GridUnitType.Auto) });
grid.RowDefinitions.Add(new RowDefinition { Height = new GridLength(1, GridUnitType.Star) });
grid.Children.Add(segControl, 0, 0);
grid.Children.Add(view1, 0, 1);
this.Content = grid;
segControl.ValueChanged += SegControl_ValueChanged;
}
private void SegControl_ValueChanged(object sender, EventArgs e)
{
SegmentedControl control = sender as SegmentedControl;
if(control.SelectedValue is "One")
{
grid.Children.Remove(view2);
grid.Children.Add(view1,0,1); //This line
}
else if (control.SelectedValue is "Two")
{
grid.Children.Remove(view1);
grid.Children.Add(view2, 0, 1); //This line
}
this.Content = grid;
}
}
ContentView
public class View1 : ContentView
{
public View1()
{
Content = new StackLayout
{
BackgroundColor = Color.Green,
Children = {
new Label { Text = "View1" }
}
};
}
}
To set default value on segmentedControl , modify code in SegmentedControlRenderers
protected override void OnElementChanged(ElementChangedEventArgs<SegmentedControl> e)
{
base.OnElementChanged(e);
var segmentedControl = new UISegmentedControl();
for (var i = 0; i < e.NewElement.Children.Count; i++)
{
segmentedControl.InsertSegment(e.NewElement.Children[i].Text, i, false);
}
segmentedControl.ValueChanged += (sender, eventArgs) => {
e.NewElement.SelectedValue = segmentedControl.TitleAt(segmentedControl.SelectedSegment);
};
segmentedControl.SelectedSegment = 0; // add this line
SetNativeControl(segmentedControl);
}
Test
I want to get all entry controls value on button click.
My code is as below - this is how I am adding dynamic control on page:
public BookSeat()
{
ScrollView scroll = new ScrollView();
StackLayout stack = new StackLayout();
int count = Convert.ToInt32(Application.Current.Properties["NoPersonEntry"]);
for (int i = 0; i < count; i++)
{
stack.Children.Add(
new StackLayout()
{
Children = {
new Label (){TextColor = Color.Blue, Text = "First Name: ", WidthRequest = 100,StyleId="FnameLabel"+i },
new Entry() {StyleId="FnameEntry"+i }
}
}
);
}
Button button = new Button
{
Text = "Save"
};
button.Clicked += OnButtonClicked;
stack.Children.Add(button);
scroll.Content = stack;
this.Content = scroll;
}
And below code is for I want to get value on button click
public void OnButtonClicked(object sender, EventArgs e)
{
// Here I want to get value
}
What you can do is to store your entries in a list so that you can access them later on.
For example :
private List<Entry> _myentries = new List<Entry>();
public BookSeat()
{
ScrollView scroll = new ScrollView();
StackLayout stack = new StackLayout();
int count = Convert.ToInt32(Application.Current.Properties["NoPersonEntry"]);
for (int i = 0; i < count; i++)
{
var entry = new Entry() {StyleId="FnameEntry"+i };
_myentries.Add(entry);
stack.Children.Add(
new StackLayout()
{
Children = {
new Label (){TextColor = Color.Blue, Text = "First Name: ", WidthRequest = 100,StyleId="FnameLabel"+i },
entry
}
}
);
}
[...]
}
Now you can do this :
public void OnButtonClicked(object sender, EventArgs e)
{
foreach(var entry in _myentries)
{
var text = entry.Text;//here we go
}
}
I am using FlowListView To set gallery view in my xamarin forms application, with following code..
public class Page1 : ContentPage
{
public Page1()
{
ObservableCollection<ItemModel> List = new ObservableCollection<ItemModel>();
string[] images = {
"https://farm9.staticflickr.com/8625/15806486058_7005d77438.jpg",
"https://farm5.staticflickr.com/4011/4308181244_5ac3f8239b.jpg",
"https://farm8.staticflickr.com/7423/8729135907_79599de8d8.jpg",
"https://farm3.staticflickr.com/2475/4058009019_ecf305f546.jpg",
"https://farm6.staticflickr.com/5117/14045101350_113edbe20b.jpg",
"https://farm2.staticflickr.com/1227/1116750115_b66dc3830e.jpg",
"https://farm8.staticflickr.com/7351/16355627795_204bf423e9.jpg",
"https://farm1.staticflickr.com/44/117598011_250aa8ffb1.jpg",
"https://farm8.staticflickr.com/7524/15620725287_3357e9db03.jpg",
"https://farm9.staticflickr.com/8351/8299022203_de0cb894b0.jpg",
};
int number = 0;
for (int n = 0; n < 20; n++)
{
for (int i = 0; i < images.Length; i++)
{
number++;
var item = new ItemModel()
{
ImageUrl = images[i],
FileName = string.Format("image_{0}.jpg", number),
};
List.Add(item);
}
}
FlowListView listView = new FlowListView()
{
FlowColumnTemplate = new DataTemplate(typeof(ListCell)),
SeparatorVisibility = SeparatorVisibility.None,
HasUnevenRows = true,
FlowColumnMinWidth = 110,
FlowItemsSource = List,
};
listView.FlowItemTapped += (s, e) =>
{
var item = (ItemModel)e.Item;
if (item != null)
{
App.Current.MainPage.DisplayAlert("Alert", "Tapped {0} =" + item.FileName, "Cancel");
}
};
Content = new StackLayout
{
Children = {
listView
}
};
}
}
public class ItemModel
{
public string ImageUrl { get; set; }
public string FileName { get; set; }
}
public class ListCell : View
{
public ListCell()
{
CachedImage IconImage = new CachedImage
{
HeightRequest = 100,
Aspect = Aspect.Fill,
DownsampleHeight = 100,
DownsampleUseDipUnits = false,
LoadingPlaceholder = "image_loading.png",
ErrorPlaceholder = "image_error.png"
};
IconImage.SetBinding(CachedImage.SourceProperty, "ImageUrl");
Label NameLabel = new Label
{
Opacity = 0.5,
HorizontalOptions = LayoutOptions.Fill,
HorizontalTextAlignment = TextAlignment.Center,
VerticalOptions = LayoutOptions.End,
};
NameLabel.SetBinding(Label.TextProperty, "FileName");
Grid grd = new Grid
{
Padding = 3,
ColumnDefinitions = {
new ColumnDefinition { Width = new GridLength (1, GridUnitType.Star) },
},
RowDefinitions = {
new RowDefinition { Height=GridLength.Star},
},
};
grd.Children.Add(IconImage,0,0);
grd.Children.Add(NameLabel, 0, 1);
}
}
i added all the dependency of FlowListView, FFImage etc,
This above code just showing blank screen, Not displaying any data...
You're ListCell has nothing to show.
Append the existing lines to set the content to the grid in your custom ViewCell.
grd.Children.Add(IconImage,0,0);
grd.Children.Add(NameLabel, 0, 1);
Content = grd; <--- add this line
Also have you done the following as per advice from the author? i.e. You've added the nuget library to the platforms in addition to the PCL and added the corresponding initialisation code for the library?
You must add this line to your platform specific project (AppDelegate.cs, MainActivity.cs, etc) before you use FFImageLoading:
CachedImageRenderer.Init();
This is what I got in my IOS:
[Register("AppDelegate")]
public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
{
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
global::Xamarin.Forms.Forms.Init();
FFImageLoading.Forms.Touch.CachedImageRenderer.Init(); <---- this line
LoadApplication(new App());
return base.FinishedLaunching(app, options);
}
}
I am creating an application in Xamarin.I want to use Auto-Scroll feature and i am not able to do that in a proper way. I am able to scroll manually. BUt i want to display the next picture automatically without scrolling.
Kindly share your views and codes.
I have used sliders for now. But i would like to know if i can do something better.
Grid SliderGrid = new Grid ();
//SliderGrid.BackgroundColor = Color.Black;
//SliderGrid.Padding = 10;
int SlidercolumnCount = Slider.Count;
RowDefinition Sliderrow = new RowDefinition ();
SliderGrid.RowDefinitions.Add (Sliderrow);
for (int j = 0; j < SlidercolumnCount; j++) {
ColumnDefinition col = new ColumnDefinition ();
SliderGrid.ColumnDefinitions.Add (col);
}
for (int i = 0; i < SlidercolumnCount; i++) {
var vetImageCol = new Image {
HeightRequest=260,
WidthRequest=360,
BindingContext = Slider [i],
Source = Slider [i].CategoryImage,
Aspect=Aspect.AspectFill,
};
Grid.SetColumn (vetImageCol, i);
SliderGrid.Children.Add (vetImageCol);
}
var SliderContent = new ScrollView {
Orientation=ScrollOrientation.Horizontal,
HorizontalOptions=LayoutOptions.FillAndExpand,
//HeightRequest=265,
Content= SliderGrid,
};
It's ok to do it with Task commands like this one:
private async void DoSomethingAsync()
{
await Task.Delay(1000);
DoSomething();
await Task.Delay(1000);
DoSomethingelse();
}
Although it's better to do it with Task return value instead of void but you get the idea
//page view is may ui scroll view
//counter for if my image focus on last image then return on 1 img
//new PointF((float)(your image size * count),your top margin or your fram y);
int count = 0;
public async void StartTimer()
{
await Task.Delay(3000); //3 sec
count += 1;
if (count == 5)
{
count = 0;
}
var bottomOffset = new PointF((float)(UIScreen.MainScreen.Bounds.Width * count),0);
pageview.SetContentOffset(bottomOffset, animated: true);
StartTimer();
}
public override void ViewDidLoad(){
StartTimer();
}