i've started WP7 development about a week ago (and programming in general) and I've been working on a little app, but i faced a problem with getting ScrollViewer to function properly.
Application creates a new pivot item when certain conditions are met, and i'm trying to add a scrollable textblock in it, which shows randomly chosen strings of text from a list every time user taps the screen, from which some are long enough to require vertical scrolling.
// A bit cleaned version of my code,
// had to translate stuff a bit for them to make sense
// Sets the PivotItem header depending on user choice
// and creates ScrollViewer and TextBlock
PivotItem newPivotItem = new PivotItem { Header = choice, Name = "newPivot"};
ScrollViewer newScrollviewer = new ScrollViewer();
TextBlock newTextBlock = new TextBlock { Text = "tap the screen", Name = choice};
newScrollviewer.Content = newTextBlock;
newPivotItem.Content = newScrollviewer;
mainPivot.Items.Add(newPivotItem);
Text is added in Tap event, which just replaces the Text property with new string. Text updates just fine and as intended, but ScrollViever stops working after update.
newString = list[rand];
PivotItem selectedPivot = mainPivot.SelectedItem as PivotItem;
TextBlock selectedText = selectedPivot.FindName(choice) as TextBlock;
selectedText.Text = newString;
selectedText.Height = selectedText.ActualHeight;
Similiar ScrollViewer - TextBlock combination in another PivotItem which is declared in xaml works just fine.
I found what actually broke the ScrollViewer, it was transition animation which i had set to trigger on text update. I had a little typing error on it and somehow while the transition worked, scrollviewer didn't.
Related
as the Toolbar or Titlearea on scroll animation feature is referenced in the last section of the Toolbar API, and also in this great video tutorial (starting at about min 45), the animation works well under given circumstances.
I was not able to find any documentation about what these have to be, however I found one circumstance, in which it does not work. Here is a working example to demonstrate the problem:
Form hi = new Form("Title", new BoxLayout(BoxLayout.Y_AXIS));
EncodedImage placeholder = EncodedImage
.createFromImage(Image.createImage(hi.getWidth(), hi.getWidth() / 5, 0xffff0000), true);
URLImage background = URLImage.createToStorage(placeholder, "400px-AGameOfThrones.jpg",
"http://awoiaf.westeros.org/images/thumb/9/93/AGameOfThrones.jpg/400px-AGameOfThrones.jpg");
background.fetch();
Style stitle = hi.getToolbar().getTitleComponent().getUnselectedStyle();
stitle.setBgImage(background);
stitle.setBackgroundType(Style.BACKGROUND_IMAGE_SCALED_FILL);
stitle.setPaddingUnit(Style.UNIT_TYPE_DIPS, Style.UNIT_TYPE_DIPS, Style.UNIT_TYPE_DIPS, Style.UNIT_TYPE_DIPS);
stitle.setPaddingTop(15);
// hi.setLayout(new BorderLayout()); // uncomment this for the animation to break
Container contentContainer = new Container(BoxLayout.y());
contentContainer.setScrollableY(true);
// add some elements so we have something to scroll
for (int i = 0; i < 50; i++)
contentContainer.add(new Label("Entry " + i));
hi.add(contentContainer);
// hi.add(BorderLayout.CENTER, contentContainer); // use this line instead of the above for the animation to break
ComponentAnimation anim = hi.getToolbar().getTitleComponent().createStyleAnimation("Title", 200);
hi.getAnimationManager().onTitleScrollAnimation(anim);
hi.show();
With my current app and the codesample from the Toolbar API (which is roughly adapted here), I found out that the onScrollAnimation event is not being called, when a scroll occurs inside a BorderLayout. Even when I have a separate container, which is not the contentpane itself, and I set setScrollableY(true); to true, the animation works properly. The animation stops working, when this very container is put into Center of the Form, via Borderlayout. in the example above, the layout is exactly the same, as there are no other components in other areas of course, but it breaks the animation.
How to solve this? In my app, I have the need for a BorderLayout but still want to use this cool feature. Also, this is a very un-intuitive feature, if it works for some, but not all layouts. It should be completely layout-agnostic and work in every case.
Thank you.
The adapter is bound to the forms content pane scrolling so it won't work if you have a border layout in here. In that case scrolling isn't detected because the code just isn't aware of the scrolling. It would need to track the scrolling of any component in the UI to detect that scrolling.
as hinted by Shai, the solution is the following:
hi.setLayout(new BorderLayout());
Container contentContainer = new Container(BoxLayout.y());
contentContainer.setScrollableY(true);
// add some elements so we have something to scroll
for (int i = 0; i < 50; i++)
contentContainer.add(new Label("Entry " + i));
hi.add(BorderLayout.CENTER, contentContainer); // use this line instead of the above for the animation to break
ComponentAnimation anim = hi.getToolbar().getTitleComponent().createStyleAnimation("Title", 200);
hi.getAnimationManager().onTitleScrollAnimation(contentContainer, anim);
instead of using the onTitleScollAnimation to just add the animation, provide your own scrollable "body" or content container as the first argument, appended by the animation(s).
I need a MenuBar on the left side of my screen that can slide in and out. As this app is crossplattform it should be on the left side and not like the usual ApplicationBar on the Bottom or NavigationBar on Top.
What I have so far is:
private bool isTapped = false;
private void TEST_TAP(object sender, TappedRoutedEventArgs e)
{
System.Diagnostics.Debug.WriteLine("TAP");
Storyboard s = new Storyboard();
DoubleAnimation doubleAni = new DoubleAnimation();
doubleAni.To = -30;
if (isTapped) doubleAni.To = 0;
doubleAni.Duration = new Duration(TimeSpan.FromMilliseconds(500));
Storyboard.SetTarget(doubleAni, LOGO);
Storyboard.SetTargetProperty(doubleAni, "(UIElement.RenderTransform).(TranslateTransform.XProperty)");
s.Children.Add(doubleAni);
s.Begin();
}
The bar I want to move is a Grid or should be something similar. But this even fails to move a single Image. I googled a bit and replaced "(UIElement.RenderTransform).(TranslateTransform.XProperty)" with "(Canvas.Left)". This doesn't crash but also doesn't move anything else.
Any ideas or solutions?
EDIT:
Well I played around a lot and now I know (and tested it) that "(Canvas.Left)" only works inside of a Canvas. Yay.
My App looks like this: Scrollview (horizontal) and inside is a Grid with columns to display different stuff. The left-most Column contains another Grid that I want to move out of the screen and back in again. But how do I move a grid with Storyboard-animation?
If anybody thinks of a different way to do this, I'm totally happy if it works in any way.
EDIT2:
It seems to be THE way to use Storyboard.SetTargetProperty(doubleAni, "(UIElement.RenderTransform).(CompositeTransform.TranslateX)"); but it keeps crashing =/
Before using this transform you need to add it:
Storyboard s = new Storyboard();
DoubleAnimation doubleAni = new DoubleAnimation();
doubleAni.To = to;
doubleAni.From = from;
doubleAni.Duration = new Duration(TimeSpan.FromMilliseconds(250));
// THIS LINE IS NEW
NaviBar.RenderTransform = new CompositeTransform();
Storyboard.SetTarget(doubleAni, NaviBar);
Storyboard.SetTargetProperty(doubleAni, "(UIElement.RenderTransform).(CompositeTransform.TranslateX)");
s.Children.Add(doubleAni);
s.Begin();
This does the trick. It's still not the functionality that I wanted but the hardest part - the animation - works now.
I am trying to create an animation to make it look like a button turns over and the back shows. So what I was trying to do is:
1- Show a button with BackgroundColor x. (The button now has a Width of null, the property ActualWidth does have a value.)
2- Create a double animation that changes the width of the button to zero.
DoubleAnimation widthAnimation = new DoubleAnimation();
widthAnimation.From = this.ActualWidth;
widthAnimation.To = 0;
widthAnimation.SpeedRatio = 3;
widthAnimation.Duration = TimeSpan.FromMilliseconds(800);
3- Change the BackgroundColor of the button.
ColorAnimation colorAnimation = new ColorAnimation();
colorAnimation.From = State ? _xColor : _yColor;
colorAnimation.To = State ? _yColor : _xColor;
colorAnimation.BeginTime = TimeSpan.FromMilliseconds(400);
colorAnimation.Duration = TimeSpan.Zero;
4- Change the width back to it's original value.
widthAnimation.AutoReverse = true;
The problem is when the animation runs twice the animation reads this.ActualWidth while animating, which causes it to fail to the original width. How can I solve this? I would like to set the Width back to null again, but it seems impossible to me.
You'd better use xaml style and template to "declare" what you want and let WPF/Silverlight take care of all.
If you try to do the same thing by code you can do it but you need to know what the framework does behind the scenes.
Basically you can set
- Style to define the values of some properties of the control
- DataTemplate to define the visual representation of the control's content
- ControlTemplate to define the appearance of the control
Each of those can have Triggers
- Property Triggers
to set properties or starts actions, such as an animation
when a property value changes or when an event is raised;
EventTriggers and Storyboards
to start a set of actions based on the occurrence of an event
If you like to learn about XAML Style and Template,
take a look at http://msdn.microsoft.com/en-us/library/ms745683.aspx
Spend a day to learn and save many hours (or days) of try and error and frustration!
To go right to the point, in your case I think you should use a Storyboard.
See http://msdn.microsoft.com/en-us/library/ms742868.aspx
where you can find also the code equivalent of XAML examples
I came to the idea to targetting the MaxWidth instead of the actual Width. I now use a KeyFrameCollection which sets the MaxWidth to int.MaxValue at the start (so also at the end when using autoreverse).
It will work fine untill there will be phones with a resolution bigger than the max int value.
The code:
DoubleAnimationUsingKeyFrames widthAnimation = new DoubleAnimationUsingKeyFrames();
widthAnimation.KeyFrames.Add(new DiscreteDoubleKeyFrame()
{
KeyTime = TimeSpan.Zero,
Value = int.MaxValue,
});
widthAnimation.KeyFrames.Add(new LinearDoubleKeyFrame()
{
KeyTime = TimeSpan.FromMilliseconds(1),
Value = ActualWidth,
});
widthAnimation.KeyFrames.Add(new LinearDoubleKeyFrame()
{
KeyTime = TimeSpan.FromMilliseconds(400),
Value = 0,
});
widthAnimation.Duration = TimeSpan.FromMilliseconds(400);
widthAnimation.AutoReverse = true;
I'm now facing the most common problem faced my many while working with listboxes. Though I found many answers the the forum, nothing seems to work for me or else i have got it wrong. .
I have created a listbox through code. Every listbox item has a stackpanel and within it two textblocks. the stackpanel has vertical orientation.The foreground of the textblocks have been set to specific colors. When an item has been selected or clicked it moves to another page and on the close of the new page it returns to the old page.
My problem is that, when a listbox item has been clicked, it does not show the selection color which is by default the phones accent color before moving to the next page. Is it because the color of the textblocks have already set while creating the listbox?
So i tried to set it the foreground of the selected item through the SelectionChanged() like this
ListBoxItem selItem = (ListBoxItem)(listboxNotes.ItemContainerGenerator.ContainerFromIndex(listboxNotes.SelectedIndex));
selItem .Foreground = (SolidColorBrush)Application.Current.Resources["PhoneAccentBrush"];
But this does not work, and i assume its cuz there is a stackpanel inside the item.
How exactly this needs to be done? Do i need to retrieve the textblocks inside the stackpanel and set the foreground?? I have not used binding here. Visual Tree Helper???
Thanks
Alfah
In general, the selected color doesn't change on lists where you're navigating.
From my experience with android, there's no 'selector' background on WP7. If you're looking for a cool UI effect that shows some action is happening, the TiltEffect is definitely recommended, and very easy to implement.
http://www.windowsphonegeek.com/articles/Silverlight-for-WP7-Toolkit-TiltEffect-in-depth
However - if you're creating an app that doesn't have immediate navigation, it is possible that you might want a 'selected' cell color / etc. I've attached an image:
https://skydrive.live.com/redir.aspx?cid=ef08824b672fb5d8&resid=EF08824B672FB5D8!366&parid=EF08824B672FB5D8!343
If you note here, the buttons are related to the selected item on the list - I.e. the user can perform 4 different actions based on the selected item, (but they must select an item first!).
internal void SelectionChanged()
{
var item = (((ListBoxItem) _view.servers.SelectedItem).Content) as StackPanel;
if (item != null)
{
for (int i = 0; i < _view.servers.Items.Count; i++)
{
var val = (((ListBoxItem) _view.servers.Items[i]).Content) as StackPanel;
var tb = val.Children[0] as TextBlock;
var tb2 = val.Children[1] as TextBlock;
if (i == _view.servers.SelectedIndex)
{
tb.Foreground = tb2.Foreground = (SolidColorBrush) App.Current.Resources["PhoneAccentBrush"];
}
else
{
tb.Foreground = tb2.Foreground = (SolidColorBrush) //regular color here, b/c all these should no longer be selected
}
}
}
}
The ListItemContainer will have it's Foreground changed automatically. To inherit this, simply don't specify a colour (or style) on your TextBlock.
I have a windows application with DataGridView as data presentation. Every 2 minutes, the grid will be refreshed with new data. In order to keep the scroll bar in sync with the new data added, I have to reset its ScrollBars:
dbv.Rows.Clear(); // clear rows
SCrollBars sc = dbv.ScrollBars;
dbv.ScrollBars = ScrollBars.None;
// continue to populate rows such as dbv.Rows.Add(obj);
dbv.ScrollBars = sc; // restore the scroll bar setting back
With above codes, the scroll bar reappears fine after data refresh. The problem is that the application requires to set certain cell as selected after the refresh:
dbv.CurrentCell = dbv[0, selectedRowIndex];
With above code, the cell is selected; however, the scroll bar's position does not reflect the position of the selected cell's row position. When I try to move the scroll bar after the refresh, the grid will jump to the first row.
It seems that the scroll bar position is set back to 0 after the reset. The code to set grid's CurrentCell does not cause the scroll bar to reposition to the correct place. There is no property or method to get or set scroll bar's value in DataGriadView, as far as I know.
I also tried to set the selected row to the top:
dbv.CurrentCell = dbv[0, selectedRowIndex];
dbv.FirstDisplayedScrollingRowIndex = selectedRowIndex;
The row will be set to the top, but the scroll bar's position is still out of sync. Not sure if there is any way to make scroll bar's position in sync with the selected row which is set in code?
I found an answer to resolve issue. As I mentioned that the control does not have methods or properties to set the correct scroll bar value. However, the scroll bar and the DatagridView content will display correct if there is an interaction directly towards to the UI such as touch the scroll bar or grid cell. It looks like that the control needs to be refocused and a repaint.
Simply use the following codes does not cause the scroll bar reset:
dgv.Select();
// or dbv.Focuse();
The way I found is that I have to make the DatagridView control disappear to back again. Fortunately, I have a tab control with several tabs. Then I switch the tab to get scroll bar reset:
int index = myTabCtrl.SelectedIndex;
if (index == (myTabCtrl.TabCount)) {
dgv.SeletecedIndex = 0;
}
else {
dgv.SelectedIndex = index + 1;
}
myTabCtrl.SelectedIndex = index;
If you don't have any way to hide the DatagridView on your form, you could simply minimize the form and then restore it back.
The problem is that there will be a fresh on the UI.
It seems, TAB, SHIFT+TAB, END keys don't always bring last column into the visible view.
The following code inside the CurrentCellChanged event handler seems to fix this issue (vb.net):
If Me.MyDataGridView.CurrentCell IsNot Nothing Then
Dim currentColumnIndex As Integer = e.MyDataGridView.CurrentCell.ColumnIndex
Dim entireRect As Rectangle = _
Me.MyDataGridView.GetColumnDisplayRectangle(currentColumnIndex, False)
Dim visiblePart As Rectangle = _
Me.MyDataGridView.GetColumnDisplayRectangle(currentColumnIndex, True)
If (visiblePart.Width < entireRect.Width) Or (entireRect.Width = 0) Then
Me.MyDataGridView.FirstDisplayedCell = Me.MyDataGridView.CurrentCell
'OR Me.MyDataGridView.FirstDisplayedScrollingColumnIndex = currentColumnIndex
End If
End If