appcelerator titanium create ScrollView with pagination control - titanium

I need create a ScrollableView with two simultaneous views.
looking at the image is better understood
desired prototype
I tried to synchronize 2 ScrollableView, to make a continuous ScrollableView false and get the effect. But I could not synchronize the movements of the ScrollableView
2 ScrollableView

If you don't need the "continuous slide" (quickly slide through all views) then I would use the ScrollView and implement the stop part in the scrollend event. Check if a multiple of your view width is half the width in or not and then move to the beginning or end of the view. Its a bit hard to describe :)
If you just need it for iOS you can use clipView:
http://docs.appcelerator.com/platform/latest/#!/api/Titanium.UI.ScrollableView-property-clipViews
to show the previous/next view.

Related

Is there a way to synchronize the scroll of two different scroll views which are on the same page?

I have two scroll views in my app. First one contains header of a list which works horizontally and the second contains the list which works horizontally and vertically ( in both directions). So now I want to synchronize the scroll of both scroll views. I want both scroll views work simultaneously.
You would need to look into the Scroll event and the Scroll To delegate action of a ScrollView
Scrolled event documentation can be found here
ScrollToAsync documentation can be found here
Depending on exactly what you're trying to achieve you could assign the the ScrollView.Scrolled event of each ScrollView:
ScrollView.Scrolled += ()=>{
// If vertical get Scroll Y and translate it to your second ScrollViews Scroll X
SecondScrollView.ScrollToAsync(ScrollView.ScrollX, SecondScrollView.ScrollY, true)
}
SecondScrollView.Scrolled += ()=>{
// If vertical get Scroll X and translate it to your first ScrollViews Scroll Y
ScrollView.ScrollToAsync(SecondScrollView.ScrollX, ScrollView.ScrollY, true)
}
I haven't had chance to test the above, it's more of a quick example to get you going in the right direction, a few things you'd have to look out for behavior wise is when ScrollToAsync is called it will likely fire off the scroll event of that ScrollView So you'll want to handle that to ensure there isn't some weird recursive behaviour.

How to replace a view

Application requires more than one window (Lets call A,B,C). Each window has more than one view (table views, image views as well as web view). Lets say window A has three views (x, y,z) and window B has three views (d,e,f). Application needs to display images of different size on orientation change.
I have achieved the same using gesture event listener and looping through windows for views and replacing the view with new images. The problem I have is when we navigate from one window to other and the orientation changes, the loading of view after looping goes for a toss. Is there a better way to achieve the same ?
Is there a method in titanium like following code to replace a view ?
var self=Ti.UI.currentWindow
var newView=Ti.UI.createImageView({image:'abc.png'})
self.replace(self.children[1],newView )
Unfortunately there is now replace method.
You need to remove the whole view and add it again but this can cause a wrong layout if you have more than one view on a same level. The implementation then depends on the layout which was set (vertical, horizontal, composite etc).
For example in vertical layout removing an item and simply add a new one would remove your specified item but appends the new one at the end since you can't specify in which order it should be added.
If you have a composite layout you can specify absolute positions but adding a new view causes a higher zIndex for this view so that it will hide views that were previously added at the same/similar position.
Why not simply change the image link ?
var self = Ti.UI.currentWindow;
self.children[1].image = 'bcd.png';
Well you could always lock the orientation of your window. But this isnt exactly good practice (especially for iOS).
Generally orientation changes are handled pretty well if you define the width and height of your views to be percentages or Ti.UI.FILL, if you have a composite layout. Check that you are not giving the views absolute coordinates as this could cause layout problems. If you have a vertical or horizontal layout you usually don't have to worry about orientation change, unless you did not nest your views in a main container correctly.
Prasad,
If this is about just ensuring that the images look good on different orientations,you can make use of the different folders provided by Titanium in the android/images folder.You can just make different images for each of the orientations and device sizes.For IOS you can change just the images on orientation change as you are already doing.
https://wiki.appcelerator.org/display/guides/Using+density-specific+resources+on+Android
If you are concernced about the layout there are couple of things you can do:
1.Give all the height or width values in percentages.This way all elements will be re sized once the orientation changes automatically.
2.On each window open check if the orientation is vertical or horizontal by default and accordingly set the image attribute of the imageView.
Ti.UI.orientation
This property will give you the orientation of the window by default.Values of this property could be this
Ti.UI.PORTRAIT
Ti.UI.UPSIDE_PORTRAIT
Ti.UI.LANDSCAPE_LEFT
Ti.UI.LANDSCAPE_RIGHT
Use "if else" and accordingly set the images.

When using UIScrollView, how do I make the viewed ends to be complete, not partial

How do I make the UIScroll view show complete views, not partial views?
(Note) I don't want it jumping to a complete view. It needs to move naturally or at least not immediate... needs to be smooth.
thanks
If your views are all of a constant size and you just want left/right or up/down scrolling, set pagingEnabled on the scroll view to YES. Supposing you wanted your scroll view to be 320x480 but to show the sides of the next and previous pages (so, e.g., each thing inside the view was 280 points wide), you'd size the scroll view to be 280x480 but set masksToBounds to NO.
If you have a more complicated scheme, install a scroll view delegate and act on scrollViewDidScroll:, paying attention to contentOffset. Probably you want to implement logic like:
add an observer on tracking; when it transitions to NO from 'YES' enable your logic inside scrollViewDidScroll: In there:
if a forced scroll is pending, cancel it
calculate where you'd force the scrolling to from the current position
schedule a scroll to there (which you'll effect via setContentOffset:animated:) for half a second from now
You can use a non-repeating NSTimer for the scheduling aspect. The logic you've essentially implemented is that if the user stops adjusting the view, wait for the natural inertia to end (which you'll detect by the 0.5 second gap since last movement), then transition smoothly to the nearest aligned position.
Check out Apple's documentation here first:
https://developer.apple.com/library/ios/#documentation/WindowsViews/Conceptual/UIScrollView_pg/Introduction/Introduction.html
Then the ScrollViewSuite sample:
https://developer.apple.com/library/ios/#samplecode/ScrollViewSuite/Introduction/Intro.html#//apple_ref/doc/uid/DTS40008904
I think you are referring to Paging techniques.

How to create an "Add to reading list" animation effect

I'm trying to make an animation effect similar to the one on Safari(iPhone) when you add an element to the reading list. It's similar to the one that appears when starting to download an item from App Store application: the application item drops to the dock to start downloading.
First it bounces up and then goes to the dock. It's a very nice effect that Apple uses on their OS.
I have an image view on screen that I want to drop with this kind of animation to my toolbar in my application.
If there is someone who did it or know what's the name of the effect, could please tell me how to do it.
Thank you.
"Add to reading list" shows no animation on my phone but of your description it sounds like the "Open in background"-animation in Safari (iPhone). My answer describes that animation.
I wrote a thing like that a few months ago and much of it is doable while some of it is not. Your questions showed me that more people are to know how it is done so I wrote a blog post about it. I will describe the high level approach and challenges here but you can read more about it in that post.
Getting to content to animate
If you choose to animate the view that is on screen down to the (in your case) tool bar then you will only have to access its layer. If you want the original view to remain and animate a visual copy (like the "open in background"-Safari animation) down to the bar item then you should create a new layer and draw the content of your layer into an image and set that image as the content of the layer that you are animating
Calculating the end position
The start position of the animation is simply the frame of the view. The end position is very tricky since bar items (both tool bar items and tab bar items) are not UIView subclasses and doesn't have a public view property. This causes problems when you want to shake the bar item later on.
I decided to make a visual approximation of the end position using some simple heuristics. If you know before hand that you will only animate to a single bar item then the end position can be hard coded to a suitable frame.
Animating along a path
There is nothing special to moving, scaling and rotating the layer from the start to the end position. If you want to read more about how I did it you can look at the post I wrote.
Shaking the bar item
This cannot be done without a lot of custom code or using private API at the moment. Since bar items doesn't have a view or a layer there is no accessible layer for you to animate. I guess that you could have a custom animating image that does the shake and set that during the animation and set the new image afterwards. The approach of drawing into an image and animating that doesn't work that well either since there is no accessible layer who can draw its content into the image (you want this for the special effect of the tool bar item and tab bar item).
...put all this together and tweak it to your special needs and you will have an animation that resembles the animation you are looking for.

Graying out an NSWindow's content

I have an NSWindow with 2 NSViews (an NSSplitView and a custom NSView). Accessing the data to populate these views can take some time. During this period, I'd like to gray out the content of these views.
My first approach was to have a black third NSView that covered the other 2 and achieve the graying out effect by changing its alpha value. However I've since learned having a hierarchy with sibling views is undefined.
What is the best approach here?
Cache the NSBitmapImageRep of the 2 views, then replace them with the 3rd view, using the cached image(s) as background
Set the alpha value for each view separately (still not quite sure how to get the black background for the graying effect)
Something I haven't considered
I'd use a child window. Set its content view to a plain black view (hopefully with status and progress information in subviews), and its alpha value to the desired fade-out, and add it as a child window of the window whose content you want to fade out.
I'd teach the views how to draw themselves in a disabled state, but there are other suggestions here:
How can I darken everything displayed in a single NSView?