Can I implement something similar to iOS "Folders"? - iphone

I am going to make something that very visually similar to iOS4 folders but it's not folders at all )))
For example, I have 4 labels on screen - see sketch. Screen splits, if user click on label. Other lebels going down and we can see some text between splited views. If user click once more - view back to "normal" state as before. And so on.
Questions are:
is it confront iPhone HIG and app can be rejected?
what is the easiest way to implement this?
thanks )
alt text http://a.imageshack.us/img196/1306/sketch1.gif

Your App can always be rejected, for no reason at all.
This seems less like folders and more like an outline with collapsable items (or code folding in a programming editor). Plenty of outliner like apps in the store so no reason you should be able to do this (but read the first line of this answer again! No promises!).
Lots of ways to implement this. Here's a random quick one: If you use a UITableView and then have a UITableViewDataSource implementing class that has items marked as hidden/vislble. Then your numberOfRowsInSection method could return only the number of visible rows and the tableView:cellForRowAtIndexPath: would have to skip hidden rows (this might be too slow if you have many items - if so, cache visible count, use secondary array of indexes (or NSMutableIndexSet) of visible items, etc).

Related

How to rebuild the email-app (specificly the mail-overview)?

I want to reabuild the email-app one to one for a private-message system.
I am working at the moment on the email-overview-screen.
Now I have a ViewController for this with a UITableView and a UINavigationBar on it.
2 simple questions:
How do I get more then one line in the cell, specificly 2-4
different font-types (bold / not bold / blue) exactly rebuilded as
seen in the link above?
How do I can add a PullDown-Refresh functionality? (You know, this
pull down, oh refrash, thing, emails have)
Use a custom cell, you can put in whatever information and links and styles as you want. You can even use UIWebViews as the cells, which could make styling and links easier.
Many examples of this have a look at the answers to this SO question.

How can I change a ViewController list (by changing predicate) without popping and pushing?

I have a ViewController whose view results from data from a fetch request with Predicate 1. I'd like to repeat the fetch request with a more restrictive Predicate 2 that will give a SUBSET of the data using Predicate 1.
Then I'd like to update (and possibly animate) that view on the iPhone screen by pressing a toggle button, so that the old and new views expand and collapse the rows. (I don't want to do this modally, as I'd like the user to see which rows came from the old rows.)
I'm thinking of something like the Phone application on the iPhone. Under the "Recents" tab, you'll see "All" and "Missed" buttons. When you press these buttons, it switches between showing all calls and just the missed ones by expanding/collapsing the rows. As far as I can tell, this is not a modal transition.
Can someone give me pointers as to how to do this?
If your view is a UITableView, you can use a combination of
-deleteRowsAtIndexPaths:withRowAnimation:
and
-deleteSections:withRowAnimation:
as well as the corresponding -insert methods, if applicable. You can batch multiple changes (so they animate at the same time) with -beginUpdates and -endUpdates.
I'm not aware of any way you'll be able to do this that doesn't involve iterating over one of the two sets and repeatedly calling -indexForObject on the other, though.
I found a way to expand/collapse rows by changing the heights of each cell, using tableView:heightForRowsAtIndexPath:indexPath:, as in:
http://www.alexandre-gomes.com/?p=482
Hope that's helpful to someone!

Rendering a Long Document on iPad

I'm implementing a document viewer with highlighting/annotation capabilities for a custom document format on iPad. The documents are kind of long (100 to 200 pages, if printed on paper) and I've had a hard time finding the right approach. Here are the requirments:
1) Basic rich-text styling: control of left/right margins. Control of font name, size, foreground/background color, and line spacing. Bold, italics, underline, etc.
2) Selection and highlighting of arbitrary text regions (not limited to paragraph boundaries, like in Safari/UIWebView).
3) Customization of the Cut/Copy/Paste popup (UIMenuController) This is one of the essential requirements of the app.
My first implementation was based on UIWebView. I just rendered the document as HTML with CSS for text styling. But I couldn't get the kind of text selection behavior I wanted (across paragraph boundaries) and the UIMenuController can't be customized from within UIWebView.
So I started working on a javascript approach, faking the device text-selection behavior using JQuery to trap touch events and dynamically modifying the DOM to change the background color of selected regions of text. I built a fake UIMenuController control as a hidden DIV, positioning it and unhiding it whenever there was an active selection region.
Not too shabby.
The main problem is that it's SLOOOOOOOW. Scrolling through the document is nice and quick, but dynamically changing the DOM is not very snappy. Plus, I couldn't figure out how to recreate the magnifier loupe, so my fake text-selection GUI doesn't look quite the same as the native implementation. Also, I haven't yet implemented the communication bridge between the javascript layer and the objective-c layer (where the rest of the app lives), but it was shaping up to be a huge hassle.
So I've been looking at CoreText, but there are precious few examples on the web. I spent a little time with this simple little demo:
http://github.com/jonasschnelli/I7CoreTextExample/
It shows how to use CoreText to draw an NSAttributedText string into a UIView. But it has its own problems: It doesn't implement text-selection behavior, and it doesn't present a UIMenuController, so I don't have any idea how to make that happen. And, more importantly, it tries to draw the entire document all at once, with significant performance degradations for long documents. My documents can have thousands of paragraphs, and less than 1% of the document is ever on screen at a time.
On the plus side, these documents already contain precise formatting information. I know the exact page-position of every line of text, so I don't need a layout engine.
Does anyone know how to implement this sort of view using CoreText? I understand that a full-fledged implementation is overkill for a question like this, but I'm looking for a good CoreText example with a few basic requirements:
1) Precise layout & formatting control (using the formatting metrics and text styles I've already calculated).
2) Arbitrary selection of text.
3) Customization of the UIMenuController.
4) Efficient recycling of resources for off-screen objects.
I'd be happy to implement my own recycling when text elements scroll off-screen, but wouldn't that require re-implementing UIScrollView?
I'm brand-new to iPhone development, and still getting used to Objective-C, but I've been working in other languages (Java, C#, flex/actionscript, etc) for more than ten years, so I feel confident in my ability to get the work done, if only I had a better feel for the iPhone SDK and the common coding patterns for stuff like this. Is it just me, or does the SDK documentation really suck?
Anyhow, thanks for your help!
Does your document have any semantic components other than each paragraph? If you already have some concept of sections or pages, I would recommend you render each one of those as an independent tablecell. It's pretty simple to create a tablecell that makes you forget you're actually looking at a UITableView. All you would need to do is override drawRect: and setSelected: and setHighlighted: and tah dah! No More cell dividers unless you want them. Furthermore you could do some nifty things by using a tableview as your base. If you defined sections in the UITableView then you could have a nifty header that scrolls along as you're paging through your document. Another thing you could do is add a "jump to section" bar / a bookmarks menu, and that way you don't have to provide selection across the boundaries of sections.
Massive copy paste blocks would be pretty painful on the system as well. Further, if you went through the trouble to provide this content you might not want to make it too easy for someone to copy it all at once... (Can't follow this line of thought more without more specifics on your project).
If you really do want to provide the copy paste options you could add buttons to each logical page or section that immediately selects and copies the whole section for the user's convenience. (Maybe with citation associated?)
I recommend you lookup the UITableViewCell UITableViewDelegate and UITableViewDataSource in the SDK docs as those pages will significantly help if you choose to use this suggestion.
Just two random observations:
Can you afford to create a paging interface? (As opposed to “endless scrolling”.) It looks like a paging interface would be a lot easier on system resources.
The UIActionBar is actually the UIMenuController class. The interface is a bit weird, as the menu is a singleton (wtf?), but I’m sure you’ll have no trouble figuring it out.
Hope that helps.
Here's a potential solution, but I don't know if it's crazy. Since I'm still so new to iPhone development, this might be a big no-no.
Anyhow, I had the idea to render each paragraph of the document (whose dimensions I've already precisely calculated) as a cell in a UITableView. Since UITableView already has mechanisms for cell recycling, I wouldn't have to implement that from scratch, and the document could be arbitrarily long without causing resource consumption problems.
Of course, I'd want to get rid of the line separators between cells, since I want the UI to look like a document instead of a table.
Or maybe I could render each page of the document (like a typical PDF, this is a paged-document format) as a table cell, and override the cell-separator graphic to look like a page boundary...
But would it be possible to get rid of the default touch behavior within the table, and instead implement text-selection on the table cell contents? Would it be completely impossible to implement text selection that crosses paragraph boundaries (between multiple table cells)?
The UIWebView is a good choise, but we need another application to pre render the pages percisely using each font and each style sheet and store the rendring information into a database table:
chapter_id int primary key,
startlocation int,
end location int,
fontsize int (or stylesheetname string)
Using JavaScript we can calculate how many words fit in a div with out scrolling.
UIWebView is good as it provide rich content and it has selection and highlighting behavior.
Hope this helps.

Creating an alternative way to scroll TableView on iPhone

I currently have a TableView with over 35,000 cells. Obviously the standard iPhone flick-and-scroll becomes inefficient with this many cells. I have already implemented search but still think that a way to scroll the entire table is necessary. I am currently using the
-sectionIndexTitlesForTableView:
method to populate the side with the relevant characters, and I want similar functionality to that in Apple's Remote app. I do not have section titles in my table and simply want the sectionIndex to be an alternative way to scroll through the entire 35,000 cell table. How should I go about doing this?
My instinct tells me that a list that large could probably be broken down into smaller sections that could be filtered using the standard hierarchical navigation on the iPhone - that said, without knowing what exactly the data is I can't say that with any confidence.
You say you don't have any section titles - is the list alphanumeric? If so, what is wrong with having a standard alphabetical sectionIndex and sectionTitles?

How do I create a dictionary-style scroll bar for iPhone (like in the Contacts list)?

I am creating an iPhone app which I would like to have a similar interface to the iPhone's native contact picker view, i.e. an alphabetical list which you can scroll through, with a search bar up top which narrows down the list. Particularly, I'd like to be able to show the letters of the alphabet down the side so that as you scroll through the list, you see your position in the alphabet in the scrollbar. The problem is that my data basically consists of key-value pairs, not contact data, so I can't easily use the native contact picker.
As far as I can see, I have two options to achieve what I want:
Use the ABPeoplePickerNavigationController class and hack it to use an address book which I fill myself with non-address type data. The problem with this is that, by default, the address book will fill up with the contacts from the iPhone so that each time the app opened, I'd have to flush those contacts and build my own list. (Not to mention other problems associated with using an interface which is bound to a particular data structure)
Use a UISearchBar and UIScrollView. This would be fine, but I'm not sure how to do anything to the scroll bar except change its colour - I can't see how to override its contents.
Any advice on which is the simplest way? What are the pitfalls (particularly of 1)?
To get the letters down the side, you can just provide a -sectionIndexTitlesForTableView: method in your table view datasource. As for searching, there's a bit more work there, and it's very dependent on your data. A UISearchBar is the place to start, however.
For a search bar, have a look at TTSearchBar in the Three20 library.
Everything else can be easily implemented using UITableView.