I'm looking for a way to create kind-of an article reader which would have 2-3 columns of text which could occasionally wrap about some image. Just like it's done in "New York Times" or "Wall Street Journal" and other iPad applications.
Also, that text should be paged and every page should have UITableView at it's side (just like in "Wall Street Journal" app). But that looks like an easy part.
What would be the best approach to do such thing? Use UIWebView with CSS3 multi-columns (seems easiest, but will it work properly) or there is another obvious way I don't know about (and google doesn't help either)?
Edit:
One more thing, if it is possible use UIWebView with CSS3, then how about calculating required UIWebView width to "columnize" it properly? As I've experienced in the past text height calculations are painful and now we would have to deal with some wrapped images too.
If you’re doing it with CSS, then try -webkit-column-count:n, it might help. Otherwise, since iPad has iOS 3.2 which brings Core Text, that might also help.
However it seems that column-count arranges a block of text so that it is laid out with a certain number of columns, while its height can grow beyond the bounds of the screen (page).
Related
I have several local html files and I want to show them in a table with static(for now) cells.
Each UIWebView would have a different height (I dont want to have any scrolls in the UIWebView) so obviously each cell has a different height. Most of the comments i read discourage the usage of UIWebView in table cells. What do you think : is this applicable ? will it be slow and need time to load?
UIWebview in tableview cells will affect the performance for sure. To display Html content in tableview cells you can use NSAttributedString.
I used a UIWebView in an app to display content coming from the web as rows in a table view.
I know that doing that is discouraged, due to the high memory use of UIWebView, but in my case it was not only a matter of displaying rich text: I had to display HTML loaded from the web, so I give that option a try. In short, I tried it and it worked fine.
The app got memory warnings from time to time, but it was also able to recover memory effectively and run unaffected even on an ipod touch (just 256MB of memory). Performance was possibly affected, but due to the fact that the app was doing just that (loading text from the web and displaying it in the table), the app was perfectly responsive.
One important notice: pages were pretty simple, just text, and each table did not contain more than 15 elements. Furthermore, one thing you have to consider is that the UIWebView introduces a small delay in the rendering, so you will have to deal with it and accept it in your app (there is no way to get rid of it that I know of).
In a later project, I used a different approach: using just one UIWebView and creating the table using HTML/js inside of it. Well, it also worked, but I could not see any big improvement as to peak memory usage nor performance (I checked with instruments).
This is just my experience, I am not trying to say that this will work or that is good practice to do. In any case, I hope it helps.
What is the best way to display lots of RichText (HTML formatted)
At the moment I'm working on an app for a forum. As you'd expect the posts on the site have lots of HTML formatting, lists, images bold text, colored text, etc...
Now there are several options I can think of (non of them ideal, please if you think of any other options post them in the comments):
Custom Cells using NSAttributedString+HTML + DTAttributedTextView for each post?
Problems: I used the NSAttributedString+HTML categories in the app elsewhere and it was less then ideal, creating an NSAttributedString seems to be quite expensive (slow) even in small amounts.
For 10+ posts each of which may be the length of an entire article would be awful + although DTAttributedTextView supports the IMG html tag (an most tags) it doesn't support remote loading of images unless you specify their width and height in the img tag. And for a forum where an IMG tag could be a smiley (10*10) or a screenshot (640*960) there's no way to predict that.
(Since writing this NSAttributedString+HTML, which is now renamed DTCoreText, has added full support for <img> tags and improved greatly!)
Custom Cells with a UIWebView in them for each post?
This one I considered for quite a while, however when reading this blog post I realised a problem that would cause, Smooth scrolling. The idea of having a native application for a site is that it is better then using a simple UIWebView to view the sites mobile theme. If the app lags and is jerky while scrolling that is worse not better (also as I need to display images hiding the webview's like he suggests wouldn't work). Also UIWebView's need to be created on the main thread or they break.
Back to the UIWebView?
Annoyingly besides doing a pathetic cheat, (like in the iFans app) where you only display text and then if they click it a UIWebView loads with all the nice images etc..., the only option left seems to be to do what I think the TapaTalk app does and have the entire thread view as a UIWebView. This isn't too bad as it will probably have quite good performance and will allow me to possibly add user controlled themes etc.. but I find the idea of using a UIWebView in a websites native app repulsive.
Does anyone have any experience creating web powered app, like maybe a facebook client, forum app, or new site app which had to display content from the site (I don't really count a twitter client as it only has to deal with text & links in small amounts per post). Or any ideas on the best way to display RichText content in an iOS app?
Any idea's would have to deal with the lot:
Multi Coloured Text.
Right, Left & Center aligned text.
Images (of variable size).
Bold text.
Text of different sizes & fonts.
Underlines text.
YouTube Videos.
HTML tables.
Just in case the actual question wasn't very clear in all of that I'll sum it up:
"What is the best way to display lots of RichText (HTML formatted) content for a forum client app"
So if I am reading this right, you want the forum posts of a given topic to be cells of a UITableView and the cells need rich formatting?
Assuming this is correct, I imagine each post will take up a lot of the screen (large cell height). In this case, having a UIWebView as a subview might not be as bad performance-wise as you might think. UITableView reuses cells so really only the visible cells need be loaded into memory.
I'm also assuming you are able to access the forum via an API, right? In which case, you should be able to pre-load data immediately prior to loading the view and the UIWebViews will only be used for formatting. You can even load a CSS file from your app bundle when you loadHTMLString into your UIWebView so you're not loading that from a server every time.
All that being said, if you did have a lot of concurrently visible cells it might be a different story and I'd maybe consider only showing plain text in the UITableView index and displaying the rich formatting only when the user taps the cell to view the single post. This might also be better from a design standpoint as having a ton of differently formatted cells on screen could potentially end up looking a bit sloppy.
Also, this may be obvious (especially since you seem to be both performance and design conscious) but please don't use UIWebView for UI controls. Any time I see a UIWebView tab bar or fake navigation bar I cringe (ack, Netflix). For formatting though, a lot times it's the only way to fly if you're loading a lot of dynamic content from a server.
NSAttributedString+HTML already supports lazy loading of images. See the Demo that shows how to do that. It's reasonably fast but you want to hold of parsing the HTML for content that is not on screen.
It mostly depends on what UI you want to achieve. NSAS+HTML is meant for situations where you control the quality of the HTML (i.e. because you generate it yourself). There it affords you with an unprecedented level of control over the view hierarchy because you can embed your own custom views to show images.
In other cases where you cannot be sure about the quality of the HTML you have to use UIWebView and work around all of it's limitations, one being that it takes enormous amounts of RAM and it slow to show the contents. Also UIWebView is not thread-safe (because WebKit is not).
This is a question for iPhone development and I'm hopin someone can point me to the right direction on how i should go about implementing this.
I am trying to write a chat application that supports emoticons/smileys. Where the smiley/emoticon images are stored can be figured out later. I think few iphone applications out there are already doing this (i.e. skype + ebuddy(?)) but not sure what method they went for.
After searching around, there seems to be a few ways of doing this (i think):
bubble chat style which has been discussed before. UITableViewController with custom UITableViewCell. For emoticons, might have to do a whole bunch of calculations to determine where to stick a UIImageView for each emoticon.
Use UIWebView as the whole "window". Style it to look like bubble chat. Takes away any manual calculations on image smiley placements.
I have no idea what the performance is like for each of these two methods, how complex it can get etc, so any comments and guidance will help for sure. Cheers
If you use custom UITableViewCell, then I'd probably implement drawRect: instead of adding labels and images. One will probably take as long to implement as the other, but it will perform much better.
The UIWebView might be worth a short, although you will have to make sure that everything looks right there, too. Instead of using one big web page, I suggest simply throwing in a web view into each table view cell.
Personally I prefer the first approach, measuring and layout of text is not too complicated, but then I've never been the ultimate HTML guru.
I agree with #Eiko on making custom UITableViewCells, especially using drawRect instead of adding labels, images, etc.
If you used a UIWebView how would you handle updating it? A complete reload each time new text is sent? That seems like it will be a cause of issues. Once you get a long conversation reloading the entire UIWebView's contents will cause some flickering which isn't acceptable in my opinion. Also using a UIWebView would require you to have 2 complete copies of each conversation in memory. 1 as your backend data and 1 as the HTML. Where using a UITableView you have your backend data, and only enough of that will be duplicated that can fill 1 screen at a time.
I'm new to iPhone development, and I have a question on how to create a view for my application.
The view should display a problem (using formatted/syntax highlighted text), and multiple possible answers. The user should be able to click on an answer to validate it.
Currently, I am trying to use a UITableView embedding UIWebView as contentView. That allows me to display formatted text easily.
The problem is that it is a real pain to compute and adjust the height of the cells. I have to preload the webview, call sizeToFit, get its height, and update the cell accordingly. This process should be done for the problem and the answers (as they are HTML formatted text too).
It's such a pain that I am planning to switch to something else. I thought using only a big UIWebView and design everything in HTML. But I looked at some articles describing how to communicate between the HTML page and the ObjectiveC code. This seems to involve some awful tricks too...
So... that's it, I don't really know what I should do.
I guess some of you dealt with such things before, and would provide some greatly appreciated tips :)
The catch here is that the iPhone API does not yet support NSAttributedString so you can't just set the text to appear as you would like in a textview.
I saw one work around which essentially used individual UILabels to represent each attribute run. (Can't find the link now.) They used NSString UIKit extensions to calculate the position of the strings on the view and then used that to position the labels.
Another work around would be to draw the strings with their attributes to a UIImage and then just display the image. That would be the easiest solution I think.
In either case your going to have to basically recreate the data structure of an attributed string.
NSAttributedString does a lot of work for us. We really miss it when it is gone.
I want to implement a view in an iPhone application that is essentially like a rich text document. I need it to be click-editable, and I'd like to be able to embed graphic objects (either an overlaid view object, or manually drawn in graphic) with the text wrapping around. much like you would expect in a word processor. That's about the minimum functionality needed. Changing font for certain text would be a bonus (bold, size, etc).
UITextView would be a great start for me if it supported media like graphics embedded.
I'm still very new to Cocoa and Obj-C. Where should I start?
UITextView will not be nearly sufficient -- it has a very well-defined and simple functionality. That is an extremely complicated thing you're trying to do, wrapping text around an image -- you'll have to use to manually render the text in your drawRect method and do some very complex collision detection and calculate the string sizes etc. It's do-able, but extremely complicated.
Now, if you don't want the text to hug the image, but rather have the two appear on distinct lines, then you could fake this with a UITextView, then a UIImageView, then a UITextView, manually changing size and offset of each as the text changes...but this is a cheap hack and not exactly extensible. It could be sufficient for your needs, however.
UITextView does not allow rich formatting (bold, italics, different sizes, colors...), so that too would require a custom sort of text view.
Basically, it's a pretty big undertaking. If you're really committed, I recommend what Alex said -- get very, very comfortable with UIKit and Objective-C and iPhone coding in general. Then research how to make a rich text editor in other languages more suited to the functionality, and try porting that to the iPhone.
Hope this doesn't sound too discouraging. It's possible, but it won't be easy. And always bear in mind that the iPhone is a phone. Is it really the best platform for your application?
You might start with a much smaller, unrelated project. A viewer is no problem — start with UIWebView, which can render a RTF document for viewing. Creating a document editor, however, is no small task.