I would like to implement rich format text views as are demonstrated in Instagram. Following is a screenshot.
Specifically, my goals are:
Words at different positions of the same text view may have different font sizes, font colors and font styles(bold, italic, etc).
Touch events (long press, touch down, etc) can be detected in the delegate callbacks. Information (which word is touched, whether it's a long press or a touch down, etc) can be gathered in such callback methods.
Big frameworks like Three20 are out of the question. Small, independent libraries are highly preferred. Low level Cocoa Touch APIs may also be OK if it won't take me more than a few days to wrap them up.
Any suggestions are highly appreciated.
NSAttributedString lets you do this. If you have access to the iOS 5 developers cookbook by Erica Sadun there is a recipe for a wrapper around NSMutableAttributedString which makes it simple to add text piece by piece, changing attributes as you go.
Here is the source on Erica's githuib
Finally found an ideal open source solution (supports both iOS 5.0 and iOS 6): the OHAttributedLabel, which is capable of both rich format and touch handling.
https://github.com/AliSoftware/OHAttributedLabel
Related
I'd like different words in a UILabel to be different colors. Does this mean each word will need to be a different UILabel? I'm guessing yes, though sure would be nice to just put color codes in the label somehow, you know? I guess I'm a bit spoiled by text markup in HTML.
There is no proper UIRichTextView in iOS. It's high on my wish-list for iOS 6 (and there's some reason to believe we may get it then due to the release of Pages).
Your options are to use multiple UILabel views, NSString UIKit Additions, Core Text, UIWebView, or one of a few third-party frameworks such as:
NSAttributedString-Additions-for-HTML
CoreTextWrapper
OHAttributedLabel
OmniUI
All of the current solutions have different problems. The most common problem is that it's hard to get select and copy functionality to work with rich text unless you use a web view. Web views are incredibly annoying because they're asynchronous and you have to do a lot of your interactions in JavaScript.
I wish there were a better answer.
(Obligatory shilling: This topic is covered in depth in Chapter 18 of iOS 5 Programming Pushing the Limits.)
UILabel doesn't support segmented formatting (the entire thing can only have one format).
Have a look at OHAttributedLabel, which does what you want.
As far as I'm aware you'd need to have separate labels for each different coloured word. Depending what you're trying to do you may be able to make use of myLabel.textColor to change the colour of the periodically or on events etc.
If you implement UITextInput on your custom view and - say - use CoreText to render the text you get to a point where you can draw your own cursor and selection/marking and have that fully working with the hardware keyboard. If you switch to Japanese input then you see the marking, but there's something curious: if you long press into the marking you get the rectangular system loupe and selection handling without having to deal with the touches yourself.
What I don't get why we would have to implement our own touch handling for the selection, draw our own loupes etc. It's working for marking! So what do I have to do to get the standard gesture recognizers added to my custom view as well?
the one sample on the dev site only has a comment about that user selection would be outside the scope of the sample. Which would indicate that indeed you have to do it yourself.
I don't think that it is in Apple's interest that all developers doing their own Rich Text editor class keep doing their own selection handling code, let alone custom drawing of the round and rectangular loupes?! Granted you can try to reverse engineer it such that it comes really close, but that might give users a strange feeling if the selection mechanics differ ever so slightly.
I found that developers are split in two groups:
1) rapes UIWebView with extensive JavaScript code to make it into an editor
2) painstakingly implements the selection mechanics and loupe drawing themselves
So what is the solution here? Keep submitting Radars until Apple adds this missing piece? Or is this actually already existing (as claimed by the aforementioned engineer I met) and we are just too stupid to find how to make use of it, instead resorting to doing everything (but marked text) manually?
Even the smart guys at Omnifocus seem to think that the manual approach is the only one working. This makes me sad, you get such a great protocol, but if you implement it you find it severely crippled. Maybe even intentionally?
Unfortunately the answer to my question is: YES. If you want to get selection mechanics on a cusrom view you have to program it yourself.
As of iOS 6 you can subclass UITextView and draw the text yourself. According to an Apple engineer this should provide the system selection for you.
Looking for some catalog/gallery(not UICatalog, just images), where I can see preview of each UI element in iPhone SDK, along with corresponding class name(eg datetime picker, calendar, the black switch bar on bottom). This will give me rough idea on which UI elements I can use in my app and go read about corresponding class.
I would highly recommend reading the iPhone Human Interface Guidelines Document. It's produced by Apple, and has a ton of great advice on how to craft interfaces as well as descriptions and guides for the standard UI elements.
You can also check out the UIKit Framework Reference, and the wiki at CocoaDev. If you need images, teehan+lax have a great PSD template for mockups
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.
Is it possible to use the CFAttributedString type to draw formatted text on the iPhone? I see it in the documentation, but I can't figure out how to actually draw it to a context.
Three20 has a formatted text field. Basically Joe Hewitt implemented a light HTML interpreter to render the text, so it is much faster than a webview. fast enough to be used in a tableview.
The workaround is to use a WebKitView. Format your text as HTML and display in a mini web view at whatever size you need.
Actually, it turns out this is answered in the iPhone documentation, I just didn't read it carefully enough:
iPhone OS Note: While Core Foundation on iPhone OS contains CFAttributedString, there are no additions to the APIs in UIKit to add specific attributes such as font, style, or color, and there are no APIs to draw attributed strings.
There you go, no free formatted text. Bummer.
Kyle
There's an undocumented method on TextView to pass in HTML formatted text (it's really a kind of web view underneath). A number of apps in the store make use of it, just make sure your app works without it there.