I am attempting to work on an app that highlights certain key words. For this reason, I am looking at using either CoreText or UIStringDrawing to highlight these words (As in bold/underline/italicize/color) since UITextView doesn't seem to have these facilities (And I haven't had any luck with CATextLayer).
In either case I am able to successfully manipulate and draw the string. (I.E- I can find my important words in a string and apply the appropriate traits).
The problem I am having is that when text is drawn this way, it cannot be interacted with directly. Seeing as the user will be able to delete/add text to the text view in question, this is an important thing to have.
At the moment I have stuck my drawing routines into the drawRect: method of a UITextView subclass (Mostly just to see that I can do what I want). Does UITextView have a different method that can be overridden so that it uses my code to render its string? If not, how might I go about doing what I've described?
For an example of what I am talking about, look at how the Notes app finds and highlights phone numbers and addresses. I'm not looking for phone numbers or addresses, but it gets the point across.
After a bit of additional reading, it seems that you need to subclass/override a LOT of methods in order to create your own text view whose text you can draw. Apple's docs touch on it, but they don't go much into detail.
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.
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.
I would like to have a UITextField or UITextView in where as I do some input, alternatives will appear something similar to when you type an address in Mail Application, alternatives appear down and is possible tap them so get a better input user interface.(since there is no need to type the complete word or address or phone number)
I do know how to fetch data from Address Book framework, also how to input text in UITextField/UITextView and its delegates but I don't know what kind of structure to use for fetching and showing data as the user do his/her input.
I know basic CoreData if this matters,
I hope I can get some help.
UPDATE (2010/3/10):
I don't have problem make a native-like GUI but I am asking about the algorithm, does any body knows what kind algorithm is best for this thing? maybe some binary tree?
Or should I just fetch data from coredata everytime?
Thanks
Ignacio
UPDATE (2010/03/28):
I've been very busy these days, so I have not tried UISearchResults but it seems fine to me. BUT I wonder was there a necessity of deletion of the wining answer? I don't think is fair my reputation went down and couldn't see the winning answer. ;(
You don't need some advanced algorithm to do this kind of thing... if you want to search the address book, then you can do so each time the user types in a character (or however frequent you need to seach). To do this, just take a look at the UISearchDisplayController class. I learned how to do almost the exact thing by looking at Apple's TableSearch sample app.
That app searches a list of objects using different fields (All, Device, Desktop, Portable)... so you could adapt it to Address Book fields (First Name, Last Name, Address...). The only thing you need to change is the search within the Address Book. I don't know exactly what your requirements ask for but this should be what you need to get it done. If you have any trouble with the code let me know... but this example really helped me, so hopefully it works for you.
I was looking for the same thing a while ago. Something that people kept suggesting was the Three20 project (google it).
For my needs this was overkill because it requires the whole project to build and I didn't want the whole project. Plus it's more fun to try it yourself :)
I ended up starting from scratch and making my own:
I started out with a subclass of a UIScrollView to contain the different controls. I subclassed a UITextField and overrided "editingRectForBounds" to support multiple lines. The bit where the contacts are displayed is just a UITableView with a background color of:
[UIColor colorWithRed:0.92 green:0.92 blue:0.92 alpha:1];
And separator color:
[UIColor colorWithWhite:0.85 alpha:1];
This and the use of a shadow makes it looks like it's sunken slightly under the UITextField. I create the shadow with a custom UIView, loading it once and hiding it when required, but it works just as well with an image.
Finally, I made the blue pill shapes with a custom UIView which can intercept "touchesBegan" to know when they should change color.
Adding them is a simple matter of calculating where they need to go and using:
[myTextField addSubview:myBlueView];
Hope that helps!