Rich text components in Flutter - flutter

I would like to make a hybrid app using Flutter. One particular kind of component I'm looking at sounds something like this:
A Chinese character like 家 (which means home) is shown
When an user clicks on the character, it can display its pronunciation (jia)
The user also has the option to click to play the pronunciation
The user can also choose to open a window where an animation of how the character is being written is played.
So for a sentence like: 蓝天是白云的家(literally translated as: The blue sky is the home of the white clouds), each of these 7 characters can be individually clicked and users can choose to display / play pronunciation / show how they are written.
Normal static text won't be rich enough to display all these information. My current idea is to make every character a customized widget with such data embedded within.
This task can be quite huge if each Chinese character (there are approximately 5000 characters that are commonly used) has its own rich data format.
Any suggestions on how to approach this problem in an efficient manner in Flutter?
Thanks in advance!

There are a few ways to do this. Using widgets could definitely be an option, but that's probably going to cause you issues in the long run.
Let's break this into two parts:
1: Displaying the text
Instead of using widgets, I'd suggest using a RichText with many TextSpan children. You could create a custom class that accepts the string, splits it into characters, and puts each character in its own TextSpan. By using TextSpan.recognizer. You could then either use a TapGestureRecognizer with onTap to show the information when tapped if you don't need the position at which it was tapped, or onTapDown/onTapUp if you do (for example if you want to show a popup right where the click happened as opposed to something like a bottom sheet that comes up).
2: Showing the information
Because you're wanting to deal with a large amount of characters, I'd suggest not doing it all in code but instead handling the characters in some other sort of format that can easily be manipulated, for example JSON. That way you can do things like splitting the data it into blocks and loading them as needed, and/or getting them from a web server.
Your data could look something like:
{
"家": {
"pronunciation": "jia",
"audio": "path/to/sound.m4a",
"animation": "path/to/animation.gif"
},
...
}
You could theoretically even do things like start loading the pronunciation files when the character is first shown or when they click on it.
When the character is tapped, you could:
check if data in cache
load the data if needed from network/disk
open bottom sheet or popup displaying the pronunciation info + buttons for audio & drawing animation

Related

How to replicate tumblr tags in flutter

I am trying to replicate the mobile tag-adding mechanism that tumblr has. I have included a picture of the screen I am talking about below.
I want to replicate the following features:
Chips are inline with text field. Text field resizes dynamically to either take the remainder of the line, or take up the next line if the content is too long
Text is turned into a chip when a comma is added (e.g. If I am typing "dog", and then I type "dog,", A "dog" chip will be created
Long chips cut off content with ellipses
Chips can be deleted with backspace
There is no text field underline decoration
Chips fill up row then wrap to next row (and entire container scrolls if there are too many rows to display simultaneously)
There are some libraries that already exist to allow a text input field with chips, but they have a lot of other features that I'm not interested in right now like the recommendation system etc, and generally just don't look the way I want with regards to multiple lines and text wrapping etc. If anyone knows how to replicate the example below, I would really appreciate it!

Scrollable view with text and ability to do something when specific phrase is tapped

I am trying to implement a view which will load text from sqlite database (every sentence in a text will have unique tag in database) and will allow to execute some code while sentence is clicked (on-click executed method should then scroll clicked sentence to the center of the screen and change it's color/background color/font size to emphasize it)
Is it possible without using webview and js/js-native bridge? Which approach should be taken to implement such a view? Any help and comments highly appreciated!
Hmm, you could also considering using NSAttributedString together the Core Text Framework and attribute each sentence and attach some extra info about. Next you lookup the attribute below the tap position of the view. Once you have that you can retrieve the extra info again and do whatever you want with the tap.
After the tap you could then alter the properties of that part of the text. E.g. different font colour etc.
This tutorial on the internet looked interesting:
http://www.raywenderlich.com/4147/how-to-create-a-simple-magazine-app-with-core-text

Length of text that can just fit into one screen without scrolling

I find some iphone book apps have such feature:
One screen one page of text without scrolling. The text can just fit into the whole screen with linebreaks and indentations.
I'm curious of how to implement this. How could I decide the length of text that just fit into the screen. And also, given the whole text, I can calculate out the number of pages.
If this is not possible to be done on iPhone(runtime?), then is it possible to process the text before storing it in app? I mean I calculate how many pages I need(how to split the raw text), probably how many lines per page.
I think this is what you are looking for
iPhone SDK: How do you measure the width and height of a string using Quartz?
The accepted answer gives methods you can call on NSString to calculate sizes
What I did for TouchTomes' books was have two iPhone apps. One was the reader that showed up on the App Store. The other was a renderer that calculated what could fit on each page, that only needed to be run in the simulator to create a book DB that the reader could use.
It would throw up a bunch of text, say 100 words, and see if that overflowed or underflowed. If it underflowed, more text was added (say 20 words) and it would binary search until it found exactly how much text would fit. Then it stored in a SQLite DB a row saying "page 12 shows words 100-228" for example. The app would go through this for each font. Another table held all the words in individual rows (!). An optimization step would chop that table down, combining words that always appeared on the same page no matter what font.
I used a Webkit display so the book could include HTML formatting. Now that really complicated the page breakup (e.g. had to keep italics going from page to page) but it let me include some fancier formatting in the text.
Then the reader app had very little to do to display pages; from the page id look up what range of words go on that page, then throw that text up into a webkit view. The user could jump between pages all over the book very quickly, all the hard CPU work had already been done by the rendering app.

Large scrollview table with buttons

We are trying to write a training manual application for the iPhone. On the top half of the screen is a diagram of a car engine, on the bottom half is some text. At the user repeatedly hits a "next" button, we highlight different parts of the engine, and in concert we highlight different parts of the descriptive text below.
We basically want "living text" in the text half, with the illustration following along on top to where the reader is in the text. What we'd like from the text is 1. user can scroll it using their thumb so possibly a UIScrollView 2. the software can explicitly drive a scroll to any part of the text (when they hit the "next" button). 3. the words in the text are interspersed with hotlinks e.g. "this is the camshaft... this is the piston..." and the user should be able to click on any of the keywords like camshaft, piston, and have the diagram highlight that. (The problem is not highlighting the diagram, its capturing the click). The text would have 300~400 buttons/links/keywords and about 600 words of text.
Since this is fairly similar to using a web browser, we tried using Apple's version of webkit using a UIWebView and handleOpenURL to register a service back to the app itself. But Webkit for internal links a popup comes up asking permission to access that link. Every single the user wants to go to a link (in our case just an internal event that we'd intercept so that we can highlight e.g. the camshaft). Tried to intercept the event from the HTML view, but that didn't work.
It seems like the best we can do is to abandon scrolling text, and make the text part more like flash cards or a power point presentation, breaking the text into custom UIViewCells with buttons inside a UIScrollView. However, this would impose an annoying constraint on the author that they would have to write everything to fit in the UIViewCells, sort of chunky.
Any ideas would be appreciated.
This is definitely something you can use a UIWebView for. Don't use handleOpenURL, rather, set your viewController as the webview's delegate, and override -webView:shouldStartLoadWithRequest:navigationType:. When this gets called, check the request, and pull out your link data from there.
It would probably be easier to implement that completely in JavaScript in the document you load in a UIWebView. You would have to use JavaScript (i.e. [UIWebView stringbyevaluatingjavascriptfromstring:]) anyway to achieve things like scrolling to a certain position.

Easy way to scroll overflow text on a button?

Does anyone have any examples or resources where i might find information on scrolling text which is too long to display in a button control? I'm thinking something along these lines.
Display as much text will fit within the current rect with a '...' at the end to signify overflow.
Pause for say 1 second then slowly scroll the text to the right edge displaying the right part of the string.
Display as much text will fit within the current rect with a '...' at the beginning to signify overflow.
Start the whole thing over in reverse.
Is there an easy way to do this using the "core" or built in "animation" frameworks on a certain mobile device?
[edit]
Iwanted to add some more details as i think people are more focused on wether or not what i'm trying to accomplish is appropriate. The button is for the answers on a trivia game. It does not perform any speciffic UI function but is for displaying the answer. Apple themselves is doing this in their iQuiz trivia game on the iPod Nano and i think its a pretty elegant solution to answers that are longer than the width of my button.
In case its the '...' that is the difficult part of this. Lets say i removed this requirement. Could i have the label for the button be full sized but clipped to the client rect of the button and use some animation methods to scroll it within the clipping rect? This would give me almost the same effect minus the ellipses.
Here's an idea: instead of ellipses (...), use a gradient on each side, so the extra text fades away into the background color. Then you could do this with three CALayers: one for the text and two for fade effect.
The fade masks would just be rectangles with a gradient that goes from transparent to the background color. They should be positioned above the text layer. The text would be drawn on the text layer, and then you just animate it sliding back and forth in the manner you describe. You can create a CGPath object describing the path and add it to a CAKeyframeAnimation object which you add to the text layer.
As for whether you think this is "easy" depends on how well you know Core Animation, but I think once you learn the API you'll find this isn't too bad and would be worth the trouble.
Without wishing to be obtuse, maybe you should rethink your problem. A button should have a clear and predictable function. It's not a place to store and display text. Perhaps you could have a description show on screen with a nice standard button below?
Update with source code example:
Here is some ready to use source code example (actually a full zipped Xcode project with image and nib files and some source code), not for the iPhone, not using Core Animation, just using a couple of simple NSImages and a NSImageView. It is just a cheap hack, it does not implement the full functionality you requested (sorry, but I don't feel like writing your source code for you :-P), horrible code layout (hey, I just hacked this together within a couple of minutes, so you can't expect any better ;-)) and it's just a demonstration how this can be done. It can be done with Core Animation, too, but this approach is simpler. Composing the button animation into a NSImageView is not as nice as subclassing a NSView and directly paint to its context, but it's much simpler (I just wanted to hack together the simplest solution possible). It will also not scroll back once it scrolled all the way to the right. Therefor you just need another method to scroll back and start another NSTimer that fires 2 seconds after you drew the dots to the left.
Just open the project in Xcode and hit run, that's all there is to do. Then have a look at the source code. It's really not that complicated (however, you may have to reformat it first, the layout sucks).
Update because of comment to my answer:
If you don't use Apple UI elements at all, I fail to see the problem. In that case your button is not even a button, it's just a clickable View (NSView if you use Cocoa). You can just sub-class NSView as MyAnswerView and overwrite the paint method to paint into the view whatever you wish. Multiline text, scrolling text, 3D text animated, it's completely up to your imagination.
Here's an example, showing how someone subclassed NSView to create a complete custom control that does not exist by default. The control looks like this:
See the funny thing in the upper left corner? That is a control. Here's how it works:
I hate to say that, as it is no answer to your question, but "Don't do that!". Apple has guidelines how to implement a user interface. While you are free to ignore them, Apple users are used to have UIs following these guidelines and not following them will create applications that Apple users find ugly and little appealing.
Here are Apple's Human Interface Guidelines
Let me quote from there
Push Button Contents and Labeling
A push button always contains text, it
does not contain an image. If you need
to display an icon or other image on a
button, use instead a bevel button,
described in “Bevel Buttons.”
The label on a push button should be a
verb or verb phrase that describes the
action it performs—Save, Close, Print,
Delete, Change Password, and so on. If
a push button acts on a single
setting, label the button as
specifically as possible; “Choose
Picture…,” for example, is more
helpful than “Choose…” Because buttons
initiate an immediate action, it
shouldn’t be necessary to use “now”
(Scan Now, for example) in the label.
Push button labels should have
title-style capitalization, as
described in “Capitalization of
Interface Element Labels and Text.” If
the push button immediately opens
another window, dialog, or application
to perform its action, you can use an
ellipsis in the label. For example,
Mail preferences displays a push
button that includes an ellipsis
because it opens .Mac system
preferences, as shown in Figure 15-8.
Buttons should contain a single verb or a verb phrase, not answers to trivia game! If you have between 2 and 5 answers, you should use Radio Buttons to have the user select the answer and an OK button to have the user accept the answer. For more than 5 answers, you should consider a Pop-up Selector instead according to guidelines, though I guess that would be rather ugly in this case.
You could consider using a table with just one column, one row per answer and each cell being multiline if the answer is very long and needs to break. So the user selects a table row by clicking on it, which highlights the table cell and then clicks on an OK button to finish. Alternatively, you can directly continue, as soon as the user selects any table cell (but that way you take the user any chance to correct an accidental click). On the other hand, tables with multiline cells are rather rare on MacOS X. The iPhone uses some, but usually with very little text (at most two lines).
Pretty sure you can't do that using the standard API, certainly not with UILineBreakMode. In addition, the style guide says that an ellipsis indicates that the button when pressed will ask you for more information -for example Open File... will ask for the name of a file. Your proposed use of ellipsis violates this guideline.
You'd need some custom logic to implement the behaviour you describe, but I don't think it's the way to go anyway.
This is not a very good UI practice, but if you still want to do it, your best bet is to do so via a clickable div styled to look like a button.
Set the width of the div to an explicit value, and its overflow to hidden, then use a script executing on an interval to adjust the scrollLeft property of this div.