Develop Reference

Need advice on view layout for Google Glass app - a table with varying # rows which should fill the screen (dynamic text size)

I'm creating a Google Glass app and need to display a simple table. The table will have 2 columns and a varying # of rows.
I'd like the text size to be dynamic based on how many rows are in use. So if you have just 3 rows and the strings in the cells are short (in terms of length) the text size should be larger. If, on the other hand the view updates and now there are 6 rows and/or the string length in the cells is greater, the text size should be reduced.
Plainly put, the text size should be computed so that the text is as large as possible while still fitting the entire table on screen.
Any advice on how to create a layout to achieve this? I found the GridLayout but I think I'll need to dnyamically update it since the # rows can vary. Then there's the text size issue.

This is the kind of problem that is easy on the Web but hard on Android. So one approach might be to put a webview into your app and show an HTML table you generate locally and inject into the webview.
You might have reasons this won't work for you. If you need a more native approach this is a problem that has been solved in native Android apps, basically by measuring the font size to see if it will fit in a space iteratively. You start small and increase the size until it doesn't fit, then use the size before the one that didn't fit.
Here is a thread about that approach:
How to adjust text font size to fit textview
That will adress the difficult issue of text size.
Once that is solved the layouts are easy, many containers will work including GridLayout, TableLayout or even a series of nested LinearLayouts.

Reader app - use WebView or Canvas?

I'm writing one of those reader applications. I would like to know if you have opinions and arguments for and against using WebView and Canvas (with drawText()) to achieve it.
What are the requirements:
format text according to a few html tags: <p>, <strong>, <h3>, <br/>, <a>,
display images within the text (they are in <img> tags),
display the text in two columns on tablet devices,
paging the text (Google currents style)
The ones in bold are absolutely required. The latter are strongly desired, but I can drop them.
So as far as my knowledge goes:
WebView will be great when it comes to displaying the html formatted text. I also don't have to take care of loading images, tey will be loaded automatically with <img> tags (will they, even if I use loadData() instead of loadUrl()?). The problems begin if I try to page the text. Is there a possibility to count the size of the text in a WebView and reflow it into multiple pages (using ViewPager)?
Canvas is great when it comes to counting the size of the text, putting it into columns and pages. But I will have to handle all the HTML tags myself, format the text myself. What is even worse, I will have to extract images' urls, handle the downloading and putting them back to the text (reflowing the whole text every time they load). Am I right?
Can you point some other advantages and disadvantages of using them? Which would you choose? Or maybe something else? Or is there some lib which does at least some of the work for me?

Why not use the Textview combined with spanned text and viewpagers for the paging.

Present html content as dynamic "pages"

I'm building an e-Book reader for android. The content of an ebook is often divided into html files (epub) with one or may chapters in them.
I'm planning to build an e-book reader who divides the content of those files into different "pages". The problem is to know how many much text "fits" on one page and to calculate the correct amount of pages since that depends on a number of different factors, such as: font-size, word size, paragraphs, images, page-breaks, headlines etc.
Idealy i would have my text justified and selectable, and since that's not possible with normal TextView or EditText i must use a non-scrollable WebView.
So to sum it up, how can i "measure" how much text that fits on one "page" on my WebView? Or is there a different better approach to solve this? I saw that the Paint class as support for measure text and breakText.
Thanks!

Note : This answer does not use the webview as your display surface.
You can use the Canvas to draw each page. The canvas gives you it's height & width using which you can draw each line on the canvas using drawText based on the width & height available.
Basically you can calculate how many letters can fit in a line , take that many words , taking care you don't split any words and keep drawing the text.
If you break up the tasks to use different workers for each paragraph you can also probably make it fast.

Maybe you can do it like this
Text is being added and rendered inside WebView
In WebView, you can use Javascript to inspect the current state of DOM tree and extract measurements like width and height of individual elements
Javascript communicates back the size of the page back to WebView creator thru some callback
When Javascript detects that the page size threshold is exceeded it sends a signal for a page break needed
Android HTML5 Kindle does page breaking with Javascript so it is definitely possible.

Take a look at the source of FitText or perhaps here. Both figure how much text can fit in a given space. You may be able to borrow ideas from them and adapt for your purposes.

Is there a fill parent for Text Size?

I am trying to make a sign (the ones that drivers use at the airport to find someone "Mr Smith") and I wanted the sign to have the largest Font size possible, (its for a tablet), I could write a function to change the size depending on the length of the Text but is there a way of doing natively/better?
Thanks

The most flexible way is to create a custom view that draws the text in onDraw(). When drawing the text (with one of Canvas.drawText()) you will have to provide a Paint, and that would let you know the precise length of text, not just length of string (see Paint.measureText()).
This way you would have plenty of ways to calculate and redistribute the space (and it would totally rely on you how).
One way I can think of is calculating the length for a huge font size and then using the h/w ratio to see if I want to fill the screen in width or height.

Calculating Android TextView's text capacity

I have TextView with height and width as fill parent. Is it possible to find out how many characters can this layout hold?

Do you mean how many characters can be entered into the textview and still be fully visible without scrolling? For proportional fonts, that will depend on the specific characters typed, including where the line break opportunities are. I don't think there's a simple way to compute that.