Author: user

If you mount the guest additions and see a warning about missing kernel headers, and the additions don’t seem to work, and then after trying to launch the guest additions CD again you get VERR_PDM_MEDIA_LOCKED error and everything starts going downhill from there – this is the solution that worked for me:

1. Reinstall Ubuntu

2. Before installing the guest additions:

sudo apt-get update
sudo apt-get install build-essential linux-headers-`uname -r` dkms

3. Now launch the guest additions CD

Update Dec 5th 2014: Fixed and updated the code.
Update Mar 9th 2017: Updated the code to handle null values in CSV.

This is a simplified Lua script to read and write CSV files. It assumes the separator character does not exist in one of the values.

I don’t know why I couldn’t find a simple code snippet to do this on the net, but sometimes it’s just faster to write it than to search for it. Hopefully this will save you that time too:

--[[
-------------------------------
Save this file as simplecsv.lua
-------------------------------

Example use: Suppose file csv1.txt is:

1.23,70,hello
there,9.81,102
x,y,,z
8,1.243,test

Then the following
-------------------------------------
local csvfile = require "simplecsv"
local m = csvfile.read('./csv1.txt') -- read file csv1.txt to matrix m
print(m[2][3])                       -- display element in row 2 column 3 (102)
m[1][3] = 'changed'                  -- change element in row 1 column 3
m[2][3] = 123.45                     -- change element in row 2 column 3
csvfile.write('./csv2.txt', m)       -- write matrix to file csv2.txt
-------------------------------------

will produce file csv2.txt with the contents:

1.23,70,changed
there,9.81,123.45
x,y,,z
8,1.243,test

the read method takes 4 parameters:
path: the path of the CSV file to read - mandatory
sep: the separator character of the fields. Optionsl, defaults to ','
tonum: whether to convert fields to numbers if possible. Optional. Defaults to true
null: what value should null fields get. Optional. defaults to ''
]]

module(..., package.seeall)

---------------------------------------------------------------------
function string:split(sSeparator, nMax, bRegexp)
    if sSeparator == '' then
        sSeparator = ','
    end

    if nMax and nMax < 1 then
        nMax = nil
    end

    local aRecord = {}

    if self:len() > 0 then
        local bPlain = not bRegexp
        nMax = nMax or -1

        local nField, nStart = 1, 1
        local nFirst,nLast = self:find(sSeparator, nStart, bPlain)
        while nFirst and nMax ~= 0 do
            aRecord[nField] = self:sub(nStart, nFirst-1)
            nField = nField+1
            nStart = nLast+1
            nFirst,nLast = self:find(sSeparator, nStart, bPlain)
            nMax = nMax-1
        end
        aRecord[nField] = self:sub(nStart)
    end

    return aRecord
end

---------------------------------------------------------------------
function read(path, sep, tonum, null)
    tonum = tonum or true
    sep = sep or ','
    null = null or ''
    local csvFile = {}
    local file = assert(io.open(path, "r"))
    for line in file:lines() do
        fields = line:split(sep)
        if tonum then -- convert numeric fields to numbers
            for i=1,#fields do
                local field = fields[i]
                if field == '' then
                    field = null
                end
                fields[i] = tonumber(field) or field
            end
        end
        table.insert(csvFile, fields)
    end
    file:close()
    return csvFile
end

---------------------------------------------------------------------
function write(path, data, sep)
    sep = sep or ','
    local file = assert(io.open(path, "w"))
    for i=1,#data do
        for j=1,#data[i] do
            if j>1 then file:write(sep) end
            file:write(data[i][j])
        end
        file:write('\n')
    end
    file:close()
end

---------------------------------------------------------------------

Using the inappbrowser plugin:

what should be in your config.xml is:

    <feature name="InAppBrowser"> 
       <param name="android-package" value="org.apache.cordova.inappbrowser.InAppBrowser"/>
    </feature>

and not

    <feature name="InAppBrowser"> 
       <param name="android-package" value="org.apache.cordova.InAppBrowser"/>
    </feature>

Also, if you want to use the back button handler on Android, make sure you have the following in your config.xml

    <feature name="App">
        <param name="android-package" value="org.apache.cordova.App" />
    </feature>

Another issue (not related to Cordova gotchas) is adb devices returning a status of offline for recognised Android devices connected via USB. There can be multiple reasons that cause this, but what worked in my case was:

1. kill the adb service running on your PC
2. Disable USB debugging on your Android device and remove the USB from your PC
3. Restart your Android device
4. Enable USB debugging on your Android device
5. Connect the USB cable from your Android device to your PC

6. run ‘adb devices’ from the terminal

Instead of reading the many pages explaining endless details, the following explanation is exactly the sort I like – summarising only the things you need to get going:

http://ionicframework.com/docs/guide/publishing.html

While you’re there, it’s worthwhile to look at ionic as well.

Let me save you a lot of time: The Cordova Media plugin (org.apache.cordova.media) does not work well on Android and Windows Phone 8, at least in the version released with Cordova 3.1 (and I don’t see any indication of a change in the latest release either).

On Android I assume media resources are not released by the plugin since after a few plays, the audio does not play anymore unless the application is restarted. On Windows Phone 8, the audio sort of plays, but causes the application to behave very strangely (unrelated Javascript callbacks are not invoked, probably due to threading issues and extremely sluggish behaviour in general)

What I did to play audio in a Cordova application was the following:

For Android, iPhone – use the following plugin:
cordova plugin add https://github.com/triceam/LowLatencyAudio

For Windows Phone 8, create a static HTML5 audio tag, get a pointer to it from the DOM (e.g, by getElementById) and just use the ‘play’ method on the returned object whenever you want to play the audio.