David's Blog

create iOS app using Promotion Mar 24

The Goal

Create an iOS app as quickly as we can.

Project Setup

Create a new app

promotion new membershipapp

run tests automatically

gem install when-files-change
when-files-change "clear && bundle exec rake spec"

write test cases

The Promotion...

tips learn from confident ruby Mar 24

The book confident ruby

After reading the book confident ruby, I watch the screen cast with that book and learned following tips

use eachwithobject instead of initialize an empty object before the each

topics_list = []
another_list.each do |i|
...

Deploy R application to shinyapps.io Mar 18

An R hosting Service

Today I got an invitation for ShinyApps.io testing. This seems to be very useful because other PaaS like Heroku not allowing install R.

Installation

Just follow the guide from https://github.com/rstudio/shinyapps/blob/master...

Try bluemix android SDK with jruby Mar 17

Install the SDK

Create the project

ruboto gen app -t 14 --package org.ruboto.example.bluemix

Download SDK

The Web page javascript failed to download in Chrome browser, but open the console, and you can see the download link is: http://mbaas-catalog...

Run microsoft window virtual machine for free Mar 16

My laptop run linux but still need windows

Although I am not using windows in development and other daily job. I still need to be able to use windows some times. But I don’t want to pay for the windows. And I don’t want to use some cracked windows...

Record terminal session using asciinema Mar 14

My IDE is based on the Terminal

Install asciinema

sudo pip install --upgrade asciinema

Usage

Authenticate yourself

In order to be able to delete or edit your terminal screencast, it require to login first. Use the below command and follow the...

Update time for raspberry pi Mar 13

The date problem

The raspberry pi doesn’t has a real time clock, so every time start the raspberry pi, we have to resest the time.

manually set the time from ntp server

sudo /etc/init.d/ntp stop
sudo ntpdate 1.cn.pool.ntp.org

Solution 2: set the...

Delegate in ruby Mar 12

Serveral ways to delegate in Ruby

There are serveral ways to delegate in Ruby:

1. SimpleDelegator
2. DelegateClass
3. Delegator
4. forwardable module

SimpleDelegator

A concrete implementation of Delegator, this class provides the means to delegate all supported...

Using R in web development Mar 11

Statistic Tool: R

I have been want to use R in my work for a long time. But seem it is not so easy to combine it into the normal work flow very easily.

Now we have a web development using R and Bootstrap: Shiny

Shiny seems would be very useful for...

No Backend Development Mar 9

Backend As A Service

Recently I have used some Backend As A Service(BaaS) platform to make the development faster. How can it be faster than not doing. So for some very small demos, I tried firebase. It seems good. Only one thing is missing, it dont...