Taewon's road not taken

실무에 바로 적용하는 안드로이드 프로그래밍 (제 2판)

match_parent = 자신의 부모만큼의 크기가 된다.

wrap_content = 자신이 갖는 콘텐츠에 필요한 크기가 된다. 

문자열 값을 위젯에 직접 지정할 수도 있으나 다른 파일에 관리하는게 좋다. 

모든 프로젝트에는  strings.xml이라는 디폴트 문자열 파일이 포함된다. (strings는 res/values/strings.xml)

android:id="@+id/true_button" 이렇게 선언해주면 소스로 사용할 수 있다. 

안드로이드 애플리케이션을 실행하려면 실제 장치나 또는 안드로이드 가상 장치(Android Virtual Device AVD)가 필요하다. 

Tools -> AVD Manager

안드로이드 애플리케이션도 모델 뷰 컨트롤러 아키텍쳐에 맞추어 설계된다. 

mdpi (~60dpi)< hdpi(~240dpi) < xhdpi(~320 dpi) < xxhdpi (~480dpi)

@+id = id 선언

@string = xml string

@drawable = drawable resource 참조

생명주기 - 실행, 중지, 중단.

text-align for text placement.

relative length unit (%, em) and absolute length unit(px).

rgba(r, g, b, o); rgb + opacity 1~0.

box-shadow: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);

text-transform to transform texts.

:hover when mouse is placed over.

background: linear-gradient(

      53deg,

      #ccfffc,

      #ffcccf); good color

transform: scale(number); for resizing

animation effect basic codes:

div {

    height: 40px;

    width: 70%;

    background: black;

    margin: 50px auto;

    border-radius: 5px;

  }

  #rect {

    animation-name: rainbow;

    animation-duration: 4s;

  }

  @keyframes rainbow{

    0%{background-color: blue;}

    50%{background-color: green;}

    100%{background-color: yellow;}

  }

Making button more interactive!

button {

    border-radius: 5px;

    color: white;

    background-color: #0F5897;

    padding: 5px 10px 8px 10px;

  }

  button:hover {

    animation-name: background-color;

    animation-duration: 500ms;

    /* add your code below this line */

    animation-fill-mode: forwards;

    /* add your code above this line */

  }

  @keyframes background-color {

    100% {

      background-color: #4791d0;

    }

  }

Moving ball from left to right:

#ball {

    width: 70px;

    height: 70px;

    margin: 50px auto;

    position: fixed;

    left: 20%;

    border-radius: 50%;

    background: linear-gradient(

      35deg,

      #ccffff,

      #ffcccc

    );

    animation-name: fade;

    animation-duration: 3s;

  }

  @keyframes fade {

    50% {

      left: 60%;

      opacity: 0.1;

    }

  }

Bouncy ball:

<style>

  #ball {

    width: 100px;

    height: 100px;

    margin: 50px auto;

    position: relative;

    border-radius: 50%;

    background: linear-gradient(

      35deg,

      #ccffff,

      #ffcccc

    );

    animation-name: bounce;

    animation-duration: 1s;

    animation-iteration-count: infinite;

  }

  @keyframes bounce{

    0% {

      top: 0px;

    }

    50% {

      top: 249px;

      width: 130px;

      height: 70px;

    }

    100% {

      top: 0px;

    }

  }

</style>

<div id="ball"></div>

Heart Beat: 

<style>

  .back {

    position: fixed;

    padding: 0;

    margin: 0;

    top: 0;

    left: 0;

    width: 100%;

    height: 100%;

    background: white;

    animation-name: backdiv;

    animation-duration: 1s;

    animation-iteration-count: infinite;

  }

  .heart {

    position: absolute;

    margin: auto;

    top: 0;

    right: 0;

    bottom: 0;

    left: 0;

    background-color: pink;

    height: 50px;

    width: 50px;

    transform: rotate(-45deg);

    animation-name: beat;

    animation-duration: 1s;

    animation-iteration-count: infinite;

  }

  .heart:after {

    background-color: pink;

    content: "";

    border-radius: 50%;

    position: absolute;

    width: 50px;

    height: 50px;

    top: 0px;

    left: 25px;

  }

  .heart:before {

    background-color: pink;

    content: "";

    border-radius: 50%;

    position: absolute;

    width: 50px;

    height: 50px;

    top: -25px;

    left: 0px;

  }

  @keyframes backdiv {

    50% {

      background: #ffe6f2;

    }

  }

  @keyframes beat {

    0% {

      transform: scale(1) rotate(-45deg);

    }

    50% {

      transform: scale(0.6) rotate(-45deg);

    }

  }

</style>

<div class="back"></div>

<div class="heart"></div>

pretty background:

background: linear-gradient(black, #000099, #66c2ff, #ffcccc, #ffeee6);

  }

final :

<style>

  .balls {

    border-radius: 50%;

    position: fixed;

    width: 50px;

    height: 50px;

    top: 60%;

    animation-name: jump;

    animation-duration: 2s;

    animation-iteration-count: infinite;

  }

  #red {

    background: red;

    left: 25%;

    animation-timing-function: linear;

  }

  #blue {

    background: blue;

    left: 50%;

    animation-timing-function: ease-out;

  }

  #green {

    background: green;

    left: 75%;

    animation-timing-function: cubic-bezier(0.311, 0.441, 0.444, 1.649);

  }

  @keyframes jump {

    50% {

      top: 10%;

    }

  }

</style>

<div class="balls" id="red"></div>

<div class="balls" id="blue"></div>

<div class="balls" id="green"></div>

Three important properties control the space that surrounds each HTML element: padding, margin, and border.

css selection priority

class < id < inline style < !important

colors can be represented by 3 ways:

color name ex. color: red;

hexdeciaml ex. color: #ff0000; (red green blue, two placement per color)

rgb(0,0,0) method ex. color: rgb(255, 0, 0);

you can create css variable by following:

--penguin-skin : gray;

can apply created css variable by :

background-color : var(--penguin-skin);

To make use of inheritance, CSS variables are often defined in the :root element.

(not sure) add this to resize, redecorate css according to size:

 @media (max-width: 350px) {

    :root {

      /* add code below */

      --penguin-size: 200px;

      --penguin-skin: black;

      /* add code above */

    }

  }

Create a .pem key from aws

ssh-add ~/downloads/ssh_taewon/MyKeyPair.pem

chmod 400 mykeypair.pem

Create a .ppk to connect to filezilla

on mac use this command : 

puttygen mykeypair.pem -o mykepair.ppk

filezilla -> 

select sftp protocol and select key file, and then browse to your created .ppk file.

To run a project on ec2 server, you need to do the following:

1. connect to ec2 instance

sudo ssh -i /users/taewon/downloads/ssh_taewon/mykeypair.pem ec2-user@ec2-13-125-250-142.ap-northeast-2.compute.amazonaws.com

2. download tomcat

sudo yum list tomcat*

sudo yum install tomcat7-webapps.noarch

sudo service tomcat7 start

3. put a war project into accessible folder and by command, move it to /var/lib/tomcat7/webapps+

4. start a server

service tomcat7 start

5. check the log

tail -f catalina.out

6. when starting the server, if project placed right, it should automatically unzip.

7. allow access for your ip

8. when trying to access the site, type your ec2 ip address + port +/warprojectname/ + desinated start path

result : 

source : http://linuxcommand.org/lc3_writing_shell_scripts.php

Writing shell scripts

a shell script is file containing a series of commands. The shell reads this file and carries out the commands as though they have been entered directly on the command line. 

a shell script is a file that contains ascii text.

to create a shell script, you use a text editor. 

Use vi to use text editor, make sure to designate a folder name after typing the vi command 

#!/bin/bash

# My first script

echo "Hello World!"

And then… set permission as it follows, 

Chmod 755 hello_world

You could ./hello_world, but setting a path where all the files are stored in would be much more easily accessible. For example, all the commands are stored at $PATH. You could add your own path directory by the following

Export PATH=$PATH:directory

Now just typing hello_world would run your script.

A. Editing the scripts you already have

there are two kinds of shell session.

a login shell session is one that prompts for username and password.

a non-login shell session typically occurs for gui. 

~/.bashrc = a user's personal start up file. could make your own alias scripts here and you can use the commands regularly.

access the .bashrc file by: 

vi .bashrc

and add the following 

today() {

  echo -n "Today's date is: "

  date + "%A, %B %-d, %Y"

}

and restart your terminal to take effect and type today will output :

B. Here Scripts

Create a HTML using script

and then run:

sysinfo_page > sysinfo_page.html

C. Variables

How to create variables : 

variables can be declared on top of shell script as global variables and be used be adding $variablename

variablename="your text here"

there should be no spaces!

variable that comes with the system are called environment variables. environment variables can be checked by typing printenv.

by convention, environment variables are uppercase

D. Command Substitution and Constants

$() tells the shell to substitute the results of the enclosed command. 

There is an alternate syntax for $(), which is backticks ``. however ``backticks are older form and for readability, $() is much more prefered.

right_now=$(date +"%x %r %Z")

this is also possible

D.Shell Functions

For maintains and readability, it is often useful to break a single, large task into a series of smaller tasks.

Process of identifying the top-level steps and developing increasingly detailed views of those steps is called top-down design. 

When you are developing a program, it is is often a good practice to add a small amount of code, run the script, add some more code, run the script, and so on. This way, if you introduce a mistake into your code, it will be easier to find and correct.

stubbing = havent developed the function but instead of leaving it blank, could add a basic command like echo to run the script.

E. Flow Control - Part 1

The if statement has the following syntax:

if commands; then

commands

[elif commands; then

commands...]

[else

commands]

fi

**Commands issue a value to the system when they terminate, called an exit status. 

integer range from 0 to 255, 

An 8-bit unsigned integer has a range of 0 to 255, while an 8-bit signed integer has a range of -128 to 127 - both representing 256 distinct numbers.

as seen here, success command always outputs 0. however unsuccesful command results 2.

output nothing if it is false. just like all other programming languages, the basic set of rules are applied. 

id -u displays current users id. if your are a superuser the number will be 0.

>&2 is another I/O direction like cat << _EOF_. >&2 redirects the error message to standar error. this is used to separate error message and normal output. 

F. Stay out of trouble

when assigning value to a variable, empty value could be placed.

number=

but when including it to the if statement, you must include "" quotation marks around $number or empty value will be read as an equal sign, causing the script the not work properly.

add "-x" beginning of your script file to see your script run on terminal. 

G. Keyboard Input and Arithmetic

read command takes input from keyboard.

#!/bin/bash

echo -n "Enter some text > "

read text

echo "You entered: $text"

H. Flow Control - Part 2

The case command has the following form:

case word in

    patterns ) commands ;;

esac

looping

#!/bin/bash

number=0

while [ "$number" -lt 10 ]; do

     echo "Number = $number"

     number=$((number + 1))

done

I. Positional Parameters

Linux command notes

Shell - a program that takes commands from keyboard and gives them to the operating system to perform.

Nowadays we have graphical user interfaces in addition to command line interfaces such as the shell. 

On most linux system a bash acts as the shell program. 

Terminal - a program that gets you interact with the shell. 

A. Navigation 

1. pwd - prints current directory
2. cd - changes directory
3. ls - list files and directories

B. Looking around

1. Ls - list files and directories

ls -l - list the files in the working directory in long format

ls -la - list all files including the hidden ones

1. Less - view text files

1. File - classify a file’s contents 

Most commands operate in this pattern:

command -options arguments

C. A guided tour

symbolic links allows for multiple version of the same directory. Use ln command 

D. Manipulating files

1. Cp - copy files and directories
2. Mv - move or rename files and directories
3. Rm - remove files and directories
4. Mkdir - create directories

http://linuxcommand.org/lc3_lts0050.php

E. Working with commands

1. Type - display information about command type
2. Which - locate a command
3. Help - display reference page for shell builtin 
4. Man - display an on-line command reference

Commands can be one of 4 different kinds:

1. An executable program like all those files we saw in /usr/bin. Within this category, programs can be compiled binaries such as programs written in C and C++, or programs written in scripting languages such as the shell, Perl, Python, Ruby, etc.
2. A command built into the shell itself. bash provides a number of commands internally called shell builtins. The cd command, for example, is a shell builtin.
3. A shell function. These are miniature shell scripts incorporated into the environment. We will cover configuring the environment and writing shell functions in later lessons, but for now, just be aware that they exist.
4. An alias. Commands that you can define yourselves, built from other commands. This will be covered in a later lesson.

F. I/O redirection

most command line programs that display their results do so by sending their results to a facility called standards output. 

“>” character is used to send the output to a designated file 

“>>” character is used to append the output, single “>” overwrites the previous data of the file. 

$((arithmetic expression))

ex. Echo $(($((5 ** 2))* 3)) or 

$(((5 ** 2) * 3))

Brace Expression

mkdir {2007..2009}-0{1..9} {2007..2009}-{10..12}

$ echo a{A{1,2},B{3,4}}b

aA1b aA2b aB3b aB4b

G. Permissions

computing systems can have not only multitasking but also multi-user. Before computers were personal, a typical university computer system consisted of a large mainframe computer and terminals were located throughout the campus. 

1. Chmod - modify file accès rights

when ls -l is typed, -rwxrwxrwx type format may appear. The first case is displayed as - or d, - for file d for directory. there are three sections divided by three letters, each part in sequential order representing owner, group owner, and other users. 

chmod ### file/directory will modify the access rights. 

the numbers are represented as binary. for rwx, it will be 111 = 7. So if you want to grant all access to all users, which is not recommended, you have to type 777.

2. Su - temporarily become the superuser

you can become the superuser by typing the command su. Typing exit will end your superuser session. 

on apple though, su is disabled by default, I have enabled the su command using the taewon default password. 

3. Sudo - temporarily become the superuser

4. Chown - change file ownership

5. Chgrp - change a file’s group ownership

H. Job Control

**cannot perform this on Mac OS, have to get back to it once I install linux os**

a single processor computer can only execute one process t a time but the linux kernel manages to give each process its turn so it makes it look like it is running simultaneously. 

1. Ps - list the processes running on the system

2. Kill - send a signal to one or more processes (usually to kill a process)

3. Jobs - an alternate way of listing your own processes

4. Bg - put a process in the background

5. Fg - put a process in the foreground