Tutorial by Examples: f

Log for a range of lines within a file

$ git log -L 1,20:index.html commit 6a57fde739de66293231f6204cbd8b2feca3a869 Author: John Doe <[email protected]> Date: Tue Mar 22 16:33:42 2016 -0500 commit message diff --git a/index.html b/index.html --- a/index.html +++ b/index.html @@ -1,17 +1,20 @@ <!DOCTYPE HTML> ...

Git • Browsing the history

Changing the author of commits

You can use an environment filter to change the author of commits. Just modify and export $GIT_AUTHOR_NAME in the script to change who authored the commit. Create a file filter.sh with contents like so: if [ "$GIT_AUTHOR_NAME" = "Author to Change From" ] then export GIT_A...

Git • Rewriting history with filter-branch

Taking a screenshot and video (for kitkat only) from a device display

Screen shot: Option 1 (pure adb) The shell adb command allows us to execute commands using a device's built-in shell. The screencap shell command captures the content currently visible on a device and saves it into a given image file, e.g. /sdcard/screen.png: adb shell screencap /sdcard/screen.png...

Android • ADB (Android Debug Bridge)

Forbid null values

To forbid null values in your table columns, add the :null parameter to your migration, like this: class AddPriceToProducts < ActiveRecord::Migration def change add_column :products, :float, null: false end end

Ruby on Rails • ActiveRecord Migrations

Show addresses on a google map in the profile view

On the profile view, show the profile fields of a user or group in a list as well as the address fields on a google map. - # app/views/profiles/show.html.haml %h1 Contact Information .profile_fields = render @profile_fields .google_map{data: address_fields: @address_fields.to_json } The ap...

Ruby on Rails • Using GoogleMaps with Rails

Initialize the map using a coffee script class.

Provided an App.GoogleMap coffee script class, the google map can be initialized like this: # app/assets/javascripts/google_maps.js.coffee # ... class App.GoogleMap map_div: {} map: {} constructor: (map_div)-> @map_div = map_div @init_map() @reference_the_map_as_dat...

Ruby on Rails • Using GoogleMaps with Rails

Initialize the map markers using a coffee script class

Provided an App.GoogleMap coffee script class and the marker information being stored in the data-address-fields attribute of the .google_map div, the map markers can be initialized on the map like this: # app/assets/javascripts/google_maps.js.coffee # ... class App.GoogleMap # ... markers:...

Ruby on Rails • Using GoogleMaps with Rails

Auto-zoom a map using a coffee script class

Provided an App.GoogleMap coffee script class with the google.maps.Map stored as @map and the google.maps.Markers stored as @markers, the map can be auto-zoomed, i.e. adjusted that all markers are visible, like this: on the map like this: # app/assets/javascripts/google_maps.js.coffee # ... cla...

Ruby on Rails • Using GoogleMaps with Rails

Setting Different priorities in notification

NotificationCompat.Builder mBuilder = (NotificationCompat.Builder) new NotificationCompat.Builder(context) .setSmallIcon(R.drawable.some_small_icon) .setContentTitle("Title") .setContentText("This is a test notification with MAX priority")...

Android • Notifications

Get locale from HTTP request

Sometimes it can be useful to set your application locale based upon the request IP. You can easily achieve this using Geocoder. Among the many things Geocoder does, it can also tell the location of a request. First, add Geocoder to your Gemfile # Gemfile gem 'geocoder' Geocoder adds location...

Ruby on Rails • I18n - Internationalization

Get first and last record

Rails have very easy way to get first and last record from database. To get the first record from users table we need to type following command: User.first It will generate following sql query: SELECT `users`.* FROM `users` ORDER BY `users`.`id` ASC LIMIT 1 And will return following recor...

Ruby on Rails • ActiveRecord Query Interface

Cloning by implementing Clonable interface

Cloning an object by implementing the Cloneable interface. public class Sheep implements Cloneable { private String name; private int weight; public Sheep(String name, int weight) { this.name = name; this.weight = weight; } @Override public Ob...

Java Language • Object Cloning

Single file upload using Carrierwave

Start using File Uploads in Rails is quite simple, first thing you have to do is to choice plugin for managing uploads. The most common onces are Carrierwave and Paperclip. Both are similar in functionality and rich in documentation on Let's have an look on example with simple avatar upload image w...

Ruby on Rails • File Uploads

Fragment caching

Rails.cache, provided by ActiveSupport, can be used to cache any serializable Ruby object across requests. To fetch a value from the cache for a given key, use cache.read: Rails.cache.read('city') # => nil Use cache.write to write a value to the cache: Rails.cache.write('city', 'Duckburgh'...

Ruby on Rails • Caching

Fat Model, Skinny Controller

“Fat Model, Skinny Controller” refers to how the M and C parts of MVC ideally work together. Namely, any non-response-related logic should go in the model, ideally in a nice, testable method. Meanwhile, the “skinny” controller is simply a nice interface between the view and model. In practice, this...

Ruby on Rails • Rails Best Practices

Define String Plurals

To differentiate between plural and singular strings, you can define a plural in your strings.xml file and list the different quantities, as shown in the example below: <?xml version="1.0" encoding="utf-8"?> <resources> <plurals name="hello_people&quo...

Android • Resources

Insert line after first match

Given a file file.txt with the following content: line 1 line 2 line 3 You can add a new line after first matching line with the a command. For portable use the a command must be followed immediately by an escaped newline, with the text-to-append on its own line or lines. sed ' /line 2/a\ ...

sed • Append command

Date Picker within DialogFragment

xml of the Dialog: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="mat...

Android • Dialog

Loading Image from external Storage

String filename = "image.png"; String imagePath = getExternalFilesDir() + "/" + filename; Picasso.with(context) .load(new File(imagePath)) .into(imageView);

Android • Picasso

Filters

Filters are methods that are run "before", "after" or "around" a controller action. They are inherited, so if you set any in your ApplicationController they will be run for every request your application receives. Before Filter Before filters are executed before the c...

Ruby on Rails • ActionController