Tutorial by Examples: nf

By default error message appears below textbox in <div class="help-block"></div> on keyUp or after pressing submit button if any validation constraints aren't met. Sometimes we want a message on submit only i.e. no validation at onKeyup event. Let's check yii2/widgets/ActiveF...

Running the latest Liferay CE is straightforward: Go to https://www.liferay.com/downloads. Choose a bundle among the ones listed. For beginners, the Tomcat bundle is a good choice. Click in "Download." Unzip the download package whenever you find fit. The unzipped directory will...

foo.h #ifndef FOO_DOT_H /* This is an "include guard" */ #define FOO_DOT_H /* prevents the file from being included twice. */ /* Including a header file twice causes all kinds */ /* of interesting problems.*/ /** * This is a functi...

To use Vagrant on Windows platform you need to install virtualization software and an ssh command-line tool first. This example will use freeware VirtualBox and Cygwin. Install VirtualBox Download the latest VirtualBox version from the official download page and run the downloaded file. Note that ...

A subquery in a FROM clause acts similarly to a temporary table that is generated during the execution of a query and lost afterwards. SELECT Managers.Id, Employees.Salary FROM ( SELECT Id FROM Employees WHERE ManagerId IS NULL ) AS Managers JOIN Employees ON Managers.Id = Employees.Id ...

Strings in JavaScript can be enclosed in Single quotes 'hello', Double quotes "Hello" and (from ES2015, ES6) in Template Literals (backticks) `hello`. var hello = "Hello"; var world = 'world'; var helloW = `Hello World`; // ES2015 / ES6 Strings can be created...

Write the following command in your terminal: adb shell getprop This will print all available information in the form of key/value pairs. You can just read specific information by appending the name of a specific key to the command. For example: adb shell getprop ro.product.model Here are a...

Configure your project-level build.gradle to include the android-apt plugin: buildscript { repositories { mavenCentral() } dependencies { classpath 'com.jakewharton:butterknife-gradle-plugin:8.5.1' } } Then, apply the android-apt plugin in your module-level build...

Android supports several configuration qualifiers that allow you to control how the system selects your alternative resources based on the characteristics of the current device screen. A configuration qualifier is a string that you can append to a resource directory in your Android project and speci...

To remove existing column name from users table, run the command: rails generate migration RemoveNameFromUsers name:string This will generate the following migration: class RemoveNameFromUsers < ActiveRecord::Migration[5.0] def change remove_column :users, :name, :string end end ...

If you want to add custom.js script that is located in the js/ folder of your theme, you'll need to enqueue it. In functions.php add <?php add_action( 'after_setup_theme', 'yourtheme_theme_setup' ); if ( ! function_exists( 'yourtheme_theme_setup' ) ) { function yourtheme_theme_setup()...

Migrations in a Laravel 5 application live in the database/migrations directory. Their filenames conform to a particular format: <year>_<month>_<day>_<hour><minute><second>_<name>.php One migration file should represent a schema update to solve a particu...

Creating a new migration file with the correct filename every time you need to change your schema would be a chore. Thankfully, Laravel's artisan command can generate the migration for you: php artisan make:migration add_last_logged_in_to_users_table You can also use the --table and --create fla...

For setting some zoom level, let say we want to zoom user's location with user location as center and 2km of area as radius. Then, we use following code MKUserLocation *userLocation = _mapView.userLocation; MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance (userLocation.location.coord...

function Invoke-MyCmdlet { [CmdletBinding(SupportsShouldProcess = $true)] param() # ... }

C++11 One of constraining function is to use trailing decltype to specify the return type: namespace details { using std::to_string; // this one is constrained on being able to call to_string(T) template <class T> auto convert_to_string(T const& val, int ) ->...

Parentheses are used to enclose the arguments of function calls. Using them for procedure calls can cause unexpected problems. Because they can introduce bugs, both at run-time by passing a possibly unintended value to the procedure, and at compile-time by simply being invalid syntax. Run-time Re...

If a case class has exactly two values, its extractor can be used in infix notation. case class Pair(a: String, b: String) val p: Pair = Pair("hello", "world") val x Pair y = p //x: String = hello //y: String = world Any extractor that returns a 2-tuple can work this way....

In Rails, you find yourself looking at controllers, views, and models for your database. To reduce the need for heavy configuration, Rails implements rules to ease up working with the application. You may define your own rules but for the beginning (and for later on) it's a good idea to stick to co...

Now that the router is configured and our app knows how to handle the routes, we need to show the actual components that we configured. To do so, configure your HTML template/file for your top-level (app) component like so: //app.ts import {Component} from '@angular/core'; import {Router, ROUT...