Tutorial by Examples: v

adb shell am start -n com.android.settings/.DevelopmentSettings Will navigate your device/emulator to the Developer Options section.

Swift classes supports having multiple ways of being initialized. Following Apple's specs this 3 rules must be respected: A designated initializer must call a designated initializer from its immediate superclass. A convenience initializer must call another initializer from the same class. A ...

std::function type erases down to a few operations. One of the things it requires is that the stored value be copyable. This causes problems in a few contexts, like lambdas storing unique ptrs. If you are using the std::function in a context where copying doesn't matter, like a thread pool where ...

Pygame will register all events from the user into an event queue which can be received with the code pygame.event.get(). Every element in this queue is an Event object and they'll all have the attribute type, which is an integer representing what kind of event it is. In the pygame module there are ...

To determine the version of Azure PowerShell that you have installed, run the following: Get-Module -ListAvailable -Name Azure -Refresh This command returns the installed version even when you haven't loaded the Azure PowerShell module in your current PowerShell session.

If a java library contains interfaces that should be implemented by the user (e.g. click listeners like View.IOnClickListener or callbacks), the implementing class has to inherit -- directly or indirectly -- from Java.Lang.Object or Java.Lang.Throwable. This is a common error, because the packaging ...

Step 1. In your host machine (Windows/Linux/OSX), create an empty dir my_project. Step 2. Create a file named Vagrantfile with this: Vagrant.configure("2") do |config| config.vm.box = "gbarbieru/xenial" #An Ubuntu 16.04 based image config.vm.hostname = "my_project&...

class User { String name int age } def users = [ new User(name: "Bob", age: 20), new User(name: "Tom", age: 50), new User(name: "Bill", age: 45) ] def null_value = users.find { it.age > 100 } // no over-100 found. Null null_value?.name?....

for numbers, a zero value evaluates to false, non zero to true int i = 0 ... if (i) print "some ${i}" else print "nothing" will print "nothing"

a string (including GStrings) evaluates to true if not null and not empty, false if null or empty def s = '' ... if (s) println 's is not empty' else println 's is empty' will print: 's is empty'

Collections and Maps evaluates to true if not null and not empty and false if null or empty /* an empty map example*/ def userInfo = [:] if (!userInfo) userInfo << ['user': 'Groot', 'species' : 'unknown' ] will add user: 'Groot' , species : 'unknown' as default userInfo since the u...

a null object reference evaluates to false, a non null reference to true, but for for strings, collections, iterators and enumerations it also takes into account the size. def m = null if (!m) println "empty" else println "${m}" will print "empty" de...

Sometimes it may be useful to have a specific asBoolean definition in your own program for some kind of objects. /** an oversimplified robot controller */ class RunController { def complexCondition int position = 0 def asBoolean() { return complexCondition(this...

Of course, the best way to detect mobile is for the hardware to notify you directly. Cordova PhoneGap exposes a 'deviceready' event, that you can add an event listener to. document.addEventListener('deviceready', function(){ Session.set('deviceready', true); }, false);

If the Node event loop acts like a bicycle chain, the server-side collection observer is like a derailleur. It's a gearing mechanism that is going to sit on the data collection as the data comes in. It can be very performant, as all race bicycles have derailleurs. But it's also a source for breaking...

Inspecting an Object You can find the public methods an object can respond to using either the methods or public_methods methods, which return an array of symbols: class Foo def bar; 42; end end f = Foo.new def f.yay; 17; end p f.methods.sort #=> [:!, :!=, :!~, :<=>, :==, :===, :=...

It is possible to query an object about its instance variables using instance_variables, instance_variable_defined?, and instance_variable_get, and modify them using instance_variable_set and remove_instance_variable: class Foo attr_reader :bar def initialize @bar = 42 end end f = F...

The Kernel exposes methods for getting the list of global_variables and local_variables: cats = 42 $demo = "in progress" p global_variables.sort #=> [:$!, :$", :$$, :$&, :$', :$*, :$+, :$,, :$-0, :$-F, :$-I, :$-K, :$-W, :$-a, #=> :$-d, :$-i, :$-l, :$-p, :$-v, :$-w, :$...

Classes and modules have the same methods for introspecting instance variables as any other object. Class and modules also have similar methods for querying the class variables (@@these_things): p Module.methods.grep(/class_variable/) #=> [:class_variables, :class_variable_get, :remove_class_va...

It is a common practice to set application variables to an object scope. This keeps them easy to identify and distinguish from variables in other scopes. The Variables scope in a CFC is private to the CFC. When you set variables in this scope, they cannot be seen by pages that invoke the CFC. <...