Tutorial by Examples: r

{ "some_string": null, "ather_string": "something" } If we will use this way: JSONObject json = new JSONObject(jsonStr); String someString = json.optString("some_string"); We will have output: someString = "null"; So we need to...

Detailed instructions on getting braintree set up or installed.

A VectorDrawable should consist of at least one <path> tag defining a shape <vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="24dp" android:height="24dp" android:viewportWidth="24.0" android:viewpor...

A <group> tag allows the scaling, rotation, and position of one or more elements of a VectorDrawable to be adjusted: <vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="24dp" android:height="24dp" android:viewportWidth="24...

An AnimatedVectorDrawable requires at least 3 components: A VectorDrawable which will be manipulated An objectAnimator which defines what property to change and how The AnimatedVectorDrawable itself which connects the objectAnimator to the VectorDrawable to create the animation The following...

In AS3, display assets are not visible until they are added to the Display List. The AIR/Flash runtime has a hierarchical display structure (parent child relationship where children can have their own children), with the stage being the top level parent. To add something to the display list, you u...

The s interpolator allows the usage of variables within a string. val name = "Brian" println(s"Hello $name") prints "Hello Brian" to the console when ran.

Add an accessory view above the keyboard. This is commonly used for adding next/previous buttons, or additional buttons like Done/Submit (especially for the number/phone/decimal pad keyboard types which don't have a built-in return key). Swift let textField = UITextField() // initialized however ...

Given the following CSV file: Id,Name 1,"Joel" 2,"Adam" 3,"Ryan" 4,"Matt" You can read the data with the following script: #r "FSharp.Data.dll" open FSharp.Data type PeopleDB = CsvProvider<"people.csv"> let people = Pe...

Create Subtree Add a new remote called plugin pointing to the plugin's repository: git remote add plugin https://path.to/remotes/plugin.git Then Create a subtree specifying the new folder prefix plugins/demo. plugin is the remote name, and master refers to the master branch on the subtree's rep...

String concatenation can be performed using the + operator. For example: String s1 = "a"; String s2 = "b"; String s3 = "c"; String s = s1 + s2 + s3; // abc Normally a compiler implementation will perform the above concatenation using methods involving a StringBui...

0.18.0 Prior to 0.18.0 you can create ranges like this: > range = [1..5] [1,2,3,4,5] : List number > > negative = [-5..3] [-5,-4,-3,-2,-1,0,1,2,3] : List number 0.18.0 In 0.18.0 The [1..5] syntax has been removed. > range = List.range 1 5 [1,2,3,4,5] : List number > &g...

> listOfNumbers = [1,4,99] [1,4,99] : List number > > listOfStrings = ["Hello","World"] ["Hello","World"] : List String > > emptyList = [] -- can be anything, we don't know yet [] : List a > Under the hood, List (linked list) is ...

List.map : (a -> b) -> List a -> List b is a higher-order function that applies a one-parameter function to each element of a list, returning a new list with the modified values. import String ourList : List String ourList = ["wubba", "lubba", "dub",...

List.filter : (a -> Bool) -> List a -> List a is a higher-order function which takes a one-parameter function from any value to a boolean, and applies that function to every element of a given list, keeping only those elements for which the function returns True on. The function that List.f...

def multiply(factor: Int)(numberToBeMultiplied: Int): Int = factor * numberToBeMultiplied val multiplyBy3 = multiply(3)_ // resulting function signature Int => Int val multiplyBy10 = multiply(10)_ // resulting function signature Int => Int val sixFromCurriedCall = multiplyBy3(2) //6...

def numberOrCharacterSwitch(toggleNumber: Boolean)(number: Int)(character: Char): String = if (toggleNumber) number.toString else character.toString // need to explicitly specify the type of the parameter to be curried // resulting function signature Boolean => String val switchBetween3A...

def minus(left: Int, right: Int) = left - right val numberMinus5 = minus(_: Int, 5) val fiveMinusNumber = minus(5, _: Int) numberMinus5(7) // 2 fiveMinusNumber(7) // -2

To create a collection of n copies of some object x, use the fill method. This example creates a List, but this can work with other collections for which fill makes sense: // List.fill(n)(x) scala > List.fill(3)("Hello World") res0: List[String] = List(Hello World, Hello World, Hello...

For...Next loop is used for repeating the same action for a finite number of times. The statements inside the following loop will be executed 11 times. The first time, i will have the value 0, the second time it will have the value 1, the last time it will have the value 10. For i As Integer = 0 To...