Tutorial by Examples: u

Optional Parameters In TypeScript, every parameter is assumed to be required by the function. You can add a ? at the end of a parameter name to set it as optional. For example, the lastName parameter of this function is optional: function buildName(firstName: string, lastName?: string) { // ...

In themes.xml: <style name="AppTheme" parent="Theme.AppCompat"> <!-- Theme attributes here --> </style> In AndroidManifest.xml: <application android:icon="@mipmap/ic_launcher" android:label="@string/app_name" andr...

In themes.xml: <style name="MyActivityTheme" parent="Theme.AppCompat"> <!-- Theme attributes here --> </style> In AndroidManifest.xml: <application android:icon="@mipmap/ic_launcher" android:label="@string/app_name" ...

XML elements often nest, have data in attributes and/or as character data. The way to capture this data is by using ,attr and ,chardata respectively for those cases. var doc = ` <parent> <child1 attr1="attribute one"/> <child2>and some cdata</child2> </p...

Pointer Methods Pointer methods can be called even if the variable is itself not a pointer. According to the Go Spec, . . . a reference to a non-interface method with a pointer receiver using an addressable value will automatically take the address of that value: t.Mp is equivalent to (&t)....

Channels are often used to implement timeouts. func main() { // Create a buffered channel to prevent a goroutine leak. The buffer // ensures that the goroutine below can eventually terminate, even if // the timeout is met. Without the buffer, the send on the channel // blocks fo...

Using the Android API 23 or higher, very often such situation can be seen: This situation is caused by the structural change of the Android API regarding getting the resources. Now the function: public int getColor(@ColorRes int id, @Nullable Theme theme) throws NotFoundException should ...

package main import ( "log" "sync" "time" ) func main() { // The WaitGroup lets the main goroutine wait for all other goroutines // to terminate. However, this is no implicit in Go. The WaitGroup must // be explicitely incremented pr...

package main import ( "fmt" "time" ) // The pinger prints a ping and waits for a pong func pinger(pinger <-chan int, ponger chan<- int) { for { <-pinger fmt.Println("ping") time.Sleep(time.Second) ponge...

/** * Created by Alex Sullivan on 7/21/16. */ public class Foo implements Parcelable { private final int myFirstVariable; private final String mySecondVariable; private final long myThirdVariable; public Foo(int myFirstVariable, String mySecondVariable, long myThirdVariab...

This tutorial explains how to download Image using AsyncTask in Android. The example below download image while showing progress bar while during download. Understanding Android AsyncTask Async task enables you to implement MultiThreading without get Hands dirty into threads. AsyncTask enables pro...

Operators such as +, -, ?? are a kind of function named using symbols rather than letters. They are invoked differently from functions: Prefix: -x Infix: x + y Postfix: x++ You can read more about basic operators and advanced operators in The Swift Programming Language.

The MediaPlayer$prepare() is a blocking call and will freeze the UI till execution completes. To solve this problem, MediaPlayer$prepareAsync() can be used. mMediaPlayer = ... // Initialize it here mMediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener(){ @Override public ...

init Called synchronously after the instance has been initialized and prior to any initial data observation. created Called synchronously after the instance is created. This occurs prior to $el setup, but after data observation, computed properties, watch/event callbacks, and methods ha...

Since all lifecycle hooks in Vue.js are just functions, you can place any of them directly in the instance declaraction. //JS new Vue({ el: '#example', data: { ... }, methods: { ... }, //LIFECYCLE HOOK HANDLING created: function() { ...

import "reflect" value := reflect.ValueOf(4) // Interface returns an interface{}-typed value, which can be type-asserted value.Interface().(int) // 4 // Type gets the reflect.Type, which contains runtime type information about // this value value.Type().Name() // int value.SetInt(5)...

import "reflect" type S struct { A int b string } func (s *S) String() { return s.b } s := &S{ A: 5, b: "example", } indirect := reflect.ValueOf(s) // effectively a pointer to an S value := indirect.Elem() // this is addressable, since we've derefed a point...

import "reflect" // this is effectively a pointer dereference x := 5 ptr := reflect.ValueOf(&x) ptr.Type().Name() // *int ptr.Type().Kind() // reflect.Ptr ptr.Interface() // [pointer to x] ptr.Set(4) // panic value := ptr.Elem() // this is a deref value.Type().Name() // int...

Directives comes with the AngularJS library itself. A sample directive can be created as: angular.module('simpleDirective', []) .directive('helloData', function() { return { template: 'Hello, {{data}}' }; }); And can be used as: JS: angular.module('app', ['simpleDirective']) .con...

In go it can sometimes be useful to know which underlying type you have been passed. This can be done with a type switch. This assumes we have two structs: type Rembrandt struct{} func (r Rembrandt) Paint() {} type Picasso struct{} func (r Picasso) Paint() {} That implement the Painter ...