interface

Empty interface{} in function type

由 那年仲夏 提交于 2020-03-17 06:05:30
问题 An object of any type can be assigned to an empty interface. For example, we have the following function func Println(i interface{} ) { fmt.Println(i) } We can call it by Println(3) Println(1.5) Println("Hello") But I can't achieve the same thing for function type func Map(fn func( interface{} )) { ...... } I cannot call this with Map( func( i int) {......} ) because the type func(int) is different from the type func( interface{} ) . But when I define func( interface{} ) , I really mean any

Empty interface{} in function type

由 三世轮回 提交于 2020-03-17 06:04:52
问题 An object of any type can be assigned to an empty interface. For example, we have the following function func Println(i interface{} ) { fmt.Println(i) } We can call it by Println(3) Println(1.5) Println("Hello") But I can't achieve the same thing for function type func Map(fn func( interface{} )) { ...... } I cannot call this with Map( func( i int) {......} ) because the type func(int) is different from the type func( interface{} ) . But when I define func( interface{} ) , I really mean any

Cast object to interface in TypeScript

由 别等时光非礼了梦想. 提交于 2020-03-12 11:40:06
问题 I'm trying to make a cast in my code from the body of a request in express (using body-parser middleware) to an interface, but it's not working. It's possible to do this? This is my interface: export interface IToDoDto { description: string; status: boolean; }; This is the code where I'm trying to do the cast: @Post() addToDo(@Response() res, @Request() req) { const toDo: IToDoDto = <IToDoDto> req.body; this.toDoService.addToDo(toDo); return res.status(HttpStatus.CREATED).end(); } And finally

reusable UI in android app

由 孤街醉人 提交于 2020-03-05 04:08:43
问题 I am working on android app where I am thinking to develop reusable UI interface. How it can be developed and included in my .xml's Here I want to develop a progress bar with my image and it will be display on some .xml's. Please provide any code help. I am a new in this field. 回答1: you can use <Include> xml tag within your layout xml, read this :) http://developer.android.com/resources/articles/layout-tricks-merge.html 回答2: I think you need to use styles and themes. Check this out. 回答3: You

Generate a typescript interface that references itself

由 可紊 提交于 2020-03-05 04:08:06
问题 EDIT: I have rewritten this question to be much clearer. I am trying to programmatically infer an interface which references itself. I am writing some code which can encode a recursive structure in binary. For example: const myTreeEncoder = Struct(Self => ({ name: Str, children: List(Self) }); This can encode structures like this from binary and back: const someUint8Array = myTreeEncoder.encode({ name: 'parent', children: [{ name: 'child', children: [] }] }); The problem is, how can the

abstract class和interface的使用场景分别是什么？

由 余生颓废 提交于 2020-03-04 10:15:16
abstract class 和 interface 是 Java 语言中对于抽象类定义进行支持的两种机制，正是由于这两种机制的存在，才赋予了 Java 强大的面向对象能力。 abstract class 和 interface 之间在对于抽象类定义的支持方面具有很大的相似性，甚至可以相互替换，因此很多开发者在进行抽象类定义时对于 abstract class 和 interface 的选择显得比较随意。其实，两者之间还是有很大区别的，对于它们的选择甚至反映出对于问题领域本质的理解、对于设计意图的理解是否正确、合理。我认为正确运用好抽象类和接口，可以优化软件结构的设计，对软件的扩展、维护带来很大的便利。本文将对它们之间的区别进行一番剖析，试图给开发者提供一个在二者之间进行选择的依据。 首先来理解一下抽象类。在面向对象的概念中，我们知道所有的对象都是通过类来描绘的，如果一个类中没有包含足够的信息来描绘一个具体的对象，这样的类就是抽象类。抽象类往往用来表征我们在对问题领域进行分析、设计中得出的抽象概念，是对一系列看上去不同，但是本质上相同的具体概念的抽象。比如我们 xpads 项目中的交易类就可以理解为一个抽象类，即期交易、远期交易、掉期交易等都是继承交易类的具体类。即期交易、远期交易、掉期交易这些具体概念是实际存在的，而交易这个概念在问题领域中是不存在的，可以理解为一个抽象概念

wifi测试相关（iwconfig，WPA Supplicant用法）

由 扶醉桌前 提交于 2020-03-01 09:58:50
iwconfig用法 1.打开无线网卡电源 iwconfig wlan0 txpower no 2.列出区域内的无线网络 iwconfig wlan0 scan 3.假设要连接到网络myhome（即essid为myhome的网络），那么输入命令 iwconfig wlan0 essid "myhome" 如果网络是加密的，密码是0123456789，那么就输入命令 iwconfig wlan0 essid "myhome" key 0123-4567-89 4 如果正常的话，输入 iwconfig wlan0 就可以看到连接正常的各项参数了。 5.启动无线网卡 ifconfig wlan0 up 6.如果是用DHCP获取IP的，那么用dhclient或dhcpcd获取ip dhclient wlan0 或 dhcpcd wlan0 7.现在无线网卡应该可以正常使用了。 WPA Supplicant WPA Supplicant 工具包可以让您连接到那些使用WPA的AP。因为还只是beta版，所以它的配置方法仍会常常变化——尽管如此，在大部分情况下它已经能很好的工作。 代码 2.1: 安装wpa_supplicant emerge net-wireless/wpa_supplicant 重要: 要让 wpa_supplicant 正常工作，您必须在内核中打开 CONFIG

Can a same method exist in a class twice, through Inheritance and interfaces?

由 大兔子大兔子 提交于 2020-02-24 17:35:47
问题 Here is the scenario:- class Canine{ public void roam(){ System.out.println("Canine-Roam"); } } public interface Pet{ public abstract void roam(); } class Dog extends Canine implements Pet{ public void roam(){ System.out.println("Dog Roam"); } public static void main(String [] args){ Dog adog = new Dog(); adog.roam(); } } I am aware that JVM must not have any confusion in choosing which method to run, that means, which method gets over-ridden. But I am confused anyway. Why does this program

Where did the Text Selection API go?

由 时间秒杀一切 提交于 2020-02-24 17:31:46
问题 Two years ago the HTML5 standard dropped the chapter "Text Selection API" which contained a specification of the Selection interface: [Stringifies] interface Selection { readonly attribute Node anchorNode; readonly attribute long anchorOffset; readonly attribute Node focusNode; readonly attribute long focusOffset; readonly attribute boolean isCollapsed; void collapse(in Node parentNode, in long offset); void collapseToStart(); void collapseToEnd(); void selectAllChildren(in Node parentNode);

Where did the Text Selection API go?

由 两盒软妹~` 提交于 2020-02-24 17:31:27
问题 Two years ago the HTML5 standard dropped the chapter "Text Selection API" which contained a specification of the Selection interface: [Stringifies] interface Selection { readonly attribute Node anchorNode; readonly attribute long anchorOffset; readonly attribute Node focusNode; readonly attribute long focusOffset; readonly attribute boolean isCollapsed; void collapse(in Node parentNode, in long offset); void collapseToStart(); void collapseToEnd(); void selectAllChildren(in Node parentNode);
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