// null is returned if none of the components in this application has the focus Component compFocusOwner = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner(); // null is returned if none of the windows in this application has the f…

Normally, a keystroke registered to a component is activated when the component has the focus. This type of activation condition is called WHEN_FOCUSED. It is possible to specify that a keystroke be activated if any component (including itself) in th…

Introduction about React component lifecycle. 1 Lifecycle A React component in browser can be any of the following three statuses: mounted, update and unmounted. So React component lifecycle can be divided into three phases according to these statuse…

Version 3, 29 June 2007       Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>   Everyone is permitted to copy and distribute verbatim copies   of this license document, but changing it is not allowed.       Preamble       The GNU…

A list of the standard attributes that you can use in themes can be found at R.styleable.Theme. Constants AbsListView_cacheColorHint Indicates that this list will always be drawn on top of solid, single-color opaque background. AbsListView_choiceMode…

消息,就是指Windows发出的一个通知,告诉应用程序某个事情发生了.例如,单击鼠标.改变窗口尺寸.按下键盘上的一个键都会使Windows发送一个消息给应用程序.消息本身是作为一个记录传递给应用程序的,这个记录中包含了消息的类型以及其他信息.例如,对于单击鼠标所产生的消息来说,这个记录中包含了单击鼠标时的坐标.这个记录类型叫做TMsg, 它在Windows单元中是这样声明的:typeTMsg = packed recordhwnd: HWND; / /窗口句柄message: UINT; / /…

In This Document Section 1: Overview Section 2: Pre-Upgrade Steps Section 3: Upgrade and Configuration Section 4: Post-installation Steps Section 5: Known Issues Section 6: Appendices This document covers the procedure to upgrade the version of the J…

这些CM消息,居然在Delphi的帮助里是没有任何说明的,真是昏倒.意外在高手的书里找到了所有说明,说明如下: Message Constant Value Description cm_Base $B000 Base constant used by all other component messages.cm_Activate cm_Base + 0; Specific to forms. Sent when form is first displayed and whenever foc…

装饰模式(Decorator Pattern): 动态地给一个对象增加一些额外的职责,就增加对象功能来说,装饰模式比生成子类实现更为灵活. 模式角色与结构: 示例代码: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace CSharp.DesignPattern.DecoratorPattern { class Program { static void M…

虽然目前房价依旧很高,就连我所在的成都郊区(非中心城区)的房价均价都早已破万,但却还是阻挡不了大家对新房的渴望和买房的热情.如果大家买的是清水房,那么无疑还有一项艰巨的任务在等着大家,那就是装修.对新房的装修并没有改变房屋用于居住的本质,但它可以让房子变得更加漂亮和温馨以及更加实用.在软件设计中,也有一种类似于新房装修的技术可以对已有的功能进行扩展使之更加符合用户需求,从而使得对象具有更加强大的功能,这便是本次即将介绍的装饰模式. 装饰模式(Decorator) 学习难度:★★★☆☆ 使用频率:…