virtual

I want to override the behaviour of the ENTER key of the virtual keyboard so that: when there are more fields on the screen, it 'tabs' to the next field when it is the last field of the screen, it performs the default action of the screen I've been playing with the IME options and labels, but just don't get what I want. Anybody have any suggestions? Aak With help on another forum, I found the way to do it. To make it reusable, I have created my own super dialog class that contains 2 OnKeyListener objects and an abstract submit method: public abstract class MyAbstractDialog extends Dialog { /**

双链表 双链表的意义 单链表相对于顺序表，确实在某些场景下解决了一些重要的问题，例如在需要插入或者删除大量元素的时候，它并不需要像顺序表一样移动很多元素，只需要修改指针的指向就可以了， 其时间复杂度为 O(1) 但是这可是有前提的，那就是这一切都基于确定节点后 ，纯粹考虑删除和插入的情况下，但是如果我们仍未确定节点的位置，那么单链表就会出现一些问题了，例如我们来看一下 删除 这个操作 删除操作 单链表: 对应图中的节点，想要删除第2个节点 a1 只需要 将首元结点的指针指向到第三个节点的地址去 但是问题就在于我们如何得到待删除节点的前驱，也就是我们图中的首元结点，我们给出两种方法 A：定位待删除节点的同时，一直顺便保存当前节点的前驱 B：删除节点后，重新回到单链表表头，定位到其指定前驱 但是无论我们选择哪一种方法，指针的总移动数都会是 2n 次，而双链表却在这一类型问题上做出了很好的处理 双链表: 单链表中之所以出现问题，就是因为各个节点只有一个指向后继的指针域 next，只能向后移动查找，一旦我们想要查询前一节点，就变得很麻烦，所以双链表就在每个节点前面增加一个指向前驱的指针域 prior，这样我们就可以直接定位到我们的前一个节点了，这也就是双链表 注意：为了统一运算，避免特殊情况的出现，我们也常常在尾部设置一个 “尾部头结点” 其 next 指针域为空 线性表的抽象数据类型定义

Why it is recommended not to have data members in virtual base class? What about function members? If I have a task common to all derived classes is it OK for virtual base class to do the task or should the derived inherit from two classed - from virtual interface and plain base that do the task? Thanks. As a practice you should only use virtual inheritance to define interfaces as they are usually used with multiple inheritance to ensure that only one version of the class is present in the derived class. And pure interfaces are the safest form of multiple inheritance. Of course if you know

What is the reason for removing the ability to stop the propagation of methods virtuality? Let me be clearer: In C++, whether you write "virtual void foo()" or "void foo()" in the derived class, it will be virtual as long as in the base class, foo is declared virtual. This means that a call to foo() through a derived* pointer will result in a virtual table lookup (in case a derived2 function overrides foo), even if this behavior is not wanted by the programmer. Let me give you an example (that looks pretty blatant to me) of how it would be useful to stop virtuality propagation: template <class

When I try the open Virtual Device, I see the same error. What can I do? That error : Emulator: warning: host doesn't support requested feature: CPUID.80000001H:ECX.abm [bit 5] I can't fix my problem :/ I asked yesterday but anyone answer it :/ Note : Virtualization Technology is enabled and KVM is OK. This error is referring to CPU feature called LZCNT. It was introduced in Intel processors since Haswell (2013) and in AMD since 2007. So if your CPU is older or to any other reason does not support LZCNT - you will get this warning. You can check if your CPU support LZCNT instruction by

I am trying to write about 5 websites all on one Apache server which is all on one IP address. For example: /var/www/site1 /var/www/site2 /var/www/site3 /var/www/site4 /var/www/site5 However, if I create a link on site 2 just using, for example. /index.php, you would expect it to look in /var/www/site2/index.php... but it actually resolves to /var/www/index.php. Is there anyway of setting up Apache to know that the separate site folders need to behave and resolve to the separate folders? This is my sites-available file at the moment. A fairly default setup I believe: <VirtualHost *:80>

I have knowledge of java and have been learning c# for the last couple of days. Now I have come across the "virtual" keyword which, as suggested at this link , is used to allow the corresponding methods, properties etc. to be overriden in the subclasses. Now I think we can override methods even without using the "virtual" keyword. Then why it is necessary? You need the virtual keyword if you really want to override methods in sub classes. Otherwise the base implementation will be hidden by the new implementation, just as if you had declared it with the new keyword. Hiding the methods by

本文翻译自 Policies/Binary Compatibility Issues With C++ 二进制兼容的定义 如果程序从一个以前版本的库动态链接到新版本的库之后，能够继续正常运行，而不需要重新编译，那么我们就说这个库是二进制兼容的。 如果一个程序需要重新编译来运行一个新版本的库，但是不需要对程序的源代码进一步的修改，这个库就是源代码兼容的。 二进制兼容性可以节省很多麻烦。这使得为特定平台分发软件变得更加容易。如果不确保版本之间的二进制兼容性，人们将被迫提供静态链接的二进制文件。静态二进制文件不好，因为它们 浪费资源（尤其是内存） 不能让程序从库中错误修正或扩展中受益 如何确保二进制兼容 在确保二进制兼容的情况下，我们能做的操作： 增加非虚函数、signal/slots、构造函数 增加枚举到类中 在已经存在的枚举的最后添加枚举值 例外：如果这会导致编译器为枚举选择更大的底层类型，那么更改会导致二进制不兼容。需要注意的是，编译器有选择基础类型的余地，所以从 API 设计的角度来看，建议添加一个 Max 枚举，其中包含一个明确的最大值（=255 或 =1 << 15 等）来创建一个数字枚举数值的区间，使其无论如何能够保证适合所选择的底层类型。 重新实现在父非虚基类 (从当前类回溯第一个非虚基类）里定义的虚函数，但是这个不完全确保二进制兼容，所以尽量不要这么做 例外： C++