visibility

问题 I just want the #menu to fade when the scroll bar is moving to provide a less cluttered interface. Is there code that would allow this? I guess basically what I'm looking for is how to grab the scroll bar movement event. To slowly fade out the #menu after 1 seconds of scrolling and bring back the #menu after 2 second of scroll-bar inactivity. Thank you so much! 回答1: var $menu = $("#menu"); var opacity = $menu.css("opacity"); var scrollStopped; var fadeInCallback = function () { if (typeof

问题 I have a StackPanel which I want to make visible only when SomeTabControl.SelectedItem != null . How do I do this in WPF binding? 回答1: You can do it without a converter by using a style and trigger: <StackPanel> <StackPanel.Style> <Style TargetType="{x:Type StackPanel}"> <Setter Property="Visibility" Value="Visible" /> <Style.Triggers> <DataTrigger Binding="{Binding SelectedItem,ElementName=tabControl1}" Value="{x:Null}"> <Setter Property="Visibility" Value="Hidden" /> </DataTrigger> <Style

问题 How to hide a button, a label or a grid cell on iOS and show it on android, I have a xamarin.forms app (portable), I know that I have to use on platform but how to access the visibility of the controls. Thanks 回答1: // IOS, Android, WP SomeButton.IsVisible = Device.OnPlatform<bool>(false, true, true); Or if (Device.OS == TargetPlatform.Android) { SomeButton.IsVisible = true; } else ... 回答2: If you want to do it on XAML, in order to hide a view on a specific platform, you can use this: <Button>

问题 If I define a class with a private default constructor and a public constructor that has parameters, how can I access the private constructor? public class Bob { public String Surname { get; set; } private Bob() { } public Bob(string surname) { Surname = surname; } } I can access the private constructor via a static method on the class like this: public static Bob GetBob() { return new Bob(); } I thought that I could access the private constructor via an extension method, since (according to

问题 What's the best way to check if the view is visible on the window? I have a CustomView which is part of my SDK and anybody can add CustomView to their layouts. My CustomView is taking some actions when it is visible to the user periodically. So if view becomes invisible to the user then it needs to stop the timer and when it becomes visible again it should restart its course. But unfortunately there is no certain way of checking if my CustomView becomes visible or invisible to the user. There

问题 Now Eclipse Indigo SR1 with builtin Java 7 support is finally out since a week or two, I'm migrating my playground projects from Helios SR2 + JDK 1.6_23 to Indigo SR1 + JDK 1.7.0. After a full rebuild of all projects, only one class has failed to compile. It's the following class which compiles and runs perfectly fine on Java 1.6 (and 1.5): public abstract class Area<A extends Area<?>> implements Comparable<Area<?>> { private String name; private Area<?> parent; private Set<A> areas;

问题 This is a scaled down version of a problem I am facing with clang++ on Mac OS X. This was seriously edited to better reflect the genuine problem (the first attempt to describe the issue was not exhibiting the problem). The failure I have this big piece of software in C++ with a large set of symbols in the object files, so I'm using -fvisibility=hidden to keep my symbol tables small. It is well known that in such a case one must pay extra attention to the vtables, and I suppose I face this

问题 As is known guarant that if we have some object reference and this reference has final field - we will see all reachable fields from final field(at least when constructor was finished) example 1: class Foo{ private final Map map; Foo(){ map = new HashMap(); map.put(1,"object"); } public void bar(){ System.out.println(map.get(1)); } } As I undertand at this case we have guarantee that bar() method always output object because: 1. I listed full code of class Foo and map is final; 2. If some

问题 As is known guarant that if we have some object reference and this reference has final field - we will see all reachable fields from final field(at least when constructor was finished) example 1: class Foo{ private final Map map; Foo(){ map = new HashMap(); map.put(1,"object"); } public void bar(){ System.out.println(map.get(1)); } } As I undertand at this case we have guarantee that bar() method always output object because: 1. I listed full code of class Foo and map is final; 2. If some

问题 I recently discovered the linker option "-Bsymbolic-functions" in GNU ld: -Bsymbolic When creating a shared library, bind references to global symbols to the definition within the shared library, if any. Normally, it is possible for a program linked against a shared library to override the definition within the shared library. This option is only meaningful on ELF platforms which support shared libraries. -Bsymbolic-functions When creating a shared library, bind references to global function