visibility

问题 I am using Swing framework, and I have one question. The Address panel is dynamically added to the main frame. I want to call the visible(false) method from the main frame on the Address Panel. 回答1: What you need to do is store the JTextField as a private member of the AddressPanel . And, in AddressPanel , add a method called hideTextField() . Then, in that method call the setVisible(false) method on the private JTextField member. The code may look similar to the following: public class

问题 Here is the original code //@author Brian Goetz and Tim Peierls @ThreadSafe public class SafePoint { @GuardedBy("this") private int x, y; private SafePoint(int[] a) { this(a[0], a[1]); } public SafePoint(SafePoint p) { this(p.get()); } public SafePoint(int x, int y) { this.set(x, y); } public synchronized int[] get() { return new int[]{x, y}; } public synchronized void set(int x, int y) { this.x = x; this.y = y; } } Here it is fine that the private int x,y are not final because the set method

问题 Context: I'm trying to learn/practice TDD and decided I needed to create an immutable class. To test the 'immutability invariant' (can you say that?) I thought I would just call all the public methods in the class via reflection and then check that the class had not changed afterwards. That way I would be unlikely to break the invariant carelessly later on. This may or may not be practical/valid in itself but I thought it would also be an exercise in reflection for me. Strategies: Use

问题 I'm having an issue where by I'm using the "FindName()" method of the FrameworkElement object to search for a child control of that element. There's some interesting behavior that I've noticed and can't seem to figure out. If the user scrolls the browser window so that the control itself visibly is not shown anymore within the context of the window frame, then the "FindName()" does not return the element. However, if that control is visible within the window frame, it finds it fine. Is this a

问题 I know it's not a great idea to try and place properties in a category. Can I access a class' instance variables from within a category that extends it? Or is it necessary to expose an accessor on the class being extended? For example, let's say I have a class called "Person" and its implementation looks like this: #import "Person.h" @interface Person() { NSMutableArray *_friends; } @end @implementation Person - (instancetype)init { self = [super init]; if (self) { _friends = [NSMutableArray

问题 I checked the stackpanel class here http://msdn.microsoft.com/en-us/library/system.windows.controls.stackpanel.aspx and it has no click event. I'm working on a windows phone 8 app and I've got a textbox and some buttons on a stack panel. I want to include a feature where the stackpanel can be clicked then the visibility of the controls on it are set to collapsed, and then when clicked again they become visible. How do I do this? 回答1: You can solve this problem in a little tricky manner, if it

问题 I've a strange problem with binding a boolean property to a View's Visibility property. I have a 'main' View that contains a bunch of other Views as well as various other UIElements including Buttons, TextBoxes, Grids, StackPanels and some telerik controls. Some of the controls have their visibility bound to boolean properties on my ViewModel, such that when the property is positive they are shown, and when negative they are collapsed. <Border Visibility="{Binding IsSectionShown, Converter=

问题 I've created a report that has an image on the left that is conditionally visible based on a parameter that's passed in to the report. There is another textbox on the right side of the page. I'm observing that when the image's Hidden property is set to "True" then the textbox on the right side stays in the right place. When the image's Hidden property is set to =IFF(1 = 1, true, true), then the textbox on the right is being shifted to the left, and the report looks ugly. How can I have the

问题 I often see code a function defined without visibility keywords. e.g: class Foo() { function bar() { // ... } } Is it a shorthand of public function? Is it a good practice to omit it? class Foo() { public function bar() { //.. } } 回答1: As written in the PHP Doc, Methods declared without any explicit visibility keyword are defined as public. So, yes, in class Foo() { public function bar() { //.. } } Foo::bar() is public, but omitting the visibility keyword is never a good practice. If it's a

问题 In Objective C, when you define an enum, all of the enum values are visible everywhere and clog the global namespace. I would like to make it Java-style and enforce that enums are only accessible thru the enum type name, e.g. with typedef enum { MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY, NUM_OF } Day; I want to make sure that simply calling MONDAY produces compilation error or at least warning, and the only way to access the enum value were something like Day.MONDAY or