I wanted to move to TypeScript from traditional JS because I like the C#-like syntax. My problem is that I can’t find out how to declare static classes in TypeScript. In C#, I often use static classes to organize variables and methods, putting them together in a named class, without needing to instatiate an object. … Read more
I’m trying to create a custom view GhostSurfaceCameraView that extends SurfaceView. Here’s my class definition file GhostSurfaceCameraView.java: public class GhostSurfaceCameraView extends SurfaceView implements SurfaceHolder.Callback { SurfaceHolder mHolder; Camera mCamera; GhostSurfaceCameraView(Context context) { super(context); // Install a SurfaceHolder.Callback so we get notified when the // underlying surface is created and destroyed. mHolder = getHolder(); mHolder.addCallback(this); mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); … Read more
I am using selenium for end to end testing and I can’t get how to use setup_class and teardown_class methods. I need to set up browser in setup_class method, then perform a bunch of tests defined as class methods and finally quit browser in teardown_class method. But logically it seems like a bad solution, because … Read more
I’m writing some code that takes a filename, opens the file, and parses out some data. I’d like to do this in a class. The following code works: class MyClass(): def __init__(self, filename): self.filename = filename self.stat1 = None self.stat2 = None self.stat3 = None self.stat4 = None self.stat5 = None def parse_file(): #do some … Read more
I observed that Outer classes can access inner classes private instance variables. How is this possible? Here is a sample code demonstrating the same: class ABC{ class XYZ{ private int x=10; } public static void main(String… args){ ABC.XYZ xx = new ABC().new XYZ(); System.out.println(“Hello :: “+xx.x); ///Why is this allowed?? } } Why is this … Read more
I am interating through classes in a Jar file and wish to find those which are not abstract. I can solve this by instantiating the classes and trapping InstantiationException but that has a performance hit as some classes have heavy startup. I can’t find anything obviously like isAbstract() in the Class.java docs. 3 Answers 3
In Java, it is perfectly legal to define final arguments in interface methods and do not obey that in the implementing class, e.g.: public interface Foo { public void foo(int bar, final int baz); } public class FooImpl implements Foo { @Override public void foo(final int bar, int baz) { … } } In the … Read more
What’s the standard way to call static methods? I can think of using constructor or using the name of the class itself, I don’t like the latter since it doesn’t feel necessary. Is the former the recommended way, or is there something else? Here’s a (contrived) example: class SomeObject { constructor(n){ this.n = n; } … Read more
Say I have this: <div class=”class1 class2″></div> How do I select this div element? document.getElementsByClassName(‘class1’)[0].getElementsByClassName(‘class2’)[0] That does not work. I know that, in jQuery, it is $(‘.class1.class2′), but I’d like to select it with vanilla JavaScript. 8 Answers 8
I understand PHP does not have a pure object variable, but I want to check whether a property is in the given object or class. $ob = (object) array(‘a’ => 1, ‘b’ => 12); or $ob = new stdClass; $ob->a = 1; $ob->b = 2; In JS, I can write this to check if variable … Read more