subclass - w3toppers.com

Make Background of UIView a Gradient Without Sub Classing

You can use +[UIColor colorWithPatternImage:] to produce a patterned background. Example (bring your own CGGradient): // Allocate color space CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // Allocate bitmap context CGContextRef bitmapContext = CGBitmapContextCreate(NULL, 320, 480, 8, 4 * 320, colorSpace, kCGImageAlphaNoneSkipFirst); //allocate myGradient CGFloat locationList[] = {0.0f, 1.0f}; CGFloat colorList[] = {0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, … Read more

Rotating a view in layoutSubviews

The problem with the code in the question seems to be that the transformations keep getting added to each other. In order to fix this, the solution is to reset the transformations every time, that is, set it to the identity transform. rotationView.transform = CGAffineTransformIdentity Here is a partial implementation that shows the key parts. … Read more

Call protected method from a subclass of another instance of different packages

Don’t know the rationale, but JLS confirms this in 6.6.2. Details on protected Access (emphasis mine): A protected member or constructor of an object may be accessed from outside the package in which it is declared only by code that is responsible for the implementation of that object. So: package P2; public class P2 { … Read more

Delphi subclass visual component and use it

The closest equivilent to your XCode approach is to use an “interposer” class in Delphi. Basically, you do not change the code that the IDE creates for the standard TToolBar usage. You instead declare a new class that derives from the standard TToolBar component but is also named TToolBar and you make it visible to … Read more

Call subclass’s method from its superclass

You can, as Objective C method dispatch is all dynamic. Just call it with [self methodOfChild], which will probably generate a compiler warning (which you can silence by casting self to id). But, for the love of goodness, don’t do it. Parents are supposed to provide for their children, not the children for their parents. … Read more

Why subclass in another package cannot access a protected method?

Protected methods can only be accessible through inheritance in subclasses outside the package. And hence the second approach tryMeProtected(); works. The code below wont compile because we are not calling the inherited version of protected method. Class1 c = new Class1(); c.tryMeProtected(); // ERROR: tryMeProtected() has protected access in Class1 Follow this stackoverflow link for … Read more

Should I subclass the NSMutableArray class

NSMutableArray is not a concrete class, it is just the abstract superclass of a class cluster. The documentation for NSMutableArray does have information about how to subclass, but also strongly advises you not to! Only subclass if you have a special need for actual storage. A class cluster means that the actual class will be … Read more

How can I change the default value of an inherited dependency property?

The correct way to override a base class’s property is: static TestControl() { FooProperty.OverrideMetadata( typeof(TestControl), new FrameworkPropertyMetadata(67) ); } EDIT: AddOwner is meant to share the same DependencyProperty across types that are not related (i.e. the TextProperty of TextBox and TextBlock).

In C# 4.0, is it possible to derive a class from a generic type parameter?

Generic types in C# are not C++ templates; remember, a generic type must work for all possible type arguments. A template need only work for the constructions you actually make. This question is a duplicate; see my answer to Why cannot C# generics derive from one of the generic type parameters like they can in … Read more

Swift + CoreData: Cannot Automatically Set Optional Attribute On Generated NSManagedObject Subclass

The optional checkbox in the Core Data Model Editor has been existing before Swift and its optionals where introduced. Apple states about it in its Core Data Programming Guide: You can specify that an attribute is optional — that is, it is not required to have a value. In general, however, you are discouraged from … Read more