non-nullable

问题 RequireSome type from another, very simialar question. This question is similar but it should not be a duplicate since here we want to also remove null as well as undefined from properties. Maybe the name shouldn't be Require but something like NonNullable or of this kind. The goal of this type is to specify which fields from a type should not be undefined or null, and return their types without undefined and null. type Question = { id: string; answer?: string | null; thirdProp?: number |

问题 I am using Thread for some Async operations. Now primarily I have 3 Threads like : private lateinit var horse1Thread: Thread private lateinit var horse2Thread: Thread private lateinit var timerThread: Thread Calling stop() in onDestroy() of activity causes a UnsupportedOperationException and I thought of setting these values to null to allow GC collection and prevent memory leak. Since my fields are non-null types I cant set them to null . So is this my only option? Or does kotlin provide a

问题 If I enable nullable reference types, what will be the value of the following string if I declare it like so? string text; 回答1: The value will be null . Bear in mind that the new system for nullable reference types will only warn you about problems, it will not give you an error , and that means that the code will still compile, with warnings. If you declare this class: public class Test { private string text; } You'll get this warning for your class: CS8618: Non-nullable field 'text' is

来源： https://stackoverflow.com/questions/61387407/android-annotation-nonnull-is-not-public-in-android-annotation-cannot-be-ac

问题 So you can't inherit string . You can't make a non-nullable string . But I want to do this. I want a class, let's call it nString that returns a default value when it would otherwise be null. I have JSON objects that might have who knows how many null strings, or even null objects. I want to create structs that have strings that will never return null. public struct Struct { public nString value; public nString value2; } I suppose I could do something like this: public struct Struct { public

问题 So you can't inherit string . You can't make a non-nullable string . But I want to do this. I want a class, let's call it nString that returns a default value when it would otherwise be null. I have JSON objects that might have who knows how many null strings, or even null objects. I want to create structs that have strings that will never return null. public struct Struct { public nString value; public nString value2; } I suppose I could do something like this: public struct Struct { public

问题 I am writing algorithms that work on series of numeric data, where sometimes, a value in the series needs to be null. However, because this application is performance critical, I have avoided the use of nullable types. I have perf tested the algorithms to specifically compare the performance of using nullable types vs non-nullable types, and in the best case scenario nullable types are 2x slower, but often far worse. The data type most often used is double, and currently the chosen

问题 I keep hearing people talk about how non-nullable reference types would solve so many bugs and make programming so much easier. Even the creator of null calls it his billion dollar mistake, and Spec# has introduced non-nullable types to combat this problem. EDIT: Ignore my comment about Spec#. I misunderstood how it works. EDIT 2: I must be talking to the wrong people, I was really hoping for somebody to argue with :-) So I would guess, being in the minority, that I'm wrong, but I can't

问题 How can I remove the default value that is added by default to the textboxes of non nullable properties when using the EditFor helper? I don't want that behavior EDIT Sorry I didn't give enough information. For example if you use Html.EditorFor with a property that is DateTime it will set the textbox value to 1/1/0001 automatically. If you use "DateTime?"(nullable), it won't, it just leaves the textbox empty. 回答1: You can use UIHint to do it. Create a file called ShortDate.cshtml in

问题 When configuring Eclipse 4.2.0 to perform a null analysis (configured to use @javax.annotation.Nonnull etc.), the following code will generate the warning Null type safety: The expression of type int needs unchecked conversion to conform to '@Nonnull Integer' class C { static void foo(int i) { bar(i); // Warning } static void bar(@javax.annotation.Nonnull Integer i) { } } How am I supposed to fix this (without using @SuppressWarnings("null") )? It seems that the analyzer does not know that