cocoa

问题 Please, could you give a simple complete example of Cocoa application with NSOutlineView with hierarchical data representation not so ambiguous like NSOutlineView and NSTreeController example . Thanks! 回答1: This example uses a simple two layer hierarchy of two parents Foo and Bar who each have two kids, Foox, Fooz and Barx, Barz respectively, the outline view is the default one with just two columns and the identifier of the second column is set to "children". NSDictionary *firstParent = @{@

问题 I've got a text file, with about 200,000 lines. Each line represents an object with multiple properties. I only search through one of the properties (the unique ID) of the objects. If the unique ID I'm looking for is the same as the current object's unique ID, I'm gonna read the rest of the object's values. Right now, each time I search for an object, I just read the whole text file line by line, create an object for each line and see if it's the object I'm looking for - which is basically

问题 I've got a text file, with about 200,000 lines. Each line represents an object with multiple properties. I only search through one of the properties (the unique ID) of the objects. If the unique ID I'm looking for is the same as the current object's unique ID, I'm gonna read the rest of the object's values. Right now, each time I search for an object, I just read the whole text file line by line, create an object for each line and see if it's the object I'm looking for - which is basically

问题 I've got a text file, with about 200,000 lines. Each line represents an object with multiple properties. I only search through one of the properties (the unique ID) of the objects. If the unique ID I'm looking for is the same as the current object's unique ID, I'm gonna read the rest of the object's values. Right now, each time I search for an object, I just read the whole text file line by line, create an object for each line and see if it's the object I'm looking for - which is basically

问题 I am playing around with Swift and am stumbling over the following problem: given I have the predefined class Animal : //Predefined classes class Animal { var height: Float = 0.0 } I now write the class Zoo with the constructor accepting animals. But the Zoo wants every animal to have a name and hence defines the Namable protocol. protocol Namable { var name: String {get} } class Zoo { var animals: Animal[] = []; } How would you write an addAnimal method that requires the object being passed

问题 I am playing around with Swift and am stumbling over the following problem: given I have the predefined class Animal : //Predefined classes class Animal { var height: Float = 0.0 } I now write the class Zoo with the constructor accepting animals. But the Zoo wants every animal to have a name and hence defines the Namable protocol. protocol Namable { var name: String {get} } class Zoo { var animals: Animal[] = []; } How would you write an addAnimal method that requires the object being passed

问题 I created a new project and selected Cocoa App and pressed next and found that Objective C was the only language available. I clicked on Help | What's new in Xcode Menu and it says that the swift language and lang support are the new features. What's wrong here? UPDATE: I updated the product from the Apple site. Despite the documentation that came with Xcode saying that Swift is part of this release, why can't I get to use swift? By the way, the Xcode version is: Version 6.0 (6A313). 回答1: As

问题 If a folder is placed in the Dock you can sort it by "date added" - this is usually the default for the Downloads folder. (Sometimes the Finder does not appear to be using the date added but the date modified, but it can find the date added.) Where is the Finder figuring this out from? The standard file metadata, i.e. as obtained by stat, getattrlist or FSGetCatInfo) does not contain it. TIA 回答1: Yep, the date added could be inferred from other structures. In fact, it resides in Spotlight

问题 This just started today. Autocomplete had been working fairly well and then started sputtering, only showing autocomplete for some standard Cocoa classes / methods etc. Best described as periodic strange omissions. I am using Cocoa & Objective C but it seems to be broken for more than just Objective C . I deleted the derived data and it had no effect. (default is ~/Library/Developer/Xcode/DerivedData but I like to keep in my project folders for easy delete) Xcode is so huge (like an operating

问题 I need to access sidecar XMP files in a document-based photo editor application. The image files are the documents, and I need to access the sidecar XMP file when the user open and save an image document. Is it possible to access sidecar files (such as XMP) in a sandboxed document-based application? I understand that it's not possible by default, but what is the minimal temporary security exception that is needed to allow that? Is there a workaround for this without using temporary exception?