foundation

问题 I'm trying to learn about NSTimer , using Foundation and printing to the console. Can anybody tell me what I need to do to get the following to work? It compiles with no errors, but does not activate my startTimer method -- nothing prints. My aim is to get one method to call another method to run some statements, and then stop after a set time. #import <Foundation/Foundation.h> @interface MyTime : NSObject { NSTimer *timer; } - (void)startTimer; @end @implementation MyTime - (void)dealloc {

问题 I'm trying to find out why this piece of code works so strange. You can find details below: let nowDate = Date() let threeDayBeforeNowDate_t1 = Date(timeIntervalSinceNow: -60 * 60 * 24 * 3) let oneDayAfterNowDate = Date(timeIntervalSinceNow: 60 * 60 * 24 * 1) let threeDayBeforeNowDate_t2 = Date(timeIntervalSinceNow: -60 * 60 * 24 * 3) let threeDayBeforeNowDate = nowDate.addingTimeInterval(-60 * 60 * 24 * 3) let diff_1 = threeDayBeforeNowDate_t1.timeIntervalSince(nowDate) -

问题 I got a doubt about how Timer.scheduledTimer() fires the block of code if the execution takes more time than the specified withTimeInterval: . Does the countdown to firing starts after the execution of the block or when the first statement of the block is executed? So I tested with the following code : //Logic is to waste the time in the block which will take more than 5 secs to run. Timer.scheduledTimer(withTimeInterval: 5, repeats: true){ timer in var sum = 0 var count = 0 print("START=====

问题 At my workplace, our app determines the locale of the user session by using a code that is similar to below (though there are various layers of code it passes through before it reaches here at the time of startup, so the problem is/may not evident by running the code below) #include <CoreFoundation/CoreFoundation.h> #include <iostream> #include <string> #include <vector> #include <memory> // Reference release struct reference_close { void operator()(const void *ref) const { CFRelease(static

问题 I know there is a constant for the "CFBundleVersion" plist key - defined as kCFBundleVersionKey in CoreFoundation's CFBundle.h header. But is there a similar constant for "CFBundleShortVersionString" ? 回答1: No, it isn't. The supported keys are kCFBundleInfoDictionaryVersionKey; kCFBundleExecutableKey; kCFBundleIdentifierKey; kCFBundleVersionKey; kCFBundleDevelopmentRegionKey; kCFBundleNameKey; kCFBundleLocalizationsKey; 来源： https://stackoverflow.com/questions/32187359/is-there-a-constant

问题 I'm new to Objective-C, and this is really my first program that is interactive. I've been learning for about 2 weeks now. So, my question is: typically I've noticed when you have multiple scanf 's in a row, they each wait for input - however in this situation, where I ask for account owner name, and balance - it fires both NSLog functions instead of waiting for the first input. Here is my main: int main(int argc, char* argV[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

问题 From Apple's documentation: Return Value A range describing the intersection of range1 and range2—that is, a range containing the indices that exist in both ranges. Discussion If the returned range’s length field is 0, then the two ranges don’t intersect, and the value of the location field is undefined. Okay, so let's say I have two ranges: (lldb) p rangeOne (NSRange) $3 = location=11, length=4 (lldb) p rangeTwo (NSRange) $4 = location=14, length=0 And I calculate the intersection: NSRange

问题 In C# I can convert any char from my string to integer in the following manner intS="123123"; int i = 3; Convert.ToInt32( intS[i].ToString()); What is the shortest equivalent of this code in Objective-C ? The shortest one line code I've seen is [NSNumber numberWithChar:[intS characterAtIndex:(i)]] 回答1: Many interesting proposals, here. This is what I believe yields the implementation closest to your original snippet: NSString *string = @"123123"; NSUInteger i = 3; NSString

问题 When using URLComponents 's queryItems I've found that if you have a query item whose value contains some percent encoded characters, in my case a / being encoded as %2F , then if you construct a URLComponents object from a String URL that contains such a query item, then mutate the list of query items for the URLComponents object, then if you try to get a URL by calling .url on the URLComponents object, then the query items lose their percent encoding. Here's the code I've been testing this

问题 I need a little guidance on best practice with URLSession/NSURLSession . My requirement stipulates that I have to do adhoc/periodic HTTP GET requests. i.e. Every few mins, then maybe every 30 seconds, changing at will. Anyway I've achieved this as follows, I have a method that contains code like this: let urlRequest = URLRequest(url: url) // set up the session let config = URLSessionConfiguration.default let session = URLSession(configuration: config) // make the request let task = session