IOS

Sometimes, if you want to run a piece of code after a certain period of time, you need to use delayed execution. There are several common methods: 1. The most direct method is performSelector: withObject: afterDelay: the disadvantage of this method:

In the Windows era, you must have some knowledge about SendMessage, PostMessage, and GetMessage. These are all message processing functions in windows. What is corresponding to in ios? In fact, they are just the content of the nsunloop. In ios, all

Use the http request jsp to return the updated content Starttime) {map. put ("sale", "to thank new and old customers for their love,... discount information. ");} If (dv = 1.00) | (dv

# UserDefault tips# Version numbers must be added to UserDefault for version-related variables> For example, hasShowGuide // whether the boot page is displayed>, It should be hasShowGuide1_1_0# The added version number should be obtained using

Note that you should introduce AudioToolbox. framework. The test passed on iOS6 and iOS7. Private APIs are risky. Do not use them in apps. NSMutableDictionary* dict = NSMutableArray* arr = [arr addObject:[NSNumber numberWithBool:YES]]; [arr

1. Why do I need to set it to nil after a variable is release? After a variable is release, the memory to which the variable points is released, but the variable itself remains unchanged and still points to the original memory address. If this

// To execute the notification, you must exit the application or suspend the application (enter the background) to receive the notification. // Create a local notification UILocalNotification *notification = [[UILocalNotification alloc] init]; //

When developing a project, I encountered a problem: In my UIScrollViewOut, A UIScrollViewIn is embedded, When I want to drag UIScrollViewIn, UIScrollViewOut changes, while UIScrollViewIn does not. However, you only need to press and hold

I have added a new knowledge in iOS5, that is, ARC. In fact, I don't like it very much because I am used to managing the memory myself. However, learning is still necessary. During iOS development, attribute definitions are often related to retain,

Dictionary Traverse dictionaryNSLog (@ "*** traverse the dictionary myClassDict as follows :"); For (id key in myClassDict) { NSLog (@ "key: % @, value: % @", key, [myClassDict objectForKey: key]); } [_ SurveyAnswers1 setObject: myArrayAnswers1

EXC_BAD_ACCESS. The error is generally caused by automatic release, which is essentially a memory management problem. SIGABRT. errors are generally caused by Invalid methods or attributes of the object or type. For example, [NSNull null] length

IPhone/iPad development Simulator screenshots Command + Shift + 3Capture entire screen and save as a fileCapture the entire screen and save the png file to the desktop Command + Control + Shift + 3Capture entire screen and copy to the

Introduction to iOS Dev (44) SKTextureAtlas   Header file definition SpriteKit/SKTextureAtlas. h#import #import SK_EXPORT @interface SKTextureAtlas : NSObject + (SKTextureAtlas *)atlasNamed:(NSString *)name;-

On the 2011 WWDC, Apple released GCD, which adds a new method for multithreading. GCD must run in iOS or later or OS X10.6 or later. GCD, short for Grand Central Dispatch, is a group of C interfaces used to implement concurrent programming. GCD is

Notes for using loadView in iOS Dev (43)   Never take the initiative to call the loadView MethodViewController calls loadView when the view attribute is requested and the current view is nil.If you use xib to create a view and initialize

Today, when I was working on a project, I used the UIWebView class to browse the Web page.Let's take a look at what this class has.In fact, this class is relatively simple.UIWebViewInherited from UIViewThis class can be used to easily implement web

IOS Dev (38) You may not understand the main. m file   First look at the code#import #import AppDelegate.hint main(int argc, char * argv[]){ @autoreleasepool { return UIApplicationMain(argc, argv, nil,

IOS Dev (39) Do you understand UIApplicationDelegate?  

: It is to pass the value of the first interface to the second interface for display. Its simple implementation method is as follows: // Create the second VCTRsceondViewController * sceondViewController = [[TRsceondViewController alloc]

We found that map and location functions are introduced in many social software. If we want to implement these two functions, we need to use two frameworks: Let's first look at the frameworks: and the frameworks: [_mapView