IOS

1. the Foundation framework provides many collection classes, such as NSArray, NSMutableArray, NSSet, NSMutableSet, NSDictionary, and NSMutableDictionary. However, these classes can only store data of the OC object type. 2. to store the basic data

1. The Foundation framework provides many collection classes, such as NSArray, NSMutableArray, NSSet, NSMutableSet, NSDictionary, and NSMutableDictionary. However, these classes can only store data of the OC object type. 2. to store the basic data

I recently encountered the image upload function in my project. I have been working on it for two days and will share it with you here. First, you need to upload an image instead of directly uploading the image through a URL. Instead, you need to

Reference-counting memory management remains unchanged in the arc. In arc, there are two methods: Valid and invalid. We can use them together in an app.Use clang (LLVM compiler) or a later version, and specify the "-fobjc-arc" compiler attribute to

Problem description: CGContextRef ctx = UIGraphicsGetCurrentContext ();Why is this error reported: is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability? Is to use an invalid

1. _ advantages of the weak modifier, in addition to solving the problem of loop reference, when holding a weak reference of an object, if the object is discarded, this weak reference will automatically expire and be in the nil assigned State (null

1. Check the xib effect first. Then run it in the simulator. Obviously, the following view is misplaced. Based on experience, possible causes of this problem: 1. The size of the selected view is 4-inch, and the result is 3.5-inch. VcD4KPHA + Mi7

Let's talk about the adaptation between different ios versions. Let's talk about one thing first: In xcode, there is one thing called targets. Apple's official documentation says this: A target specifies a product to build and contains the

Determines whether the device is an ipad. BOOL isPad (){ # Ifdef UI_USER_INTERFACE_IDIOM Return (UI_USER_INTERFACE_IDIOM () = UIUserInterfaceIdiomPad ); # Else Return NO; # Endif } Determine whether the device is iphone5 # Define iPhone5

I thought that the custom cookie could bring cookies in one domain to another domain for use. In fact, the server is not considered to be logically qualified based on the domain and cannot be used in the end. The following code is a key part of the

Continue with previous articles In xcode, you can set the sdk in two other places. One is the Development Target, which indicates the version of the compiled app that can be run on another terminal. The setting method is as follows: The other is

Common classes in the Foundation framework include NSString, NSArray, NSSet, and NSDictionary, and their corresponding NSMutableString, NSMutableArray, NSMutableSet, and NSMutableDictionary. The parent class is mutable and the subclass is variable,

NSOperation. h defines NSOperation. The content is very concise. NSOperation is an abstract class and defines a Task to be executed. NSOperationQueue is a Task queue. After a Task is added to a queue, NSOperationQueue is automatically executed

As we all know, for the sake of security, each app can only use the storage space in its own app sandbox, and each app cannot access each other's sandbox space. In addition, iOS devices do not have external memory cards. In this way, it is

In general, there are two methods to customize UITextView content: 1. Read the content from the file to UITextView. This person feels that the rtfd and rtf files are very effective. 2. Use NSAttributeString for customization The specific method is

When the UISearchDisplayController and UISearchBar in iOS7 are used together, sometimes the search box gets the focus, and the shaded part blocks the search box, which affects user usage, as shown in figure { 　　　for(UIView * v in

The reference is automatically counted in the arc automatic reference counting memory management.Apple official documentation: uses the arc mechanism in oc to allow compilers to manage memory,In the next-generation apple llvm compiler, you do not

1. introduction Runloop is part of the thread-related basic framework and is used to plan event processing. When there is a task, Runloop will let the thread process the task, when there is no task, Runloop will put the thread in sleep state.Runloop

Default navigation bar in iOS 7 Before starting customization, let's take a look at the appearance of the default navigation bar in iOS 7. Use XcodeSingle View ControllerTemplate to create a project. Then, embed the view controller Into a navigation

In map development applications, the use of geographical locations and MKMapView is inseparable. The following describes what you learned when using these two things. However, not all Apple devices support geographic locations. We should make a