Objective-C

The general principle is that small storage capacity data types can be automatically converted into large storage-capacity data types, depending on the type of data consumed and the type conversion or coercion. Different types of data are

Objective-C in different ways to achieve the lock (a) Why need to use locks, of course, familiar with multi-threaded you, naturally will not feel strange to it. Did you use the lock mechanism well in the code? Do you know several ways to implement

First, why use multithreading?1, cycle simulation time-consuming task1. Synchronous execution2. Asynchronous execution(Small Secretary for cigarette programming)3. ProcessAn application that is running in the systemEach process is independent and

UIWebView is one of the most commonly used SDKs for iOS, and it has a stringbyevaluatingjavascriptfromstring method to embed JavaScript in the page, In this way we can interact with the page elements in UIWebView in

Understand Variable Scope Variable abandonment Holding objects Releasing objects Object owner (reference count) Object abandonment The effect of variable ownership modifiers on objects Objects holding each

The overall architecture of iOS (take iOS8 as an example) is shown below:From cocoa touch to core OS the four tiers below contain all the APIs that are used to develop iOS applications (third-party frameworks are based on these layers). Each layer

I. Grammatical specifications1. Class: Abstract description of a thing, such as the abstraction of humans, dogs and cats into animal classesTwo files in OC to describe a class1>. H: declaration file for a class declaring member variables and methods,

1. Is it possible to put more time-consuming operations in the notification Center?  Notice in which line Cheng, then the processing of the notification event is carried out in the same thread;if the asynchronous line Cheng the notification, then

OutlineNsarrayNsmutablearrayQuick EnumerationNsarray　　Nsarray is a static array, which is a non-variable group that cannot be added, deleted, or modified once it is created. Nsarray inherits from NSObject, which manages a collection of ordered

　　In object-oriented languages, many different implementations of interfaces are polymorphic. Polymorphism responds to different objects in response to the same method, polymorphism in code, that is, a variety of forms, must have inheritance, no

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Here we customize a Carousel diagram Class Imageloop inherits from UIView, and the class Imageloop contains a Uiscrollview and Uipagecontrol, which defines three properties:Pagecontroll,position,currentpage can customize the Pagecontrol style, or

C # has written that C # is particularly handy for reading and writing the properties of an object through reflection, and can be used to dynamically control an object in the form of a string. In fact, in the OBJC, we can be more advanced point, do

Shallow copyA shallow copy is a copy of the memory address, so that the target object pointer and source object point to the same piece of memory space. Such as:char* str = (char*) malloc (+); char* str2 = str;A shallow copy is simply a simple copy

Today we are going to talk about the compound , of course, not a small couple arguing to break up, and then together in the compound.　　A composite follows a synthetic reuse principle , also known as a combination or aggregation multiplexing

In fact, I don't know how to write these concepts. I can't copy them directly from a book. It's better to buy books. Abstract concepts are generally written by masters. For example, this can be the Java programming idea of a pillow. That's really an

1. General setter and getter statements Setter and getter are the most basic things of a class. Any object-oriented language involves the concept of C ++ and Java. Because setter and getter are the most basic support for object-oriented language

Discussing a strange concept of objective-C: meta-class Every class in objective-C has its own meta-class, but it is mysterious because you seldom use meta-class directly. Create a class at runtime The following code creates a new nserror subclass

We know that the message sending program to nil in Objective-C will not crash, Objective-C is based on the C language, On PC, null pointer operations are performed in C language, The program crashes due to a protection error due to out-of-bounds