Objective-C

String vs NSString JavaScript String obj-c NSString CharAt (Index) (See text) charCodeAt (Index) -(Unichar) Characteratindex: (nsuinteger) index Concat (String)

Objective-c Object Initialization Objects Initialization1.1 Allocating Objects Assignment ObjectAllocation is the process by which a new object is born.Allocation is the process of the birth of new objects.Sending the ALLOC message to a class causes

First, learn about OC beforeIntroduction to OC Syntax Keywords begin with @; The string starts with @, such as NSLog (@ "I love iOS."); Import can automatically prevent the contents of the file from being copied repeatedly;

@class and #importDescriptionA forward reference was created @class. This is telling the compiler: "Trust me." You will naturally know what this class is, but now you know it is enough. ”@class can also be useful if you have circular dependencies.

Objective-c can fully automate the memory management of the program, relying mainly on the management mechanism of reference counting in the Objective-cFirst of all:The guidelines for memory management are: If you use Class A for an object.

One, the visibility of instance variables (access rights)Second, the methodThere are two types of methods in OC: Class, method and instance? method.Class? Method: Can only be used for class, for example: + (ID) Alloc Note: Class? Method cannot be

SuperIn Objective-c, if we need to invoke a method of the parent class in a method of a class, we usually use Super, as follows:@interface Myviewcontroller:uiviewcontroller @end @implementation Myviewcontroller-(void) viewdidload { [super

Here is an example I wrote to test how Objective-c uses the class'sTestClass.h testclass.h// testclass//// Created by exchen on 6/15/15.// Copyright (c) exchen. All rights reserved.//#import @interface testclass:nsobject{ //public member

These days the programming with Objective-c again looked aside, found a lot of previously unclear places. Now write down some important points and consolidate the learning effect.1.objective-c Classes is also Objects (OC class is also an object)In

The methods of variable parameters are not uncommon in objective-c, and many common methods like cocoa are variable parameters, such as:1 NSLog (NSString *format, ...) 2 + (ID) arraywithobjects: (ID) firstobj, ... 3 + (ID)

Introduction to Associations in OBJECTIVE-CReprint please indicate the source of CSDN blog:http://blog.csdn.net/daiyibo123/article/details/46471993How to set associationsWe can use the following methods to correlate properties:objectconstvoidvalue,

Use of blocks (block) //No parameter no return value void(^message) (void) = ^{NSLog (@"Hello world!\n"); }; //have a parameter return valueNSString * (^repeat) (NSString *,int) = ^ (NSString *str,intTimes )

the practical function of category is to add methods to existing classes. The methods added for the existing classes can be implemented without implementation and can be implemented again when needed. How do we implement category in our actual

Brief introductionBased on the C language, you can build a class that requires two files by writing a single-C + + code: . h's header file . m implementation file (if it is a mixed-C + + file with a. mm file suffix) Since there is a header file, so

OBJECTIVE-C protocols?1.1 Formal protocols?A formal protocol (like the informal protocol) is a named list of methods and properties.Formal protocol (like informal protocol) is a list of names for a series of methods and properties.However, a formal

#pragma mark-block SyntaxNSLog(@ "========block method 1==========="); [Students sortusingcomparator: ^nscomparisonresult(ID obj1, ID obj2) { Student *stu1 = (Student *) obj1; the obj1 here is the Student type. Student *stu2 = (Student *)

Today the main practice nsstring nsmutablestring Nsarray NsmutablearrayNSString ( string)Method 1: [[NSString alloc] initwithformat:@ ""] creates a string object, formats it, and assigns a value to the string object method 2:stringwithformat:@ ""

The contents of these days are mostly methods, may be seen in the time feel there is nothing to learn, but these things will be involved in the follow-up, it is best to be able to knock again, so in the back of the time will not feel

Operators can be divided into the following types:Arithmetic operators: +,-, *,/,%,++,—-。Relational operators: ,=,==,!=Boolean logical operators:! , &&,| |Bitwise operator:|,&,^,~,>>,Assignment operators: + =,-=, *=, =/Conditional

1. Main function2. Uiapplicationmain* Create UIApplication objects* Create a UIApplication delegate object3.1 Delegate agent starts processing (listening) system events (No Storyboard)* When the program is started, the agent's