IOS code Specification

Core principles

Writing elegant code is like organizing a room, so that the code structure is a tree with branches. Everything a program does is passing and branching information.

The code should be simple and easy to understand, logical, modular code

Clean code is easy to spot bugs, and you need to write code that is obviously bug-free, not bug-free
Avoid writing functions that are too long. Functions should be no longer than 40 lines, which is about the height of the viewing Angle on the screen, and logically break up smaller functions
Make small utility functions, and pull out the duplicate code to make functions, although some of the duplicate code is only 2 lines long, and extract it to make functions can simplify the logic in the main function
Each function does one simple thing,

For example, we might sometimes write “generic” functions that are chosen to do what they do based on internal criteria

func foo() { if getOS().equals("MacOS") { a(); } else { b(); } c(); If getOS().equals("MacOS") {d(); } else { e(); }}Copy the code


func fooMacOS() {
  a();
  c();
  d();
}

func fooOther() {
  b();
  c();
  e();
}

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Write readable code

Increase the expressiveness of programming languages, using meaningful function and variable nouns that can realistically describe their logic

Put (elephant1, Fridge2) is obviousCopy the code

Local variables should be as close to where they are used as possible, short and not reusable, and repeated assignments can be confusing.

Example:

int index = ... . . . Bar (index) may not use index in the middle or change the dependent data, so it is easy to read it as if it is storing some kind of changed data, or has been modified in the middle. If you put index in the bottom, you know that index does not hold variable values. I didn't make any changesCopy the code

. . . int index = ... bar(index)Copy the code

Remove the complicated logic and make it a helper function
Extract the complex expression, make it intermediate variables, taboo deep nesting


make.left.equalTo(view.snp.left).offset(10) 

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Programming for change, not requirements

Requirements are only temporary, code is not easy to meet requirements, write extensible and easy to modify the program, the code is your lover

Code specification

class

The layout of the class

When classifying the layout, you can specify what the function points are

#pragma mark - Life Cycle Methods
- (instancetype)init
- (void)dealloc

- (void)viewWillAppear:(BOOL)animated
- (void)viewDidAppear:(BOOL)animated
- (void)viewWillDisappear:(BOOL)animated
- (void)viewDidDisappear:(BOOL)animated

#pragma mark - Override Methods

#pragma mark - Intial Methods

#pragma mark - Network Methods

#pragma mark - Target Methods

#pragma mark - Public Methods

#pragma mark - Private Methods

#pragma mark - UITableViewDataSource  
#pragma mark - UITableViewDelegate  

#pragma mark - Lazy Loads

#pragma mark - NSCopying  

#pragma mark - NSObject Methods

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Abnormal handling of fetching interface

On the UI side, warning handling and error handling on each interface need to be considered, not just empty data, in case of unnecessary problems

variable

Variable names are humped

Classes, protocols use large hump objects and other local variables use small hump


HomePageViewController.h
<HeaderViewDelegate>

NSString *personName = @"";
NSUInteger totalCount = 0;

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Variable names contain function and type

UIButton *addBtn // Add button UILabel *nameLbl // name tag NSString *addressStr// Address stringCopy the code

The system often adds suffixes to class instance variable declarations

Type/suffix UIViewController VC UIView View UILabel Lbl UIButton Btn UIImage Img UIImageView ImagView NSArray Array NSMutableArray Marray NSDictionary Dict NSMutableDictionary Mdict NSString Str NSMutableString Mstr NSSet Set NSMutableSet Mset

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attribute

Attributes are named using small humps
Instantiating an object costs resources, and if a property in the object requires “a lot of configuration and calculation “, we can use lazy loading, loading it just before it is used

- (NSDateFormatter *)dateFormatter 
{
    if(! _dateFormatter) { _dateFormatter = [[NSDateFormatter alloc] init]; NSLocale *enUSPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
           [_dateFormatter setLocale:enUSPOSIXLocale];
           [_dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSS"];
    } 
    return _dateFormatter;
}

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NSArray&NSMutableArray

AddObject does a non-null check, takes a subscript to see if it’s out of bounds, and you can initialize the array with lazy load before you get the data

The operator

There is no space between unary operators and variables

! isTopCopy the code

Space between binary budget symbols


3 + 1

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annotation

Special logic processing
API branch processing, when required, indicates the ipA call
Use run-time method exchange, indicated

IOS code Specification