1.建议用.符号代替括号用于设置或获取属性值
For example:
view.backgroundColor = [UIColororangeColor];[UIApplicationsharedApplication].delegate;
Not:
[viewsetBackgroundColor:[UIColororangeColor]];
UIApplication.sharedApplication.delegate;
2.空格
a.缩进必须使用4个空格。没有缩进和制表符。
b.一定要在Xcode中设置此首选项。方法括号和其他括号(如果/其他/开关/等等)。必须打开在同一行语句。括号必须关闭在一个新行。
For example:
if(user.isHappy) {
// Do something
}
else{
// Do something else
}
3.条件语句：必须有括号
For example:
if(!error) {returnsuccess;}
Not:
if(!error)returnsuccess;
or
if(!error)returnsuccess;
4.三元运算符：三元操作符的意图,?,是增加清晰或代码整洁。三元应该只评估每一个条件表达式。评估多个条件通常是更容易理解作为一个if语句或重构命名变量。
For example:
result = a > b ? x : y;
Not:
result = a > b ? x = c > d ? c : d : y;
5.错误处理：当方法返回一个错误参数通过引用,代码必须打开返回值,不得打开错误变量。
For example:
NSError*error;if(![selftrySomethingWithError:&error]) {// Handle Error}
Not:
NSError*error;[selftrySomethingWithError:&error];if(error) {// Handle Error}
6.方法
For example:
- (void)setExampleText:(NSString*)text image:(UIImage *)image;
7.变量：见名知意
For example:
NSString *title: It is reasonable to assume a “title” is a string.
NSString *titleHTML: This indicates a title that may contain HTML which needs parsing for display.“HTML” is needed for a programmer to use this variable effectively.
NSAttributedString *titleAttributedString: A title, already formatted for display.AttributedStringhints that this value is not just a vanilla title, and adding it could be a reasonable choice depending on context.
NSDate *now:No further clarification is needed.
NSDate *lastModifiedDate: SimplylastModifiedcan be ambiguous; depending on context, one could reasonably assume it is one of a few different types.
NSURL *URLvs.NSString *URLString: In situations when a value can reasonably be represented by different classes, it is often useful to disambiguate in the variable’s name.
NSString *releaseDateString: Another example where a value could be represented by another class, and the name can help disambiguate.
Single letter variable names are NOT RECOMMENDED, except as simple counter variables in loops.
Asterisks indicating a type is a pointer MUST be “attached to” the variable name.For example,NSString *textnotNSString* textorNSString * text, except in the case of constants (NSString * const NYTConstantString).
For example:
interfaceNYTSection:NSObject@property(nonatomic)NSString*headline;@end
Not:
@interfaceNYTSection:NSObject{NSString*headline;}
8.变量限定符：
For example:
NSString * __weak text.
9.命名：描述性的方法和变量名越清楚越好
For example:
UIButton *settingsButton;
Not
UIButton *setBut;
For example:
staticconstNSTimeIntervalNYTArticleViewControllerNavigationFadeAnimationDuration =0.3;
Not:
staticconstNSTimeIntervalfadetime =1.7;
For example:
@synthesize descriptiveVariableName = _descriptiveVariableName;
Not:
idvarnm;
10.分类
类别建议简明地细分功能,用来描述该功能
For example:
@interfaceUIViewController(NYTMediaPlaying)@interfaceNSString(NSStringEncodingDetection)
Not:
@interfaceNYTAdvertisement(private)
@interfaceNSString(NYTAdditions)
For example:
@interfaceNSArray(NYTAccessors)- (id)nyt_objectOrNilAtIndex:(NSUInteger)index;@end
Not:
@interfaceNSArray(NYTAccessors)
- (id)objectOrNilAtIndex:(NSUInteger)index;
@end
11.注释
When they are needed, comments SHOULD be used to explainwhya particular piece of code does something. Any comments that are used MUST be kept up-to-date or deleted.
Block comments are NOT RECOMMENDED, as code should be as self-documenting as possible, with only the need for intermittent, few-line explanations. This does not apply to those comments used to generate documentation.
12.init and dealloc
dealloc方法应放置在顶部的实现,直接放在@ synthesize和@dynamic语句之后。init方法应该直接放置在dealloc任何类的方法。
- (instancetype)init {
self = [superinit];// or call the designated initializer
if(self) {
// Custom initialization
}
returnself;
}
12.文字
For example:
NSArray*names = @[@"Brian",@"Matt",@"Chris",@"Alex",@"Steve",@"Paul"];NSDictionary*productManagers = @{@"iPhone":@"Kate",@"iPad":@"Kamal",@"Mobile Web":@"Bill"};NSNumber*shouldUseLiterals = @YES;NSNumber*buildingZIPCode = @10018;
Not:
NSArray*names = [NSArrayarrayWithObjects:@"Brian",@"Matt",@"Chris",@"Alex",@"Steve",@"Paul",nil];
NSDictionary*productManagers = [NSDictionarydictionaryWithObjectsAndKeys:@"Kate",@"iPhone",@"Kamal",@"iPad",@"Bill",@"Mobile Web",nil];
NSNumber*shouldUseLiterals = [NSNumbernumberWithBool:YES];
NSNumber*buildingZIPCode = [NSNumbernumberWithInteger:10018];
13.CGRECT
For example:
CGRectframe = self.view.frame;CGFloatx = CGRectGetMinX(frame);CGFloaty = CGRectGetMinY(frame);CGFloatwidth = CGRectGetWidth(frame);CGFloatheight = CGRectGetHeight(frame);
Not:
CGRectframe = self.view.frame;
CGFloatx = frame.origin.x;
CGFloaty = frame.origin.y;
CGFloatwidth = frame.size.width;
CGFloatheight = frame.size.height;
14.常量
For example:
staticNSString*constNYTAboutViewControllerCompanyName =@"The New York Times Company";staticconstCGFloatNYTImageThumbnailHeight =50.0;
Not:
#defineCompanyName@"The New York Times Company"
#definethumbnailHeight2
15.枚举
Example:
typedefNS_ENUM(NSInteger, NYTAdRequestState) {
NYTAdRequestStateInactive,
NYTAdRequestStateLoading
};
16.在处理位掩码时,必须使用NS_OPTIONS宏。
Example:
typedefNS_OPTIONS(NSUInteger, NYTAdCategory) {
NYTAdCategoryAutos =1<<0,
NYTAdCategoryJobs =1<<1,
NYTAdCategoryRealState =1<<2,
NYTAdCategoryTechnology =1<<3
};
17.私有方法：
Private properties SHALL be declared in class extensions (anonymous categories) in the implementation file of a class.
For example:
@interfaceNYTAdvertisement()
@property(nonatomic,strong) GADBannerView *googleAdView;
@property(nonatomic,strong) ADBannerView *iAdView;
@property(nonatomic,strong) UIWebView *adXWebView;
@end
18.图片名称
图片应该命名为一个驼峰式大小写字符串的描述他们的目的,其次是无前缀的名称他们定制的类或属性(如果有的话),其次是进一步描述颜色和/或位置,最后他们的状态。
For example:
RefreshBarButtonItem/RefreshBarButtonItem@2xandRefreshBarButtonItemSelected/RefreshBarButtonItemSelected@2x
ArticleNavigationBarWhite/ArticleNavigationBarWhite@2xandArticleNavigationBarBlackSelected/ArticleNavigationBarBlackSelected@2x.
18.boolen
Values MUST NOT be compared directly toYES, becauseYESis defined as1, and aBOOLin Objective-C is aCHARtype that is 8 bits long (so a value of11111110will returnNOif compared toYES).
For an object pointer:
if(!someObject) {}if(someObject ==nil) {}
For aBOOLvalue:
if(isAwesome)if(!someNumber.boolValue)if(someNumber.boolValue ==NO)
Not:
if(isAwesome ==YES)// Never do this.
@property (assign, getter=isEditable)BOOLeditable;
20.单例
Singleton objects SHOULD use a thread-safe pattern for creating their shared instance.
+ (instancetype)sharedInstance {
staticidsharedInstance =nil;
staticdispatch_once_tonceToken;
dispatch_once(&onceToken, ^{
sharedInstance = [[[selfclass]alloc]init];
});
returnsharedInstance;
}
21.imports
If there is more than one import statement, statements MUST be groupedtogether. Groups MAY be commented.
Note: For modules use the@importsyntax.
// Frameworks
@import QuartzCore;
// Models
#import"NYTUser.h"
// Views
#import"NYTButton.h"
#import"NYTUserView.h"
22.协议
In adelegate or data source protocol, the first parameter to each method SHOULD be the object sending the message.
This helps disambiguate in cases when an object is the delegate for multiple similarly-typed objects, and it helps clarify intent to readers of a class implementing these delegate methods.
For example:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath;
Not:
- (void)didSelectTableRowAtIndexPath:(NSIndexPath*)indexPath;
