iOS应用开发最佳实践:编写高质量的Objective-C代码
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点标记语法 属性和幂等方法(多次调用和一次调用返回的结果相同)使用点标记语法访问,其他的情况使用方括号标记语法。 良好的风格 : view.backgroundColor = [UIColor orangeColor]; [UIApplication sha
![](http://www.cocoachina.com/cms/uploads/allimg/131129/4196_131129153207_1.jpg)
void *ptr = &value + 10 * 3;
NewType a = (NewType)b;
for (int i = 0; i < 10; i++) {
doCoolThings();
}
数组和字典类型的字面值的方括号两边各放置一个空格。
NSArray *theShit = @[ @1, @2, @3 ];
NSArray *theShit = @[
@"Got some long string objects in here.",
[AndSomeModelObjects too],
@"Moar strings."
];
NSDictionary *keyedShit = @{
@"this.key": @"corresponds to this value",
@"otherKey": @"remoteData.payload",
@"some": @"more",
@"JSON": @"keys",
@"and": @"stuff",
};
![](http://www.cocoachina.com/cms/uploads/allimg/131129/4196_131129145958_1.png)
if (user.isHappy) {
//Do something
}
else {
//Do something else
}
if (!error) {
return success;
}
if (!error)
return success;
NSError *error;
if (![self trySomethingWithError:&error]) {
// Handle Error
}
NSError *error;
[self trySomethingWithError:&error];
if (error) {
// Handle Error
}
@interface CustomModelViewController : TTViewController <
TTModelDelegate,
TTURLRequestDelegate
> {
[object/class thing+condition];
[object/class thing+input:input];
[object/class thing+identifer:input];
realPath = [path stringByExpandingTildeInPath];
fullString = [string stringByAppendingString:@"Extra Text"];
object = [array objectAtIndex:3];
// 类方法
newString = [NSString stringWithFormat:@"%f",1.5];
newArray = [NSArray arrayWithObject:newString];
recipients = [email recipientsSortedByLastName];
newEmail = [CDCEmail emailWithSubjectLine:@"Extra Text"];
emails = [mailbox messagesReceivedAfterDate:yesterdayDate];
[object adjective+thing];
[object adjective+thing+condition];
[object adjective+thing+input:input];
capitalized = [name capitalizedString];
rate = [number floatValue];
newString = [string decomposedStringWithCanonicalMapping];
subarray = [array subarrayWithRange:segment];
-sortInfo // 是返回排序结果还是给info做排序
-refreshTimer // 返回一个用于刷新的定时器还是刷新定时器
-update // 更新什么,如何更新
-currentSortInfo // "current" 清楚地修饰了名词SortInfo
-refreshDefaultTimer // refresh是一个动词。
-updateMenuItemTitle // 一个正在发生的动作
color = [NSColor colorWithCalibratedHue: 0.10
saturation: 0.82
brightness: 0.89
alpha: 1.00];
//MyViewController.h文件
@interface MyViewController : UIViewController<
UITalbeViewDataSource,
UITableViewDelegate> {
@private:
UITableView *_myTableView; // 私有实例变量
}
// 内部使用的属性
@property (nonatomic,strong) NSNumber *variableUsedInternally;
- (void)sortName; // 只用于内部使用的方法
@end
//MyViewController.m文件使用类扩展
@interface MyViewController()<
UITalbeViewDataSource,
UITableViewDelegate> {
UITableView *_myTableView;
// 外部需要访问的实例变量声明为属性,不需要外部访问的声明为实例变量
NSNumber * variableUsedInternally;
}
// 从Xcode4.3开始,可以不写方法的前置声明,Interface Builder和Storyboard仍然可以找到方法的定义
@end
- (void) setTitle: (NSString *) aTitle;
- (void) setName: (NSString *) newName;
- (id) keyForOption: (CDCOption *) anOption
- (NSArray *) emailsForMailbox: (CDCMailbox *) theMailbox;
- (CDCEmail *) emailForRecipients: (NSArray *) theRecipients;
for (i = 0; i < count; i++) {
oneObject = [allObjects objectAtIndex: i];
NSLog (@"oneObject: %@", oneObject);
}
NSEnumerator *e = [allObjects objectEnumerator];
id item;
while (item = [e nextObject])
NSLog (@"item: %@", item);
@interface RNCSection: NSObject
@property (nonatomic) NSString *headline;
@end
@interface RNCSection : NSObject {
NSString *headline;
}
@interface RNCSection : NSObject {
NSString *headline;
}
@property (nonatomic) NSString *headline;
@end
@interface RNCSection: NSObject
@property (nonatomic) NSString *headline;
@end
NSString *accountName;
NSMutableArray *mailboxes;
NSArray *defaultHeaders;
BOOL userInputWasUpdated;
NSString *accountNameString;
NSMutableArray *mailboxArray;
NSArray *defaultHeadersArray;
BOOL userInputWasUpdatedBOOL;
NSImage *previewPaneImage;
NSProgressIndicator *uploadIndicator;
NSFontManager *fontManager; // 基于类名命名
NSDictionary * keyedAccountNames;
NSDictionary * messageDictionary;
NSIndexSet * selectedMailboxesIndexSet;
/**
* The maximum size of a download that is allowed.
*
* If a response reports a content length greater than the max * will be cancelled. This is helpful for preventing excessive memory usage.
* Setting this to zero will allow all downloads regardless of size.
*
* @default 150000 bytes
*/
@property (nonatomic) NSUInteger maxContentLength;
- (instancetype)init {
self = [super init]; // or call the designated initalizer
if (self) {
// Custom initialization
}
return self;
}
NSArray *names = @[@"Brian", @"Matt", @"Chris", @"Alex", @"Steve", @"Paul"];
NSDictionary *productManagers = @{@"iPhone" : @"Kate", @"iPad" : @"Kamal", @"Mobile Web" : @"Bill"};
NSNumber *shouldUseLiterals = @YES;
NSNumber *buildingZIPCode = @10018;
NSArray *names = [NSArray arrayWithObjects:@"Brian", @"Matt", @"Chris", @"Alex", @"Steve", @"Paul", nil];
NSDictionary *productManagers = [NSDictionary dictionaryWithObjectsAndKeys: @"Kate", @"iPhone", @"Kamal", @"iPad", @"Bill", @"Mobile Web", nil];
NSNumber *shouldUseLiterals = [NSNumber numberWithBool:YES];
NSNumber *buildingZIPCode = [NSNumber numberWithInteger:10018];
CGRect frame = self.view.frame;
CGFloat x = CGRectGetMinX(frame);
CGFloat y = CGRectGetMinY(frame);
CGFloat width = CGRectGetWidth(frame);
CGFloat height = CGRectGetHeight(frame);
CGRect frame = self.view.frame;
CGFloat x = frame.origin.x;
CGFloat y = frame.origin.y;
CGFloat width = frame.size.width;
CGFloat height = frame.size.height;
static NSString * const RNCAboutViewControllerCompanyName = @"The New York Times Company";
static const CGFloat RNCImageThumbnailHeight = 50.0;
#define CompanyName @"The New York Times Company"
#define thumbnailHeight 2
#ifndef NS_ENUM
#define NS_ENUM(_type, _name) enum _name : _type _name; enum _name : _type
#endif
typedef NS_ENUM(NSInteger, RNCAdRequestState) {
RNCAdRequestStateInactive,
RNCAdRequestStateLoading
};
@interface NYTAdvertisement ()
@property (nonatomic, strong) GADBannerView *googleAdView;
@property (nonatomic, strong) ADBannerView *iAdView;
@property (nonatomic, strong) UIWebView *adXWebView;
@end
if (!someObject) {
}
if (someObject == nil) {
}
if (isAwesome)
if (![someObject boolValue])
if ([someObject boolValue] == NO)
if (isAwesome == YES) // Never do this.
+ (instancetype)sharedInstance {
static id sharedInstance = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedInstance = [[self alloc] init];
});
return sharedInstance;
}