Interface and API Design in iOS (part 1)

This is the 22nd day of my participation in the August More Text Challenge

Use prefixes to avoid naming conflicts

Prefixes the name of a company, application, or association that is related to both
The usual prefix should be three letters (Apple keeps the two-letter prefix).
Always prefix the classification
Write tripartite library, must add prefix, use other tripartite library, should add your prefix in front of other tripartite library, avoid others integration into the conflict with other tripartite library

For example: your third party library uses YYLibrary library, your project library is called QQLibrary, after modification should be QQYYLibrary

Clear and coordinated naming

Name a method for considerations
- If the method return value is newly created, the first word of the method name should be the type of the return value, unless preceded by a modifier
- You should place the parameter type noun before the parameter
- If a method performs an operation on the current object, it should include a verb; If you need parameters to perform an operation, you should follow the verb with one or more nouns
- Don’t use short names like STR, use full names like string
- BOOLThe value property should be addedisPrefix if a method returns a value that is not its propertyBOOLValue, then should be processed according to its function, selectionhasorisWhen the prefix
- willgetThis prefix is reserved for methods that store the return value by “output parameters.
Naming of classes and protocols

Prefix the names of classes and protocols
Private methods are prefixed
- Private methods are prefixed to facilitate debugging and to distinguish them from public apis
- Do not prefix private methods with an underscore; the underscore is reserved by Apple

Use immutable objects whenever possible

When using an attribute, you can declare it as”readonly“(Default:readwrite)
For example, if a property is passed in through an initialization method, the value of a property that is declared separately can be declared asreadonly

#import <Foundation/Foundation.h>
@interface Phone : NSObject
@property (nonatomic,copy,readonly) NSString *name;
@property (nonatomic,assign,readonly) NSInteger price;

- (instancetype)initWithName:(NSString *)name withPrice:(NSInteger)price;
@end

Copy the code

If you want to modify data without letting outsiders know, you can usually set it toreadwrite

#import "Phone.h"
// redeclare the classification
@interface Phone()
@property (nonatomic,copy,readwrite) NSString *name;
@property (nonatomic,assign,readwrite) NSInteger price;
@end

@implementation Phone
- (instancetype)initWithName:(NSString *)name withPrice:(NSInteger)price{
    self = [super init];
    if (self) {
        
        _name = [name copy];
        _price = price;
    }
    return self;
}
@end
Copy the code

Try not to put variablearray,set,dictionaryAs public attributes, you should provide methods to modify mutable attributes in an object

Why can’t you just define phoneArray as mutable and control it with phoneArray? For example, Phone objects may need to perform other operations when adding or deleting phoneArray. If you modify the internal phoneArray for storage directly from the bottom layer, data inconsistency may occur among Phone objects if you modify phoneArray without Phone objects’ knowledge

#import <Foundation/Foundation.h>
@interface Phone : NSObject
@property (nonatomic,copy,readonly) NSString *name;
@property (nonatomic,assign,readonly) NSInteger price;
@property (nonatomic,strong,readonly) NSArray *phoneArray;

- (instancetype)initWithName:(NSString *)name withPrice:(NSInteger)price;
- (void)addPhone:(Phone *)phone;
- (void)removePhone:(Phone *)phone;
@end

#import "Phone.h"
@interface Phone()
@property (nonatomic,copy,readwrite) NSString *name;
@property (nonatomic,assign,readwrite) NSInteger price;
@property (nonatomic,strong,readwrite) NSMutableArray *savePhoneArray;
@end

@implementation Phone

- (instancetype)initWithName:(NSString *)name withPrice:(NSInteger)price{
    self = [super init];
    if (self) {
        _name = [name copy];
        _price = price;
        _savePhoneArray = [[NSMutableArray alloc]init];
    }
    return self;
}
- (instancetype)init{
    return [self initWithName:@"iPhone" withPrice:999];
}
-(NSMutableArray *)savePhoneArray{
    if (_savePhoneArray == nil) {
        _savePhoneArray = [NSMutableArray new];
    }
    return _savePhoneArray;
}

- (void)addPhone:(Phone *)phone{
    [self.savePhoneArray addObject:phone];
}
- (NSArray *)phoneArray{
    return [self.savePhoneArray copy];
}
- (void)removePhone:(Phone *)phone{
    [self.savePhoneArray removeObject:phone];
}
@end
Copy the code

Knowledge about iOS interface and API design