Objective-C约定防止"本地声明隐藏实例变量"警告

Question

我使用以下代码...

-(id) initWithVariableName:(NSString*)variableName withComparisonValue:(NSString*)comparisonValue {

    // super init
    self = [super init];
    if (!self) return nil;

    // set instance variables
    self.mustExist = NO;
    self.reverseCondition = NO;
    self.regularExpression = NO;
    self.variableName = variableName; // generates warning
    self.comparisonValue = comparisonValue; // generates warning

    return self;
}

这产生了以下两个警告......

• 'variableName'的本地声明隐藏了实例变量
• 'comparisonValue'的本地声明隐藏了实例变量

处理这些警告是否有共同或公认的惯例？

我知道只是告诉用户他们应该在引用类成员时指定一个实例,但它很烦人.

Answer 1

我认为这是一个相当古老的问题,并且已经接受了答案,但我有一个更好的解决方案及其代码约定.

该约定规定您使用下划线(_varName)和公共(如属性)为私有变量添加前缀,仅使用名称.

有了这个,你就可以在函数中调用相同的变量名.

例:

ExampleClass.h

@interface ExampleClass : NSObject
{
    NSString *_varName; //this is not required if you create a property
}

@property (nonatomic, retain) NSString *varName;

- (void)someMethodWithVarName:(NSString *)varName;

@end

ExampleClass.m

#import "ExampleClass.h"

@implementation ExampleClass

@synthesize varName = _varName; //if you don't declare the _varName in the header file, Objective-C does it for you.

- (id)init
{
    self = [super init];
    if (self) {
        // Initialization code here.
    }

    return self;
}

- (void)someMethodWithVarName:(NSString *)varName
{
    _varName = varName; //just for example purpose
}

@end

Answer 2

不幸的是,没有没有"好"的方法来防止这个错误.常见的模式是使用一个稍微愚蠢的参数名称

-(id) initWithVariableName:(NSString*)theVariableName 
       withComparisonValue:(NSString*)theComparisonValue {
    self.variableName = theVariableName;
    self.comparisonValue = theComparisonValue;

    return self;
}