Obj-，当'self'未设置为'[（super或self）init ...]'的结果时使用的实例变量 [英] Obj-, Instance variable used while 'self' is not set to the result of '[(super or self) init...]'

问题描述

   - （id）我已经对这个问题提出了类似的问题， initWithKeyPadType：（int）value 
 {
 [self setKeyPadType：value]; 
 self = [self init]; 
 if（self！= nil）
 {
 //self.intKeyPadType = value; 
 
} 
 return self; 
} 
 
  - （id）init {
 
 NSNumberFormatter * formatter = [[[NSNumberFormatter alloc] init] 
 autorelease] 
 decimalSymbol = [formatter decimalSeparator]; 
 .... 
  

警告来自上面的行 'self'未设置为'[（super或self）init ...]'的结果时使用的实例变量

解决方案

你想做什么是技术上OK，但在某些阶段你需要调用 [super init] 。如果你的类的 init 方法使用了很多其他 initWith ... 方法的常见初始化， code> [super init] 。此外，在尝试使用实例变量之前，始终确保类已经 init '。

   - （id）initWithKeyPadType：（int）value 
 {
 self = [self init]; // invoke common initialisation 
 if（self！= nil）
 {
 [self setKeyPadType：value]; 
} 
 return self; 
} 
 
  - （id）init 
 {
 self = [super init] // invoke NSObject initialisation（or whoever superclass is）
 if（！self）return nil; 
 
 NSNumberFormatter * formatter = [[[NSNumberFormatter alloc] init] 
 autorelease]; 
 decimalSymbol = [formatter decimalSeparator]; 
 
 ... 
  

I asked a similar question to this already, but I still can't see the problem?

-(id)initWithKeyPadType: (int)value
{
    [self setKeyPadType:value];
    self = [self init];
    if( self != nil )
    {
        //self.intKeyPadType = value;

    }
    return self;
}

- (id)init {

    NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] 
                                                              autorelease];
    decimalSymbol = [formatter decimalSeparator];
....

The warning comes from the line above Instance variable used while 'self' is not set to the result of '[(super or self) init...]'

解决方案

What you are trying to do is technically OK, but at some stage you need to invoke [super init]. If your class's init method does a lot of common initialisation that other initWith... methods utilise, then put your [super init] in there. Also, always make sure that the class has been init'd before trying to play around with instance variables.

- (id) initWithKeyPadType: (int)value
{
    self = [self init]; // invoke common initialisation
    if( self != nil )
    {
        [self setKeyPadType:value];
    }
    return self;
}

- (id) init
{
    self = [super init]; // invoke NSObject initialisation (or whoever superclass is)
    if (!self) return nil;

    NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] 
                                                          autorelease];
    decimalSymbol = [formatter decimalSeparator];

    ...

这篇关于Obj-，当'self'未设置为'[（super或self）init ...]'的结果时使用的实例变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！