我知道不久前我问过类似的问题,但我仍然有点不确定。同样的事情在很多地方都发生过。
当“self”未设置为“[(super or self) init...]”的结果时使用的实例变量
A
- (id)initWithCoder:(NSCoder *)decoder {
if (![super init]) return nil;
red = [decoder decodeFloatForKey:kRedKey]; //occurs here
green = [decoder decodeFloatForKey:kGreenKey];
blue = [decoder decodeFloatForKey:kBlueKey];
return self;
}
B
- (id)initWithFrame:(CGRect)frame title:(NSString*)str sideUp:(BOOL)up{
if(![super initWithFrame:frame]) return nil;
int y;
UIImage *img;
if(up){
img = [UIImage imageNamedTK:@"TapkuLibrary.bundle/Images/graph/popup"];
y = 5;
}else{
img = [UIImage imageNamedTK:@"TapkuLibrary.bundle/Images/graph/popdown"];
y = 14;
}
background = [[UIImageView alloc] initWithImage:img]; // occurs here
C
- (id) initWithFrame:(CGRect)frame {
if(![super initWithFrame:frame]) return nil;
UILabel *titleBackground = [[[UILabel alloc] initWithFrame:
CGRectMake(0, 0, 480, 40)] autorelease];
titleBackground.backgroundColor = [UIColor whiteColor];
[self addSubview:titleBackground];
titleLabel = [[UILabel alloc] initWithFrame:CGRectZero]; // occurs here
对于 A 块,这是正确的吗
self = [self init];
if( self != nil )
{
还有B&C
- (id) initWithFrame:(CGRect)frame {
super = [super initWithFrame:frame]
if(super != nil)
{