我想知道初始化单例类成员的最佳位置在哪里。
我正在使用 Apple 基本指南单例实现。您能指出 init 发生在哪一行吗?代码如下:
static MyGizmoClass *sharedGizmoManager = nil;
+ (MyGizmoClass*)sharedManager
{
@synchronized(self) {
if (sharedGizmoManager == nil) {
[[self alloc] init]; // assignment not done here
}
}
return sharedGizmoManager;
}
+ (id)allocWithZone:(NSZone *)zone
{
@synchronized(self) {
if (sharedGizmoManager == nil) {
sharedGizmoManager = [super allocWithZone:zone];
return sharedGizmoManager; // assignment and return on first allocation
}
}
return nil; //on subsequent allocation attempts return nil
}
- (id)copyWithZone:(NSZone *)zone
{
return self;
}
- (id)retain
{
return self;
}
- (unsigned)retainCount
{
return UINT_MAX; //denotes an object that cannot be released
}
- (void)release
{
//do nothing
}
- (id)autorelease
{
return self;
}
最佳答案
就像通常的类一样 - 将其添加到 block 上方:
-(id)init {
if (self = [super init]) {
// do init here
}
return self;
}
第一次访问单例时会调用它。
关于iphone - Cocoa - 单例对象 : Where to initialize member variables?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/1314681/