Kristopher Micinski wrote: > I guess the bigger problem that in Android static data members cannot > be statically checked to be "alive". By this I mean: you should try > to get as much static checking as possible, and if you're using > statics you don't have any ability to properly check this. > > Moreover, in Android it's a fact of life that your app will die and > restart. You can really only use statics for "caching" type purposes, > but working with them in a safe way quickly becomes extremely > complicated. Instead of doing this, you can typically replace > singletons with some Android specific utility (a Service or > ContentProvider, say..) that allows you to implement the "singleton" > type pattern. > > This really *is* a pretty frequent problem when people get UI elements > stuck into static variables and then users rotate the screen :-) > > Kris > > On Thu, Mar 14, 2013 at 7:11 PM, Mark Murphy > <[email protected]<javascript:>> > wrote: > > On Thu, Mar 14, 2013 at 7:00 PM, user123 <[email protected]<javascript:>> > wrote: > >> What is the problem with singleton? > > > > > http://stackoverflow.com/questions/7026507/why-are-static-variables-considered-evil > > > > http://stackoverflow.com/questions/137975/what-is-so-bad-about-singletons > > > > And, since they don't seem to emphasize the point quite enough for my > > taste: static data members are, by definition, memory leaks. How *bad* > > of a memory leak they are depends on what they are and how they are > > used. > > > > Like many programming techniques, singletons can be used as a scalpel > > or a sledgehammer. The general advice against singletons is because > > most people reading that advice are inexperienced and are likely to do > > damage with either a scalpel or a sledgehammer. > > > > On the whole, AFAICT, tolerance for singletons decreases with > > increased production Java development experience, based on the > > conversations that I have had on the topic over the past few years. > > I've been using Java professionally for fourteen years.
The biggest problem I have with singletons is that everyone for some god-awful reason insists on lazily instantiating them. Why? Lazy instantiation is lazy. What's wrong with non-lazy instantiation? Then you can use a 'final' reference to the singleton instance that exists without effort or overhead. -- Lew -- -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en --- You received this message because you are subscribed to the Google Groups "Android Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
