好的记忆课清理习惯？

Question

I've recently been watching videos from google android devs about the importance of removing reference to objects when your done with them... I've implemented just a simple cleanup method. Will that actually work?

For example I do a lot of animation on views in my app. to make things cleaner I do my animations for a activity in different class. I pass a reference of the activity to the tweenanimation class.

public void onStart() {
    tweens = new TweenUm(this);
}

and in my onStop I do...

public void onStop() {
    tweens.cleanup();
    tweens = null;
    super.onStop();
}

my cleanup method looks something like...

public void cleanup() {
    mainAct = null;
    fab = null;
    fabcrad=null;
    searchFor = null;
}

mainact is the activity I passed in, plus other views i want to remove ref to.

Will this do any good?

Answer 1

It is not necessary to add a method cleanup .

Because you are nulling the reference to the object tweens , if no other references are mantained in memory, tweens and all internal objects referenced only by tweens (mainAct, fab, fabcrad, searchFor) will be freed from memory by garbage collector.

Use a cleanup method only to close resources (like files, sockets and so on).

Note: while nulling tweens is important creating (and calling) cleanup is not a good choice, infact there are two possibilities:

• no other references to tweens exists, so nulling internal references is not necessary
• other references to tweens exists, in this case you probably will break internal state of tweens coming to a not valid state.

So generally if you don't need to close external opened resources it is not a good practice to use a cleanup method.