Static context in App class - memory leak

Question

To be able to get app context anywhere in my app, I created App class like this:

public class App extends Application
{
    private static Context mContext;

    public static Context getContext()
    {
        return mContext;
    }


    @Override
    public void onCreate()
    {
        super.onCreate();
        mContext = this

    }
}

It works and also it's used in many places in my app where I need to use context (for example, to load resources) and I am not able to inject any other context to use.

However, Android Studio throws warning this approach (static context fields) causes memory leak.

Do you have any idea how to avoid static context field, but get similar functionality?

Related [“Warning: Do not place Android context classes in static fields; this is a memory leak (and also breaks Instant Run)”](https://stackoverflow.com/questions/40094020/warning-do-not-place-android-context-classes-in-static-fields-this-is-a-memor) — AskNilesh, Oct 17 '18 at 06:37
I found sugeestion to use `App` insted of `Context`, no warning anymore, but is that actually valid solution? — user1209216, Oct 17 '18 at 06:40

score 4 · Answer 1 · answered Oct 17 '18 at 06:43

4

Never place static Context in your application since it will cause unexcepted memory leaks, however if you still want to use static Context in your application you can wrap the context in a WeakReference so change

private static Context mContext;

to

private static WeakReference<Context> mContext;

and on create change it to

mContext = new WeakReference<>(Context);

and finally get the Context using

public static Context getContext() {
    return mContext.get();
}

if you want to research more about WeakRef use the link below, https://developer.android.com/reference/java/lang/ref/WeakReference

answered Oct 17 '18 at 06:43

SamHoque

2,978
2
13
43

What is better in my case, use `WeakReference` or change `Context` data type to `App`? Both soultions causes stop warnings. – user1209216 Oct 17 '18 at 07:00
App will still cause leaks, How ever you can also wrap the App inside WeakRefernce to stop it, Do what you like most. – SamHoque Oct 17 '18 at 07:04
I think I will wrap `Context` with `WeakReference`, I hope it helps. Actually, my app sometimes hangs on splash screen, I suspect because of garbage collection and it could be caused by memory leaks like this, now I'm trying to figure out any possible reasons – user1209216 Oct 17 '18 at 07:17

milad salimi · Answer 2 · 2018-10-17T07:12:53.623

1

Its not necessary use static for access context ,you can use get context ,get application context or get activity any where. as far as possible you should avoid from passing context. like this in fragments :DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(getContext(), layoutManager.getOrientation());

and in this (if the OP wanted to use Context in where the class does not host a Context method) case you can pass context without define it as a static. for example :

public class DashboardWalletSpinnerAdapter extends ArrayAdapter<Wallet> {

private LayoutInflater mLayoutInflater;
private static final int CLOSE = 0;
private static final int OPEN = 1;

public DashboardWalletSpinnerAdapter(Context mContext, List<Wallet> walletList) {

    super(mContext, R.layout.spinneritemclose_dashbaord, walletList);
    mLayoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

edited Oct 17 '18 at 07:12

answered Oct 17 '18 at 06:43

milad salimi

1,580
2
12
31

This is not very accurate, What if the OP wanted to use Context in where the class does not host a Context method? – SamHoque Oct 17 '18 at 06:47
Yes, sometimes I want to get context outside activity/fragment etc. – user1209216 Oct 17 '18 at 06:48
@Rab , you can pass context without define it as a static – milad salimi Oct 17 '18 at 07:13

Static context in App class - memory leak

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