For how long do static objects preserve their instances on Android?

Question

So I used a bit of a hack to preserve the state of a WebView in a Fragment.

private enum WebViewStateHolder
{
    INSTANCE;

    private Bundle bundle;

    public void saveWebViewState(WebView webView)
    {
        bundle = new Bundle();
        webView.saveState(bundle);
    }

    public Bundle getBundle()
    {
        return bundle;
    }
}

Then

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState)
{
    View rootView = inflater.inflate(R.layout.activity_example, container, false);
    ButterKnife.inject(this, rootView);
    ...
    if(WebViewStateHolder.INSTANCE.getBundle() == null)
    {
        webView.loadUrl("file:///android_asset/index2.html");
    }
    else
    {
        webView.restoreState(WebViewStateHolder.INSTANCE.getBundle());
    }
    return rootView;
}

And

@Override
public void onPause()
{
    ...
    WebViewStateHolder.INSTANCE.saveWebViewState(webView);
    super.onPause();
}

So basically I save out the bundle on pause, then when the Fragment creates a view and this is not null, I load it back. It works perfectly okay, actually. However, if I say

getActivity().finish();

The WebView loads its data back from the bundle itself, still remembering the history of where it was.

This doesn't seem too reliable, and while this is a result of a test, I was still surprised that this happened.

When does a static object lose its data on Android? How long do these instances exist? Does Android get rid of them over time?

possible duplicate of [Android static object lifecycle (Application act crazy)](http://stackoverflow.com/questions/1944369/android-static-object-lifecycle-application-act-crazy) — , Nov 28 '14 at 16:29
On a sidenote, I've just noticed the `onCreateView()`'s third parameter is the save instance state, meaning I don't even have to save it out into a static holder. Oh well. — EpicPandaForce, Nov 29 '14 at 14:41

score 1 · Accepted Answer · answered Nov 28 '14 at 16:54

1

The static variable will exist until your process is terminated.

answered Nov 28 '14 at 16:54

CommonsWare

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score 0 · Answer 2 · answered Nov 28 '14 at 16:18

0

The static variable will exists until you class will be unloaded, so for example when you kill your activity or it will be killed because of memory issues

answered Nov 28 '14 at 16:18

MineConsulting SRL

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1

Activity classes are not unloaded. Activities are not killed because of memory issues. – CommonsWare Nov 28 '14 at 16:53

For how long do static objects preserve their instances on Android?

2 Answers2

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