Weakreference get() method how safe is it? (Android, asynctask)

Question

I am making an Android mobile app. I have a WeakReference to my Activity in the AsyncTask to ensure that it can be garbage collected.

When onPostExecute() g

Answer 1

I think it's NOT safe. I get a NPE at activity.msgWebView.setVisibility(View.GONE); inside Handler.

```java

private static class HttpStatusHandler extends Handler {

    private WeakReference<MessageWebViewActivity> activityWeakReference;

    public HttpStatusHandler(WeakReference<MessageWebViewActivity> activityWeakReference) {
        this.activityWeakReference = activityWeakReference;
    }

    @Override
    public void handleMessage(Message msg) {
        MessageWebViewActivity activity = activityWeakReference.get();
        if (activity != null) {
            if (msg.what == MSG_URL_OK) {
                activity.loadUrl(activity.url);
            } else if (msg.what == MSG_URL_ERROR) {
                activity.msgWebView.setVisibility(View.GONE);
                activity.clPageError.setVisibility(View.VISIBLE);
                activity.progressbarLayout.setVisibility(View.GONE);
            }

        }
    }
}

```

Answer 2

It's safe!
As soon as you assign the result of get() to a variable, you have a strong reference again which blocks gargbage collection for this object as long as the new reference exists.
Of course, after this assignment you need to check if activity is null.