CODEWITHSUNDEEP
androidandroid-linearlayout
artem
artem

Reputation: 16777

getChildAt returns null

I have a LinearLayout with programmatically added children:

for (int i = 0; i < answers.size(); i++) {
            final AnswerView answerView = new AnswerView(getContext(), i);
            addView(answerView);
}

Then I'm trying to access random child:

private void updateOpenAnswer() {
        new AsyncTask<Void, Void, Integer>() {

            @Override
            protected Integer doInBackground(Void... voids) {
                return API.getOpenAnswer();
            }

            @Override
            protected void onPostExecute(Integer answerIndex) {
                super.onPostExecute(answerIndex);

                Log.i(TAG, "Child count: " + getChildCount());

                if (answerIndex != -1) {
                    Log.i(TAG, "Open answer: " + answerIndex);
                    final AnswerView answerView = (AnswerView) getChildAt(answerIndex);
                    if (answerView != null) {
                        answerView.setAnswerOpen(true);
                    } else {
                        Log.e(TAG, "Null at " + answerIndex);
                    }
                }
            }
        }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    }

updateOpenAnswer is called once in a second in runnable. And for some calls of updateOpenAnswer getChildAt returns null and getChildCount returns 0! For example, null for 2 and 3, and not null for 0,1,4,5. The views at 2 and 3 really exist and I see them. Why it returns null?

Upvotes: 0

Views: 2052

Answers (1)

Simon Dorociak
Simon Dorociak

Reputation: 33505

final AnswerView answerView = new AnswerView(getContext(), i);

Most likely problem is getContext() that returns null. Try to change it to

YourActivity.this // this also returns Context

And now it should works.

Update:

Don't remember that getChildAt() will return a view only for the positions which are displaying. So if you are scrolling and want to get child that is not "in View" null will be returned.

Upvotes: 1

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