Android: In tabbed app, textView output is not consistant with LogCat

Question

In my app which has tabbed activity, I am sending a simple message to textView and logcat (message indicating which tab I am selecting).

However, textView shows correct string but logcat shows different one.

Steps to reproduce this problem are very simple:

1. Start a new Android Studio project (My Android Studio version: 1.5.1)

2. Give any application name (e.g. MyApplication)

3. Keep only "Phone and Tablet" selected

4. Select "Tabbed Activity"

5. Choose Navigation Style "Action Bar Tabs (with View Pager)"

6. Click finish

This will generate and build project. If we run this application it will show string "Hello World from section: 1" on first tab, "Hello World from section: 2" on second and "Hello World from section: 3" on third tab.

Now, go in MainActivity.java and in method onCreateView (of class PlaceholderFragment) just below this line (where it send string to textView),

textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));

add this line

Log.i("onCreateView", "From tab number: " + getArguments().getInt(ARG_SECTION_NUMBER));

Expected behaviour:

textView and logcat both should display same message as we tap on tabs.

Actual behaviour:

textView shows correct strings. However in logcat, tab numbers shown are incorrect and hence not in consistent with textView output.

This is indeed weird and height of all is, instead of this when I tried forming string on my own and passing it to textView and LogCat

        String strMessage = "Msg from tab number: " + getArguments().getInt(ARG_SECTION_NUMBER);
        textView.setText (strMessage);
        Log.i("onCreateView", strMessage);

It still has SAME behaviour i.e. shows correct strings in textView for relevant tabs but Logcat shows completely different tab numbers. Same string I am sending but only number changes ???

Answer 1

I found root cause of this on my own. Looks like textView.setText called in onCreateView sets the text value and it never changes afterwards. I wanted to find out which tab currently is active or visible so that I could update its contents. And I was under wrong impression that onCreateView gets called when tab is visible. Finally I found this answer which solved my problem.