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Bypassing onCreate() on up navigation in Android Activity.


You may provide one back button in Android Activity's Toolbar at Top left corner. Default back button is enough. But in recent times this icon is provided for good design looking purpose only.

So simple design looking code shouldn't recreate the previous Activity right?

But in Android up navigation from one Activity to previous Activity will recreate the previous Activity. So the previous Activity's onCreate() method will get called. But sometime we don't want to recreate the previous Activity. Just resume is enough. So we may avoid unwanted coding execution which already executed.

But did you noticed that bottom default back button will not recreate the Activity. It will just resume the Activity which is in paused state already.

So we may use this default back button's code in up navigation also. Then while tapping up navigation icon also our previous Activity will resume instead of recreate.

Here is the code sample 
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case android.R.id.home:
                //To resume previous activity on up navigation this simple code is enough.
                //By this we can simply resume previous activity.
                onBackPressed();
                break;
        }
        return true;
    }
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