Missing initialization of mSubtitleVisible

Android Programming (3rd Edition) 13. The Toolbar
1

At the end of page 264, when I tried to run CriminalIntent it crashed.

logcat says I’m getting a NullPointerException at line 69 of CrimeListFragment.java

69:

if (mSubtitleVisible) {
        subtitleItem.setTitle(R.string.hide_subtitle);
    } else {
        subtitleItem.setTitle(R.string.show_subtitle);
    }

So mSubtitleVisible is null.

To resolve this, I added a conditional initialization in the onCreateView method after the mCrimeRecyclerView is set:

        if (mSubtitleVisible == null){
        mSubtitleVisible = false;
    }

Not sure if this is the approach we’d need to take or how else we should be initializing this.

2

Hi mattjn,

Please paste the whole method onCreateOptionsMenu() method in the CrimeListFragment.java.
I guess the issue may be due to the the null value of subtitleItem, not mSubtitleVisible. mSubtitleVisible is a boolean value and it cannot be a null value.