Deleting crimes from CrimePagerActivity instead of CrimeFragment

Android Programming (3rd Edition) 14. SQLite Databases
1

One can also delete crimes from CrimePagerActivity, which is slightly different, since there are several pages open. I came up with this, because I had some problems changing the menu in CrimeFragment. First add the remove icon and add code to fragment_crime_list.xml. We don’t need a new menu but just show or hide, what we need to when adding or deleting a crime.

        .....
   <item
    android:id="@+id/remove_crime"
    android:icon="@drawable/ic_menu_remove"
    android:title="@string/remove_crime"
    app:showAsAction="ifRoom|withText" />
    .....

Then add this code in CrimePagerActivity at the end.

    // challenge 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.fragment_crime_list, menu);
        menu.findItem(R.id.remove_crime);
        menu.removeItem(R.id.new_crime);
        return super.onCreateOptionsMenu(menu);
    }

In CrimeListFragment add a line of code at the end of the onCreateOptionsMenu

  ..........
        subtitleItem.setTitle(R.string.show_subtitle);
    }

    // challenge 
    menu.removeItem(R.id.remove_crime);
}

In CrimePagerActivity create these two variables.

   private Crime removeCrime;
    private int rCrime = -1;

To get the correct crime, change the getItem function.

@Override 
public Fragment getItem(int position) {
    Crime crime = mCrimes.get(position);

        // challenge 
        if (rCrime == -1) {
            rCrime = position;
            removeCrime = crime;
        }
        return CrimeFragment.newInstance(crime.getId());
    }

Then add the onOptionsItemsSelected function after the onCreateOptionsMenu. See the comments for differences to CrimeFragment.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
    case R.id.remove_crime:

        // Delete from CrimeLab
        CrimeLab crimeLab = CrimeLab
                .get(getApplicationContext());// we have to use getApplicationContext() here.
        crimeLab.deleteCrime(removeCrime);

        // Make changes in CrimeListFragment
        Intent intent = new Intent(this,
                CrimeListActivity.class); // intent has to refer to this
        startActivity(intent);
        finish();

        return true;
    default:
        return super.onOptionsItemSelected(item);
  }
}

Finally add a delete function in CrimeLab.

// challenge
public void deleteCrime(Crime crime) {
    String uuidString = crime.getId().toString();

    mDatabase.delete(CrimeDbSchema.CrimeTable.NAME,
            CrimeDbSchema.CrimeTable.Cols.UUID + " = ?",
            new String[] { uuidString });
}