I’ve been working on an Android app that uses a navigation drawer, and uses fragments for each item in the drawer that you tap on. One of the items in the nav drawer is a “Preferences” item, so when I tap on that item, I run the following code from my nav drawer code:
Fragment prefsFragment = new PreferencesFragment(); FragmentManager fragmentManager = getFragmentManager(); fragmentManager.beginTransaction().replace(R.id.content_frame, prefsFragment).commit();
What this does is create a new instance of my
PreferencesFragment, and then puts that fragment into what I call the
content_frame refers to a
FrameLayout that I’ve defined in my activity_main.xml layout file. This fragment basically replaces whatever else was in that
FrameLayout before this call. I believe this is the correct approach, at least with the navigation drawer code that I’m using.
My main layout file
For the record, my activity_main.xml file currently looks like this:
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/drawer_layout" android:layout_width="match_parent" android:layout_height="match_parent"> <FrameLayout android:id="@+id/content_frame" android:layout_width="match_parent" android:layout_height="match_parent" /> <ListView android:id="@+id/left_drawer" android:layout_width="240dp" android:layout_height="match_parent" android:layout_gravity="start" android:choiceMode="singleChoice" android:divider="@android:color/transparent" android:dividerHeight="0dp" android:background="#d0111111"/> </android.support.v4.widget.DrawerLayout>
I made the
FrameLayout tag bold in that file; that’s where all of my fragments are placed when I run the code I showed above.
When is a Fragment destroyed?
This code just made me wonder, “When is this fragment destroyed?” To test this I added an onDestroy() method to my fragment and logged a message when it was destroyed. onDestroy is actually called as soon as I switch to another fragment via my Navigation Drawer interface. That’s good to know.
Here’s a link to the official Android Fragments documentation page. Here’s another link to a useful article that discusses the fragment lifecycle, and shares some source code via Github to demonstrate it all.