I used to have a Google Group for my subscribers, but I discontinued it several
years ago, steering people towards sites like Stack Overflow. But those sites
do not necessarily handle all sorts of questions — Stack Overflow in particular
has fairly stringent guidelines as to what is and is not on-topic.
So, I have set up a new discussion group, this time in the form of
a category on the CommonsWare Community site.
While the category is publicly readable, posting is limited to authorized
subscribers. The idea is that this category can be used for:
-
Questions about the books
-
Questions that might run afoul of Stack Overflow guidelines, such as asking
for suggestions for third-party libraries
-
Questions that you might have asked elsewhere and did not get the answers that
you sought
Subscribers can request permission to post by logging into
the Warescription site and visiting
Other Stuff > Settings from the nav bar. In there you will find a panel
for “Discussion Group Access” with details.
If you run into any problems in signing up for this,
let me know.
—Jul 25, 2017
Subscribers now have
access to Version 0.2 of GraphQL and Android, in PDF, EPUB, and
MOBI/Kindle formats. Just log into
your Warescription page and download
away, or set up an account and subscribe!
In this update, there are three new chapters:
-
One on authentication and the “viewer” pattern for having a schema based
on what the user is authorized to do
-
One on securing GraphQL access in Android, focusing at the moment on network
security
-
One on testing your GraphQL code, with a particular emphasis on different mocking
approaches
In addition:
-
All URLs in the samples and prose now point to 0.2/ instead of 0.1/
in their paths
-
The samples using Apollo-Android now use 0.3.3 of that library
-
There are a few errata fixes and the like.
The next update to this book should be out in 1-2 months.
—Jul 24, 2017
As part of my work on Android’s Architecture Components,
I put together CWAC-SafeRoom.
This is bridge code, connecting Room with SQLCipher for Android.
A little-known bit of the Architecture Components
is the SupportSQLite... series of interfaces. These
represent a wrapper around a SQLite implementation, with an API that is reminiscent
of the native SQLiteDatabase and related classes. Room not only has these
interfaces but an implementation (Framework...) that delegates to the native
Android classes. But, you can provide a SupportSQLiteOpenHelper.Factory
to your RoomDatabase.Builder, via openHelperFactory(), and that will
cause Room to use some other implementation of the SupportSQLite... bits.
That’s where CWAC-SafeRoom comes in.
So, if you have an EditText named passphraseField, you can initialize
an encrypted RoomDatabase via:
SafeHelperFactory factory=SafeHelperFactory.fromUser(passphraseField.getText());
StuffDatabase db=Room.databaseBuilder(ctxt, StuffDatabase.class, DB_NAME)
.openHelperFactory(factory)
.build();
Alternatively, you can create a SafeHelperFactory using a constructor that
takes a char[] parameter. As part of setting up the database, CWAC-SafeRoom
will clear that Editable (from getText() on your EditText) or that char[],
so that the passphrase is no longer in cleartext in memory.
CWAC-SafeRoom has been lightly tested — there is a reason for the 0.0.1
version. A fair bit of the SupportSQLite... API cannot be implemented using
SQLCipher for Android right now, as the SQLCipher for Android API is based on
very old versions of Android, and SupportSQLite... wants a few newer features.
So far, Room does not seem to be using those, which is why the partial
implementation of SupportSQLite... in CWAC-SafeRoom is holding up as well
as it is. Plus, Room itself is still an alpha, and who knows what the future
may bring?
(hopefully not zombies)
This library was developed with patent-pending Insta-Deprecation Technology™.
Should Google or Zetitec (developers of SQLCipher) offer their own equivalent
library, use theirs.
So, while work remains to be done, CWAC-SafeRoom demonstrates the possibility
of an encrypted Room implementation.
—Jul 11, 2017
Subscribers now have
access to the inaugural release of Android’s Architecture Components,
known as Version 0.1, in PDF, EPUB, and MOBI/Kindle formats. Just log into
your Warescription page and download
away, or set up an account and subscribe!
As I mentioned two weeks ago, when I released Version 0.1 of
GraphQL and Android,
I plan to break topics out into their own book when they are “bigger
than a breadbox”.
Google released the Architecture Components
to much fanfare at Google I|O 2017. This book will explore these components
in depth, identifying their pros and cons, along with how to apply them to your
Android projects. Particular emphasis will be placed on
Room,
given its comparative complexity.
This first beta version of the book covers the basics of using the Architecture
Components.
This book will evolve fairly rapidly over the next few months, to cover
topics like integration with RxJava and data binding, polymorphic Room relations,
and packaging databases with your app.
Stay tuned to this blog,
the @CommonsWare Twitter feed, etc. for
announcements about updates.
Again, if you have any questions or concerns,
drop me a line.
—Jul 10, 2017
As noted by Android Police,
Google has released a Samba client app for Android on the Play Store.
Users can use this app to connect their device to a SMB/CIFS file server, which
is the protocol typically used for Windows file servers.
And, as you can see from the source code,
the implementation is a DocumentsProvider. Any app that uses ACTION_OPEN_DOCUMENT,
ACTION_OPEN_DOCUMENT_TREE, or ACTION_CREATE_DOCUMENT can now work seamlessly
with Windows file servers… except for those apps written by developers who keep
insisting that a Uri always points to a local file.
If you are using these Storage Access Framework actions, the Uri that you
get back does not have to point to anything on the device’s filesystem that
you can access. Always use a ContentResolver and openInputStream()/openOutputStream()
to manipulate the content. For more, see
this post from March 2016.
—Jul 06, 2017
