Category Archives: Android

Flutter Databases Compared

What is the best Flutter Database?

Flutter Database options are still limited. We compare the available alternatives, and share performance benchmarks. 

How to persist data in Flutter / Dart?

The database market is a long-established saturated market and still experiencing double-digit growth. Most of that growth stems from NoSQL databases and newer database technologies, like time-series databases or graph databases. As Computing is shifting towards Decentralized Computing on the Edge, local databases that support decentralized data flows on Mobile, IoT, and other Embedded Devices come into focus. Some come from the Flutter data persistence world, and we will take a look at them in a second.

databases-time-history

Before we dive into the Flutter database options and compare them, we’re quickly carifying the term to make sure we share a common ground. Don’t worry, we’ll not get theoretical, but simply make sure we share a common language.

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IOT Android Things

Android Things for IoT developers

Android Things™ was revealed by Google on December 13, 2016. Formerly know as Brillo, which was announced during Google IO 2015, Android Things now is available as a developer preview. The Android Things SDK documentation basically says that developers can use almost the full Android stack for mobile. On top of that there is the “Things Support Library” offering APIs to interact with peripherals and “user drivers”. Both expose a Java API, so “user drivers” are not that close to the metal as the name might suggest.
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ORM FAQ

SQLite access with an ORM – FAQ

What is an Object-Relational-Mapper (ORM)?

An ORM is a layer between the relational SQLite database and the object-oriented app code. The ORM allows the developer to use the database without the need to transform objects into a format suited for the relational database.

Do I need an ORM to work with SQLite?

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Android ORM Performance 2016

With greenDAO 3 released, it’s time again to look at the Android ORM performance landscape and do some benchmarks. This time, we also tested newer ORMs for SQLite like DbFlow, requery, SQLDelight, and SquiDB. Also, we had an extensive look at benchmarks done by others. Let’s get started with our results:

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benchmarking on Android

Benchmarking on Android

I don’t believe in any statistics I didn’t fake myself (German saying)

Doing good performance benchmarks is hard and benchmarking on Android is no exception. Here is a checklist on how to do fair and robust benchmarks:

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keep your data safe with SQLCipher

Database Encryption for Android N: SQLCipher 3.5

SQLCipher 3.5.0 with support for Android N was released yesterday. Previous versions of SQLCipher linked to non-public Android libraries, a practice Google warned about earlier. Android N is getting stricter about linking to platform libraries. To comply with Android N, the SQLCipher authors did the necessary changes and also did a major code clean up. This results in a massive code reduction, as you can see in the following table:
SQLCipher 3.4
SQLCipher 3.5
AAR size
7.15 MB
2.87 MB
armeabi-v7a .so size
2.50 MB
1.43 MB
ICU size compressed / uncompressed
2.19 MB / 6.73 MB
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That's really good news. Just by using the new version 3.5.0 of SQLCipher, you can reduce your APK size (and build/deployment time). Not just the binary .so files got smaller, also the big "icudt46l.dat" file was removed in 3.5.0.

To see the effect in an app, we took the greenDAO example app and compared the resulting sizes. Of course, the version using built-in SQLite is by far the smallest, but your APK may lose 4.4 MB if you were using a previous version of SQLCipher:

SQLite
SQLCipher 3.4
SQLCipher 3.5
greenDAO Example APK size
70 KB
7.22 MB
2.80 MB
greenDAO Example size on device (Nexus 5x)
0,88 MB
17,89 MB
12.39 MB

We noticed one incompatibility with SQLCipher 3.5.x however. Android's SQLiteDatabase defines two additional collations:

In addition to SQLite's default BINARY collator, Android supplies two more, LOCALIZED, which changes with the system's current locale, and UNICODE, which is the Unicode Collation Algorithm and not tailored to the current locale.

Running SQL ORDER commands with "COLLATE LOCALIZED" does not work anymore starting with SQLCipher 3.5.0. That is the downside of the ICU (and ASOP code) removal.

So, what about greenDAO support for SQLCipher 3.5.x? greenDAO used "COLLATE LOCALIZED" in the QueryBuilder when specifying orders using string properties. To ensure compatibility with SQLCipher 3.5, we just released greendao-encryption V2.2.2 without the LOCALIZED collation.

Android Architecture with EventBus

Google’s Android Dev Summit 2015 covered a talk on Android Application Architecture. Android Apps often have complex interactions among data models, application logic, UI views and controllers, and networking. A solid architecture is the key to get this right. Watch the two Googlers Yigit Boyar and Adam Powell using EventBus as an important app’s component:

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