Basic tutorial for Android-1.1 Background and System Architecture Analysis

Basic tutorial for Android-1.1 Background and System Architecture Analysis
Basic tutorial for Android-1.1 Background and System Architecture Analysis

1. Android background and current situation

Android was created by Andy Rubin and later acquired by Google. The earliest version was Android 1.1.
The latest version is Android M released at Google I/O conference 5.28 this year. Interestingly, the names of Android systems are all named after snacks, the following table lists the names of 15 Android versions, corresponding to the API number and release time!

System Version name	API version	Release Date
Android 1.5: Cupcake: paper cup cake	3	2009.4.30
Android 1.6: Donut	4	2009.9.15
Android 2.0/2.0.1/2.1: Eclair: muffins	5/6/7	2009.10.26
Android 2.2/2.2.1: Froyo: Frozen yogurt	8	2010.5.20
Android 2.3: Gingerbread: ginger pie	9	2010.12.7
Android 3.0: Honeycomb	11	2011.2.2
Android 3.1: Honeycomb	12	2011.5.11
Android 3.2: Honeycomb	13	2011.7.13
Android 4.0: Ice Cream Sandwich	14	2011.10.19
Android 4.1: Jelly Bean	16	2.6.2.6.28
Android 4.2: Jelly Bean	17	2012.10.30
Android 4.3: Jelly Bean	18	2013.7.25
Android 4.4: KitKat: Chocolate	19	2013.11.01
Android 5.0: Donut: lollipop	21	2014.10.16
Android M: preview	22	2015.5.28

Well, in addition to the public versions above, there are also some other versions. As of 2015.1, the market share of each version is as follows:

After reading the above information, we may have such a question:
Which version should we develop when developing so many system versions?
This is the "Fragmentation" problem that Android must face. There are two problems:
① System fragmentation: we may need to be compatible with earlier versions when developing apps. For example, the minimum version is 2.3. Due to the prevalence of various Rom customization, Chinese people like to make some changes to the native system, this leads to the native system, but the custom Rom is not feasible, such as the camera call ~
② Screen fragmentation: mobile phones of various screen sizes on the market, 4.3, 4.5, 4.7, 5.0, 5.3... And so on, apart from cell phones and Android tablets, we may have to deal with this screen adaptation problem during development. Of course, we don't need to consider these complicated things as we just learned, let's explore the actual development in the future!

2. Android system features and platform architecture system features:

• Application Framework SupportComponent Reuse and replacement(The app follows the framework conventions when it is released. Other apps can also use this module)
• DalvikVirtual Machine: optimized for mobile devices
  -Integrated browser: Open-SourceWebKitEngine
• SQLiteStructured Data Storage
• Optimized graphics library, multimedia support, GSM phone technology, Bluetooth, etc.
• UseSoftware StackMethod Construction

Platform diagram:

A simple understanding of the Architecture:

3. Summary in this section:

This section describes the historical background and status quo of Android, and briefly analyzes the system features and architecture of Android. We can understand these concepts, in the next section, we will start building the Android environment!

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