Architecture diagram for Android

1.Applications

This layer is the Android application layer.

Each application must be developed using the Android system-designed application framework (application framework).

The current development environment is Eclipse + ADT, where detailed installation can be found online. The development language is Java, and code written in other languages (such as C, C + +) can be called by JNI, which requires the NDK to be installed. When the Android system is published, it usually presets some apps that are often used, such as phone. Contacts Phone, Maps,browser,email, gallery and so on. The SDK comes with the samples Apidemos almost contains all the use of the API, is a good learning material.

2. Application Framework

provides an application development framework and its management model. Contains

1) Activity manager:activity Manager maintains the lifecycle of the application and provides a consistent navigation mechanism.

2) Window Manager: Manage window-related methods and properties.

3) Content Provider: Provides an inter-application data sharing mechanism through a common interface. The ability to allow a program to share its own data with other programs.

4) View System: Standard control. Contains DatePicker, Timepicker, Spinner, AutoComplete, Button, EditText, CheckBox, Radio, ImageButton, Gallery, Imageswitcher, ListView, GridView and LinearLayout, relativelayout, tablelayout three kinds of layout management algorithms, very useful.

5) Notification Manager: Define your own cue flag management, these flags will be displayed in the phone status bar.

6) Package Manager: Provides management functions related to the package

7) Telephony Manager: Provides mobile device function interface. For example, battery, network, etc.

8) Resource Manager: provides the ability to access non-code resources. Resources such as localized strings, pictures, layouts, etc.

9) location Manager: provides a GPS or network-based position access interface

3.Libraries

1) Surface Manager: Layers that combine multiple apps are displayed on a physical device

2) Opengl|es:3d Graphics library

3) sgl:2d Graphics library

4) Media Framework: PacketVideo-based Opencore, supports playback and recording of many popular audio video formats as well as static image formats. Contains MPEG4, H. MP3, AAC, AMR, JPG, PNG.

5) FreeType: Bitmap font and vector font rendering

6) SSL: Secure Communication

7) SQLite: A Lightweight relational database

8) Webkit:web engine

9) LIBC: System C Library

4.Android Runtime

1) Core Libraries:java Kernel class library

2) Dalvik virtual machine: Dalvik is Google's own Java VM designed for Android, which is based on a register rather than a stack of virtual machines. A file that runs the. Dex (that is, Dalvik executable) format, which is a compression format designed for Dalvik, reduces overall file size, improves I/O operations, class lookup speed, and is therefore more suitable for resource-constrained systems such as mobile phones.. dex files are used with DX The tool is converted from a Java. class file. All files for Android apps (including *.so) will eventually be packaged as. apk files that can be executed on simulatore/phones after installation.

5.Linux Kernel

The Linux kernel provides the core functions of the operating system, including various hardware drivers, power Management.

Architecture diagram for Android