Android learning process (1) Introduction to mobile platform development

Start the Android development journey from this section.

(1) Mobile development:

Mobile development is also known as Mobile Internet development . is based on PDA (Personal Digital assitant Personal digital assistant), UMPC (Ultra-mobil Personal Computer Super Mobile PC) and other portable terminals as the basis for the corresponding development work. Because these mobile devices are wireless internet access, the industry is also known as Wireless development .

Industrial-grade PDA has a barcode scanner, RFID (Radio Frequency identification Radio frequency identification) reader, POS (point of Sale Sales terminal) machine.

Consumer electronics PDAs include smartphones, tablets, handheld games consoles, wearable devices and more.

(2) Android history:

1) 2005

Google acquires Android.inc

Start Dalvik

2) 2007

Open Mobile Alliance established

sdk1.0 Preview Release

3) 2008

Google's first mobile developer contest

Google T-mobile G1 released

SDK (software Development Kit) 1.0 released

Android Open source code (Apache License)

Expand your knowledge :

Android version: Major version number. minor version number. Dressing number (usually the number of fixed bugs)

(3) 3G third generation Digital communication technology (3rd Generation):

The main difference between 3G and 2G is the increase in the speed of transmitting sound and data

1) In 1995, the first generation of analog mobile phones can only make voice calls;

2) 1996 to 1997, the second generation of GSM and CDMA digital Phone (2G) increased the ability to receive data;

3) 3g is the third generation of communication network, currently supports the three wireless interface standards established by ITU

1 CDMA2000 of China Telecom (used in Japan, Korea and North America) 2 China Unicom's WCDMA (most of the world's 3G networks are using this standard) 3. China Mobile's TD-SCDMA (PRC)

Evolution of communication technologies :

GSM (9k)->gprs (42k)->edge (172k)->WCDMA (364k)->HSDPA (7.2M)->FDD (300M)->lte long-term evolution

　　

(4) Android System Architecture:

1) The Android platform is a software stack for mobile devices, including:

Complete mobile OS middleware key applications

2) The bottom layer is Linux

Security Management memory management process management power management hardware Drivers

(5) Dalvik virtual machines vs. JVM virtual machines:

1) Why Google is developing Dalvik virtual machines

Copyright Issues further optimization of virtual machine performance

2) Difference: (. dex file is a consolidation of all class files)

Virtual Machines              The JVM                  Dalvik the compilation process           . java->.  Class         . Java->.  the schemas supported by class-I are          based on a stack                  -based register

A Dalvik virtual machine creates an instance of itself for each Android app.

Android learning process (1) Introduction to mobile platform development