Nexus series, Google’s own son
miui
Meizu flyme
HTC Sense
huawei
native
Fragmentation problem
Screen size: 2.6 inches 3.2, 3.0, 3.5, 3.7, 4.0, 4.3, 4.7, 5, 5.1
Screen breakdown: 320*480, 480*800, 720P, 1080K, 2K, 4K
Study: Mobile adaptation
The Android developers web site: developer.android.com/index.html
SDK: SoftwareDevelopment Kit
JDK:Java Developer’s Kit
ADT: AndroidDevelopment Tools
1.1 introduction of Android
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The differences between Dalvik VM and JVM: 1. The differences between the bytecodes executed by Dalvik VM and JVM (bytecodes executed by Dalvik IN dex format and bytecodes executed by JVM in class format)
2. Different architectures based (Dalvik register-based, JVM stack-based: Register-based virtual machines take less time for larger programs to compile.)
New Virtual machine ART for Android
Dalvik: Every time an application is run, bytecode needs to be converted to machine code by the just-in-time compiler, which slows down the efficiency of the application
ART: When an application is first installed, bytecode is precompiled into machine code, making it a truly native application that can be launched and executed much faster
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1.2 Setting up the development environment
1. JDK: JavaDevelopment Kit
AS requires JDK7 or above
Eclipse requires JDK6 or above
2, the IDE
There are two options: AS, Eclipse
If you choose Eclipse, you will need to install the ADT plug-in
ADT: AndroidDevelopment Tools, is a plug-in on Eclipse, through the installation of plug-ins can be implemented in Eclipse Android development
Steps to install ADT in Eclipse:
Help – > Install New Software…
PS: It is recommended to use adT-bundle provided by Android
3, SDK: SoftwareDevelopment Kit
Main contents in the folder:
Docs: indicates an offline document
Platforms: Development platform
Case of samples:
Sources: source code for the API
System-images: system images for the virtual machine (AVD) that comes with the SDK
Sdkmanager. exe: SDK manager tool
Recommended website: www.androiddevtools.cn
PS: If your computer is Intel chip, then you can install Intel hardware acceleration driver, such as the installation of this manager error, so long need to restart the computer, enter the BIOS Settings. Go to the BIOS, find the IntelVirtual Technology option, and set it to Enabled.
Bind the SDK in Eclipse: Window — >Preferences — > Android — > SDK Location
4. Run and debug
1) Real machine debugging (recommended)
You need to install the driver for the machine on your system (you can do this using your phone assistant), and you need a USB cable
2) Virtual machine with SDK
3) Use a third-party VM: Genymotion
Note: 1. Registration is required before use
2. The version of Vitual Box should not be too new. 4.3.12 is recommended
3. If problems occur during use, you can run in compatibility mode. Note that if Genymotion is running in compatibility mode, then Eclipse (we will install the Genymotion plug-in in Eclipse) and VitualBox must also run in the same compatibility mode
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“Genymotion” : “http://plugins.genymotion.com/eclipse”
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The DDMS can be used to manage and monitor connected devices. However, the devices may be disconnected or disconnected
1. If you use a built-in VM, the VM of a later version will be disconnected from the phone function
2. The device connection times out. In this case, we just need to adjust the timeout time to a longer one
Window — > Preferences — > Android — > DDMS — > ADB Connection Timeout (ms)
What if the device has been disconnected?
1. Restart the VM
2. Restart ADB
3. Restart the computer
1.3 The first Android app
The Android system identifies applications by package name
Activity: We can think of it as a class that describes an interface in an APP
Project Catalog Introduction:
1, SRC: source code
Bin: a compiled file
3. Libs: third-party JAR package
4, gen: automatically generated file, do not need to modify
5. Android5.0.1: Android core API (including JavaSE core API)
AndroidPrivate Libraries: third-party JAR packages associated with the current project
7. Assets: Asset directory
8, res: resources folder, where resources files are stored
9. AndroidManifest: Manifest file (Important)
The contents of the manifest file mainly store the relevant information of the current project, such as package name, version, supported minimum system version, application name, title, theme and so on
Proguard-project. TXT: code obfuscation file
Properties: configuration file used to configure the compiled version of the current project