Android Java 框架基础[知识点汇总]-阿里云开发者社区

开发者社区> 狗尾巴呢> 正文

Android Java 框架基础[知识点汇总]

简介: 学习android的过程中,把整个框架的基础结构牢记很重要,特此摘录了一些这个框架的一些基础知识,在使用的过程中按照这个框架学习,事半功倍。 开发过程中参考JDK的文档和android的sdk文档可以清楚遇到的很多问题,遇到问题是现在这两个文档中一般都能找到原因(安装sdk的文档参考http://www.
+关注继续查看

学习android的过程中,把整个框架的基础结构牢记很重要,特此摘录了一些这个框架的一些基础知识,在使用的过程中按照这个框架学习,事半功倍。

开发过程中参考JDK的文档和android的sdk文档可以清楚遇到的很多问题,遇到问题是现在这两个文档中一般都能找到原因(安装sdk的文档参考http://www.cnblogs.com/2018/archive/2011/02/17/1957356.html

分层结构Android Layers

Ø Prominent code libraries, including:

– Browser technology from WebKit, the same open source engine powering Mac’s Safari and the iPhone’s Mobile Safari browser. WebKit has become the de facto standard for most mobile platforms.

– Database support via SQLite, an easy-to-use SQL database.

– Advanced graphics support, including 2D, 3D, animation from Scalable Games Language (SGL), and OpenGL ES.

– Audio and video media support from PacketVideo’sOpenCORE, and Google’s own Stagefright media framework.

– Secure Sockets Layer (SSL) capabilities from the Apache project.

Ø An array of managers that provide service

– Activities and views – Telephony

– Windows – Resources

– Location-based services

Ø The Android runtime, which provides:

– Core Java packages for a nearly full-featured Java programming environment. Note that this isn’t a Java ME environment.

– The Dalvik VM employs services of the Linux-based kernel to provide an environment to host Android applications.

Ø A Linux kernel

provides a foundational hardware abstraction layer, as well as core services such as process, memory, and filesystem management. The kernel is where hardware-specific drivers are implemented—capabilities such as Wi-Fi and Bluetooth are here. The Android stack is designed to be flexible, with many optional components that largely rely on the availability of specific hardware on a given device. These components include features such as touch screens, cameras, GPS receivers, and accelerometers.

API Level

API Level is an integer value that uniquely identifies the framework API revision offered by a version of the Android platform.

Platform Version

API Level

Android 2.3

9

Android 2.2

8

Android 2.1

7

Android 2.0.1

6

Android 2.0

5

Android 1.6

4

Android 1.5

3

Android 1.1

2

Android 1.0

1

Intent IntentFilters

Intents and IntentFilters, Android’s innovative navigation and triggering mechanisms.

 An Intent is a declaration of need. It’s made up of a number of pieces of information that describe the desired action or service. We’re going to examine the requested action and, generically, the data that accompanies the requested action.

 An IntentFilter is a declaration of capability and interest in offering assistance to those in need. It can be generic or specific with respect to which Intents it offers to service.

The action attribute of an Intent is typically a verb,The data component of an Intent is expressed in the form of a URI

The IntentFilter defines the relationship between the Intent and the application. IntentFilters can be specific to the data portion of the Intent, the action portion, or both. IntentFilters also contain a field known as a category. The category helps classify the action.

IntentFilters are often defined in an application’s AndroidManifest.xml file with the <intent-filter> tag.

Activity

An application might have a UI, but it doesn’t have to have one. If it has a UI, it’ll have at least one Activity.

Service

If an application is to have a long lifecycle, it’s often best to put it into a Service.

BroadcastReceiver

If an application wants to receive and respond to a global event, such as a ringing phone or an incoming text message, it must register as a BroadcastReceiver.

ContentProvider

If an application manages data and needs to expose that data to other applications running in the Android environment, you should consider a ContentProvider.

AndroidManifest.xml

A fundamental fact of Android development is that an Android application contains at least one Activity, Service, BroadcastReceiver, or ContentProvider. Some of these elements advertise the Intents they’re interested in processing via the IntentFilter mechanism. All these pieces of information need to be tied together for an Android application to execute. The glue mechanism for this task of defining relationships is the AndroidManifest.xml file.

<service>Servicemight also include the <intent-filter>

<receiver>BroadcastReceivermight have an explicit <intent-filter> tag

<uses-permission>

<application

Core Android packages

 java.lang—Core Java language classes

 java.io—Input/output capabilities

 java.net—Network connections

 java.text—Text-handling utilities

 java.math—Math and number-manipulation classes

 javax.net—Network classes

 javax.security—Security-related classes

 javax.xml—DOM-based XML classes

 org.apache.*—HTTP-related classes

 org.xml—SAX-based XML classes

android.app—Android application model access

android.bluetooth—Android’s Bluetooth functionality

android.content—Accessing and publishing data in Android

android.net—Contains the Uri class, used for accessing content

android.gesture—Create, recognize, load, and save gestures

android.graphics—Graphics primitives

android.location—Location-based services (such as GPS)

android.opengl—OpenGL classes

android.os—System-level access to the Android environment

android.provider—ContentProvider-related classes

android.telephony—Telephony capability access, including support for both Code Division Multiple Access (CDMA) and Global System for Mobile communication (GSM) devices

android.text—Text layout

android.util—Collection of utilities for logging and text manipulation, including XML

android.view—UI elements

android.webkit—Browser functionality

android.widget—More UI elements

Application Fundamentals

SDK的文档目录file:///。。。/android-sdk-windows/docs/guide/topics/fundamentals.html 有详细的说明

Activity lifecycle

As an activity transitions from state to state, it is notified of the change by calls to the following protected methods:

voidonCreate(Bundle savedInstanceState)
void onStart()
void onRestart()
void onResume()
void onPause()
void onStop()
void onDestroy()

由Android SDK/NDK默认管理的目录和文件:

AndroidManifest.xml

软件的android关键配置文件

涉及安全、启动的Activty等

default.properties

API Level的设置等

proguard.cfg

代码混淆使用

界面资源和访问代码

res gen 两个字目录下的文件

res下有如下类别

 res/anim:用XML表示的基于帧的动画

 res/drawable:不同规格的图标、图片等,drawable-hdpidrawable-ldpidrawable-mdpi三个子目录

 res/layout:视图对象的XML表示

 res/values:strings, colors, styles, dimensions, arrays的XML表示

 res/xml:User-defined XML files that are compiled into a binary representation

 res/raw:Arbitrary and uncompiled files that can be added

gen res中加入的资源在gen中生成访问代码R.java

assets

数据等文件

android.content.res.AssetManager asset = Application.getAssets()这个类辅助访问

src

JAVA代码

NDK

Jniobj libs目录

Jni: 放C/C++代码

Obj/libs:是c/c++的编译obj文件和so库

在这些默认文件和目录的基础上可以加入自己的需要管理的目录或文件

版权声明:本文内容由阿里云实名注册用户自发贡献,版权归原作者所有,阿里云开发者社区不拥有其著作权,亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容,填写侵权投诉表单进行举报,一经查实,本社区将立刻删除涉嫌侵权内容。

相关文章
Android Java 框架基础[知识点汇总]
学习android的过程中,把整个框架的基础结构牢记很重要,特此摘录了一些这个框架的一些基础知识,在使用的过程中按照这个框架学习,事半功倍。 开发过程中参考JDK的文档和android的sdk文档可以清楚遇到的很多问题,遇到问题是现在这两个文档中一般都能找到原因(安装sdk的文档参考http://www.
807 0
Android JAVA 语言基础例子代码
Android的界面一般都是java开发的,因此对于c++,.net人员来说理解和编写有一个适应过程,最近参考了一下资料,把这些涉的一些java基础使用以例子代码的形式总结起来,记录了这个平台的熟悉过程。
857 0
Java面试通关要点汇总集
框架篇SpringBeanFactory 和 ApplicationContext 有什么区别Spring Bean 的生命周期Spring IOC 如何实现说说 Spring AOPSpring AOP 实现原理动态代理...
1291 0
Java编程笔记,spring boot常用属性汇总
  这些属性是否生效取决于对应的组件是否声明为 Spring 应用程序上下文里的 Bean(基本是自动配置的),为一个不生效的组件设置属性是没有用的。
1334 0
Spring 框架基础(03):核心思想 IOC 说明,案例演示
本文源码:GitHub·点这里 || GitEE·点这里 一、IOC控制反转 1、IOC容器思想 Java系统中对象耦合关系十分复杂,系统的各模块之间依赖,微服务模块之间的相互调用请求,都是这个道理。
2000 0
搜狗地图2016-Android-社招笔试题(包含Java基础部分)
下面是搜狗地图的社招笔试题,由于条件有限,全是手机拍的,请将就着看。另请忽略上面的答案,不一定准确。 大伙可在下方讨论答案,上方答案仅供参考,不一定准确。 $(function () { $('pre.
1022 0
+关注
狗尾巴呢
从事研发20年 涉及桌面软件、嵌入式设备、C/S分层系统、B/S业务系统、互联网系统等等各类系统 语言涉及C/C++ .net系统 java系列 前端系列等等不同的类别 主控和主导了国家863项目,企业业务应用系统,自然语言翻译系统,数据库审计等系列的软件研发
435
文章
2
问答
文章排行榜
最热
最新
相关电子书
更多
《2021云上架构与运维峰会演讲合集》
立即下载
《零基础CSS入门教程》
立即下载
《零基础HTML入门教程》
立即下载