Android Study Notes-Basics

Android system framework (including the Linux operating system, middleware, C Class Library and core applications) 1. You can customize the XML file in res -- values under the project: Enter color, array, styles2 can use the getresources () function 3 package is the main package name of the entire Java application, and it is a default framework name 3. In this file, Android: icon indicates the application's LogoAndroid: label indicates the intent-filter intent filter of the application, which is used to filter users' action actions. Action Android: Name = "android. intent. action. main "indicates that the current program is the project's entry program category Android: Name =" android. intent. category. launcher "indicates whether to display the android lifecycle 1 activity lifecycle: Overall lifecycle: oncreate->... -> ondestroy visual life cycle: onstart-> .... -> onstop focus life cycle: onresume-> onpause 2 Android is released along with core applications, including the e-mail client, SMS Short Message program, calendar, MAP, browser, 3 Application Frameworks: 1. views, list (lists), Grid, text box, button, or embedded web browser 2. the Content Manager (content providers) enables the application Chen Xu to access data of another application. resource Manager (resourse manager) provides access to non-code resources. notification Manager allows applications to display customer notification information in the status bar. activity manager is used to manage application lifecycles and provides common navigation rollback functions. 4. Library: system C library, the library of standard function libraries inherited from BSD, surface Manager (display subsystem management), libwebcore (Web browser engine), SGL (2d graphics engine), 3D libraries (OpenGL ES 1.0 APIs), FreeType (bitmap and vector) SQLite (powerful lightweight relational database engine) 5 Runtime Library: Dalvik virtual The host depends on some Linux functions, such as the thread mechanism and the underlying memory management mechanism. 6. the Linux kernel depends on the 2.6 kernel, such as security, memory management, and process management, network Protocol and Driver Model 7 Android Application Components: Android applications do not have an agreed entry. Each application is independent of each other and runs in its own process. Android has four core components: acticity, service, and broadcase javaser contentprovider. The navigation between the same component and different components is completed through intent. In addition, a view class is defined to display visual interfaces, such as menus, dialogs, and down lists. Other components are described as follows: activity. Each activity is implemented as an independent class, you can call startactivity to navigate from one screen to another. The conditions for opening the activity are encapsulated in intent. When a new screen is opened, the previous screen is paused and saved in the history stack. You can return the previous screen in the stack. When the screen is no longer used, you can also delete it from the history stack. By default, Android retains the running screen service from the screen to every application. It is a long-lived program without a user interface. Content. startservice () starts a service, content. bindservice () method to connect to a service broadcast receiver Er: A component contentprovider provided to implement system broadcast: to share data between different components intent: it is the bond between different components and encapsulates the conditions for finding navigation of different components (data corresponding to actions and actions, and data is expressed as URIs ). For example, to view the contact form of a person, you need to create an intent with the action type as view and a URI that represents the person.