【正文】 Service FriendTracker control FriendViewer application Friend Receiver Broadcast receiver Activity FriendTracker Activity FriendViewer Figure 1. Example Android application. The FriendTracker and FriendViewer applications consist of multiple ponents of different types, each of which provides a different set of functionalities. Activities provide a user interface, services execute background processing, content providers are data storage facilities, and broadcast receivers act as mailboxes for messages from other applications. ions randomly, but extending the ponent to interface with a Web service is straightforward. The FriendProvider content provider maintains the most recent geographic coordinates for friends, the FriendTrackerControl activity defines a user interface for starting and stopping the tracking functionality, and the BootReceiver broadcast receiver obtains a notification from the system once it boots (the application uses this to automatically start the FriendTracker service).The FriendViewer application is primarily concerned with showing information about friends’ locations. The FriendViewer activity lists all friends and their geographic coordinates, and the FriendMap activity displays them on a map. The Friend Receiver broadcast receiver waits for messages that indicate the physical phone is near a particular friend and displays a message to the user upon such an event. Although we could have placed these ponents within the FriendTracker application, we created a separate application to demonstrate crossapplication munication. additionally, by separating the tracking and user interface logic, we can create alternative user interfaces with different displays and features—that is, many applications can reuse the logic performed in FriendTracker. Component Interaction The primary mechanism for ponent interaction is an intent, which is simply a message object containing a destination ponent address and data. The Android API defines methods that accept intents, and uses that information to start activities (startActivity(Intent)), start services (startService (Intent)), and broadcast messages (sendBroadcast(Intent)). The invocation of these methods tells the Android framework to begin executing code in the target application. This process of interponent munication is known as an action. Simply put, an intent object defines the “intent” to perform an “action.”O(jiān)ne of Android’s most powerful features is the flexibility allowed by its intentaddressing mechanism. Although developers can uniquely address a target ponent using its application’s namespace, they can also specify an implicit name. In the latter case, the system determines the best ponent for an action by considering the set of installed applications and user choices. The implicit name is called an action string because it specifies the type of requested action—for example, if the “VIEW” action string is specified in an intent with data fields pointing to an image file, the system will direct the intent to the preferred image viewer. Developers also use action strings to broadcast a message to a group of broadcast receivers. On the receiving end, developers use an intent filter to subscribe to specific action strings. Android includes additional destination resolution rules, but action strings with optional data types are the most mon. Figure 2 shows the interaction between ponents in the FriendTracker and FriendViewer applications and with ponents in applications defined as part of the base Android distribution. In each case, one ponent initiates munication with another. For simplicity, we call this interponent munication (ICC). In many ways, ICC is analogous to interposes munication (IPC) in Unixbased systems. To the developer, ICC functions identically regardless of whether the target is in the same or different application, with the exception of the security rules defined later in this article. The available ICC actions depend on the target ponent. Each ponent type supports interaction specific to its type for example, when FriendViewer starts FriendMap, the FriendMap activity appears on the screen. Service ponents support start, stop, and bind actions, so the FriendTrackerControl activity, for instance, can start and stop the FriendTracker service that runs in the background. The bind action establishes a connection between ponents, allowing the initiator to execute RPCs defined by the service. In our example, FriendTracker binds to the location manager in the system server.中文譯文深入理解Android系統(tǒng)安全性下一代開放操作系統(tǒng)的主流將不會在桌面上，但是將會出現(xiàn)在我們每天攜帶的手機上。這些開放性的環(huán)境將會帶領這些新的應用可能集成這些已經存在的在線服務，當然隨著日以具增的數(shù)據與服務在手機上的支持，手機上的安全缺陷也越發(fā)明顯。下一代操作系統(tǒng)本質在于是否提供一個完整綜合的安全平臺。由開放手機聯(lián)盟（open Handset Alliance 谷歌領導）所開發(fā)的android 系統(tǒng)是一個被廣泛看好的一個手機開源系統(tǒng)，該系統(tǒng)提供一個基本的操作系統(tǒng)，一個中間件應用層，一個java開發(fā)工具和一個系統(tǒng)應用收集器（collection of system applications ）。盡管android SDK自2007年就發(fā)布了，但是第一部android 手機卻在2008年10月才誕生。自從這時起谷歌開起了自己的時代，TMobile的G1的制造商臺灣 HTC估算G1的發(fā)貨量在2008年底已經超過100萬部。不久的將來其他許多手機供應商要計劃支持這個系統(tǒng)。一個圍繞android龐大的開發(fā)者社區(qū)已經建立，同時很多新的產品和應用已經可以在android上使用。一個Android的主要賣點是它使開發(fā)人員無縫把在線服務擴展到手機。這方面最明顯的例子是谷歌的緊密集成Gmail，日歷和聯(lián)系人Web應用程序通過該系統(tǒng)。用戶只需提供一個android用戶名和密碼，其手機自動同步與谷歌的服務。其他廠商正在迅速適應自己的現(xiàn)有的即時通訊，社交網絡和游戲服務。Android和許多企業(yè)尋找新途徑來整合他們的自己已有的業(yè)務到android上。 傳統(tǒng)的臺式機和服務器的操作系統(tǒng)一直在努力進行安全功能的集成。這些個人和商業(yè)應用在單一平臺的很出色，然而這一塊業(yè)務一個手機平臺上像android上不是很有用。它給了許多研究人員希望。Android沒有停在為其他平臺體用應用支持：應用的執(zhí)行依賴于頂層JAVA中間件，這個中間件運行在嵌入式Linux 內核之上。所以開發(fā)人員要把他們的應用部署到Android必須使用其自定義的用戶界面環(huán)境。此外，android系統(tǒng)應用限制各應用相互調用API協(xié)作，并且對方為自己的用戶應用進行身份驗證。盡管這些應用有一定的安全特性，我們一些有經驗的開發(fā)人員開發(fā)android應用人士透露，設計安全應用程序并不總是直線前進的。Android使用一個簡單的許可標簽分配模式限制訪問的資源，但其他應用程序的原因必要性和便利，其設計師們增加了困惑對這個系統(tǒng)。本文試圖對Android的安全的復雜性進行講解，并注意一些可能的發(fā)展缺陷以及應用程序的安全。我們通過嘗試得出一些經驗教訓，希望對未來的安全有用。Android Application Android應用程序框架對開發(fā)者來說是一個強制架構。它沒有一個main（）函數(shù)功能或單一入口點執(zhí)行，相反，開發(fā)人員必須在設計方面的應用組件。我們開發(fā)的應用對android的sdk的幫助的API。Example Application。我們開發(fā)了一個描述如何創(chuàng)建android的應用。有興趣的讀者可以去我們的站點下載讓我們考慮一個基于位置的社交網絡應用，其中手機用戶可以通過本應用發(fā)現(xiàn)他們的朋友們位置。我們進行功能拆分，分成兩個應用程序：一個用于跟蹤查看朋友和?？此麄儭? 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