TAILIEUCHUNG - Lập trình Androi part 41

Trong cuối những năm 1990, một làn sóng virus lây lan qua mạng Internet, gửi qua e-mail, sử dụng thông tin liên lạc từ Microsoft Outlook tiêu huỷ. Một virus sẽ đơn giản chỉ e-mail các bản sao của chính nó tới từng địa chỉ liên lạc Outlook rằng đã có một địa chỉ e-mail. Điều này là có thể bởi vì, vào thời điểm đó, Outlook đã không mất bất kỳ bước nào để bảo vệ dữ liệu từ các chương trình bằng cách sử dụng API Outlook, vì đó API được thiết kế cho các nhà phát triển. | Chapter Requesting and Requiring Permissions In the late 1990s a wave of viruses spread through the Internet delivered via e-mail using contact information culled from Microsoft Outlook. A virus would simply e-mail copies of itself to each of the Outlook contacts that had an e-mail address. This was possible because at the time Outlook did not take any steps to protect data from programs using the Outlook API since that API was designed for ordinary developers not virus authors. Nowadays many applications that hold onto contact data secure that data by requiring that a user explicitly grant rights for other programs to access the contact information. Those rights could be granted on a case-by-case basis or a once at install time. Android is no different in that it requires permissions for applications to read or write contact data. Android s permission system is useful well beyond contact data and for content providers and services other than those supplied by the Android framework. You as an Android developer will frequently need to ensure your applications have the appropriate permissions to do what you want to do with other applications data. You may also elect to require permissions for other applications to use your data or services if you make those available to other Android components. This chapter covers how to accomplish both these ends. Mother May I Requesting the use of other applications data or services requires the uses-permission element to be added to your file. Your manifest may have zero or more uses-permission elements all as direct children of the root manifest element. 275 CHAPTER 28 Requesting and Requiring Permissions The uses-permission element takes a single attribute android name which is the name of the permission your application requires uses-permission android name All of the stock system permissions begin with and are listed in the Android SDK documentation for

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