第二章 操作Android Studio
Android Studio is a windowed environment. To make the best use of limited screen real-estate,and to keep you from being overwhelmed, Android Studio displays only a small fraction of the available windows at any given time. Some of these windows are context-sensitive and appear only when the context is appropriate, while others remain hidden until you decide to show them, or conversely remain visible until you decide to hide them. To take full advantage of Android Studio, you need to understand the functions of these windows, as well as how and when to display them. In this chapter, we’re going to show you how to manage the windows within Android Studio.
Android Studio是一款视窗化的集成开发环境。为了充分使用实际的屏幕的面积、防止你变得抓狂，在任何时候Android Studio只在窗口显示一部分功能。那些窗口都是上下文相关的，并且只有在当前需要的时候才会出现。其它的功能一般都是隐藏的，除非你故意将它们显示出来。相反，你也可以故意将一些功能隐藏，只显示其中一些功能。为了能充分的使用Android Studio，你需要理解这些窗口的意思，并且要清楚何时还有什么时候将这些窗口显示出来。在这一章，我们会带你学习如何管理Android Studio中的这些窗口
One of the essential functions of any integrated development environment (IDE) is navigation.Android projects are typically composed of many packages, directories, and files, and an Android project of even modest complexity can contain hundreds of such assets. Your productivity with Android Studio will depend in large measure on how comfortable you are navigating within these assets and across them. In this chapter, we’re also going to show you how to navigate in Android Studio.
集成开发环境至关重要的一个功能就是它的操作性。Android工程通常是由许多的包、目录和文件组成的，并且一个普通的Android工程都可能包含有成百的这些东西。你使用Android Studio的生产效率在很大程度上取决于你对这些东西操作的舒适程度。在这一章，我们也会教你如何操作Android Studio。
Finally, we’ll show you how to use the help system within Android Studio. To take full advantage of this chapter, open the HelloWorld project we created in Chapter 1. If this project is already open in Android Studio, you’re ready to go. Please refer to Figure 2-1 as we discuss the following navigation features.
最后，我们将会教你如何使用Android Studio内置的帮助系统。为了能学好这一章，打开我们在第一章中建立的工程——HelloWorld。如果这个工程已经在Android Studio中打开了，你就准备好开始学习这一章吧。请看图2-1的详细说明
The Editor
编辑器
The primary purpose of any IDE is to edit files. As one would expect, the window that allows users to edit files in Android Studio is located in the center pane of the IDE. The Editor window is unique among windows in that it is always visible and always located in the center pane.
一个IDE最重要的功能就是编辑文件。果然，在Android Studio中，用户编辑文件的区域就在IDE的中间。编辑器的窗口总是在IDE的中间而且总是可见的。
In fact, the Editor window is such a pervasive feature of Android Studio that from here on out, we refer to it simply as the Editor. All the other windows in Android Studio are called tool windows and cluster in side panes (left, bottom, and right) around the Editor.
事实上，从现在开始，编辑窗口就是Android Studio的一个很普通的特点，我们指的是它作为编辑器的简洁性。在Android Studio中所有的其它的窗口都被叫做工具窗口和工具集，它们都分布在编辑器的周围（左边，下边，右边）。
The Editor is a tabbed window, and in this respect it resembles a contemporary web browser. When you open a file from one of the tool windows, from a keyboard shortcut, or from a context menu, the file displays as a tab of the Editor. As you already discovered when you built your first project, HelloWorld, the MainActivity.java and the activity_main.xml files were automatically loaded in the Editor as tabs. Android Studio tries to anticipate which files you’re likely to start editing, and then opens them automatically as tabs in the Editor upon completion of the New Project Wizard. Virtually any file may be opened in the Editor, though raw image and sound files cannot (yet) be edited from within Android Studio. You may also drag and drop a file from a tool window onto the Editor; doing this opens the file as a tab in the Editor. Along the top of the Editor are the Editor tabs. Along the left margin of the Editor is the gutter, and along the right margin of the Editor is the marker bar. Let’s examine each in turn.
这个编辑器是一个分页式的窗口，在这一方面，它就像是现在的网页浏览器。当你从一个工具窗口、快捷键或者快捷菜单打开一个文件的时候，这个文件就会作为编辑器的一个分页显示出来。在你创建你的第一个工程HelloWorld的时候你已经发现了，MainActivety.java文件和activity_main.xml文件都会像网页一样自动加载到编辑器上。New Project Wizard一完成，Android Studio尝试着提前去确定你可能开始编辑的文件，然后自动在编辑器中打开它，就像打开一个网页一样。实际上，某些文件也可能会在这个编辑器中打开，尽管在Android Studio中，原始的图片和声音文件不能被编辑。你也可能从工具窗口向编辑器中拖入一个文件，在编辑器中打开一个文件就像是打开了一个网页。
�Editor Tabs
编辑器选项卡
To navigate among Editor tabs in Android Studio, use the Alt+Right-Arrow | Ctrl+Right-Arrow or Alt+Left-Arrow | Ctrl+Left-Arrow keys. Of course, you may always select an Editor tab with your mouse. The Editor tabs’ options are located in the main menu bar at Window ➤ Editor Tabs. Any action you select from this menu applies to the currently selected tab. Roll your mouse over the MainActivity.java tab and right-click (Ctrl-click on Mac) it. In the resulting context menu, shown in Figure 2-2, you will notice many of the same options that you discovered in Window ➤ Editor Tabs. From this context menu, select the Tabs Placement submenu. The menu options Top, Bottom, Left, and Right allow you to move the tabs bar.Moving the tabs bar to the right or left accommodates more visible tabs, though at the expense of screen real-estate.
为了操作Android Studio中的编辑器选项，使用Alt+方向键（四个方向键）。当然，你可以用鼠标选择一个编辑器选项。编辑器的选项表的选项在主菜单栏：Window->Editor Tabs。你在这个菜单选中的任何选中的页面。如图2-2，将鼠标放在MainActivity.java页面中，右击鼠标，你将会发现你看到的和Windows->Editor Tabs中是一样。从这个快捷菜单中选中Tabs Placement子菜单。菜单的选中有Top,Bottom,Left,Right(上下左右)四个选项允许你移动选项卡。根据你的桌面的实际使用面积来移动你的选项卡，向左或者向右移动，保证你能够看到更多的选项卡。
The Close and Close All actions of the Editor tab context menu are straightforward. The Close Others action is used when you want to close all the tabs except the active tab. The Split Vertically and Split Horizontally actions are used to subdivide your Editor into panes. Split Vertically is particularly useful if you want to compare two files side by side. You may split panes ad infinitum, though the utility of such nested splits quickly diminishes. You may also drag and drop files from other windows to any pane of the Editor, or from one pane to another. Closing the last tab of a pane causes the entire pane to disappear.
关闭和关闭编辑器所有选项的操作的快捷菜单是非常简单的。当你想要关闭除了现用标栏之外的其它所有标栏时，关闭其它标栏的功能就可以被使用。Split Vertically(垂直分离)和Split Horizontal)y(水平分离)两个操作可以对你的编辑器的面板进行再细分。如果你想要两个文件并排对比起来，那么垂直分离就会非常有用。你可以对面板进行无限细分，虽然这种嵌套的功能很快就会减少。你也可以将文件从其他的窗口拖入其它编辑器的面板，或者从一个面板拖到另外一个面板。关掉最近的面板选项卡会造成整个面板都消失。
The Gutter
信息槽
The gutter is used to convey information about your code. Perhaps the most obvious feature of the gutter is that small color swatches and image icons are displayed there alongside corresponding lines of code that refer to those visual resources. The gutter is also used to set breakpoints, facilitate code-folding, and display scope indicators. All of these features are covered in more detail in subsequent sections and chapters.
信息槽是来传递你的代码信息的。或许信息槽最明显的特点就是小色卡，还有沿着代码行边的图标，这些都是可以看得见的资源。信息槽也可以用来设置断点，代码折叠，还有作用域指示器。所有这些更加详细的特点都在随后的章节和后面的部分中。
The Marker Bar
标记栏
Along the right side of the Editor is the marker bar. The marker bar is used to indicate the location of important lines in your source files. For example, the marker bar highlights warnings and compile-time errors in your Java or XML files. The marker bar also shows you uncommitted changes, search results, and the locations of bookmarks.
沿着编辑器的右边的东西是标记栏。标记栏用来指出你的文件的重要行的位置。比如，在你的Java或者XML文件中，标记栏的高亮警示和编译时间错误。标记栏也会显示未提交的变化，查找结果还有书签的位置。
The marker bar does not scroll like the gutter does; rather, the colored ticks on the marker bar are positioned relative to the length of the file. Clicking a colored tick in the marker bar immediately jumps you to that location in the file. Practice using the marker bar by clicking some of its colored ticks now.
标记栏不能像信息槽一样可以滚动。当然，在标记栏上的彩色记号位于和文件长度相关的位置。点击在标记栏中的一个彩色记号就会立刻跳到你所要去的位置。现在开始联系通过点击一些彩色的记号来使用标记栏。
Tool Buttons
工具按钮
You’ve already seen the Project tool window, displayed in the left pane by default. To see a list of all the tool windows, choose View ➤ Tool Windows from the main menu bar. Now look carefully along the left, right, and bottom margins of the IDE. There you will find tool buttons that correspond to many of the tool windows. Notice that some of these tool buttons are also labeled with a number, which is used in combination with the Alt (Cmd on Mac) key to toggle that tool button’s corresponding tool window open/closed. Experiment with clicking the tool buttons now to practice this skill. Also practice using the keyboard shortcuts Alt+1 | Cmd+1, Alt+2 | Cmd+2, Alt+3 | Cmd+3, and so forth to toggle the tool windows open/closed.
你已经看到了工程工具窗口，它默认在面板的左边。为了看到所有工具窗口的列表，在主菜单栏中选择View->Tool Woindows。现在仔细的沿着IDE的左右和底部仔细查看。你会发现很多与工具窗口一致的工具按钮。能注意到这些工具按钮也是用数字标记的，这主要是为了能方便的使用快捷键来触发工具窗口的开闭，快捷键是用Alt（Mac是CMD）+数字键。现在点击工具按钮来练习这项技能。也可以联系使用键盘快捷键Alt+1|cmd+1，Alt+2|cmd+2，Alt+3|cmd+3，来开关窗口。
When a tool window is open, the corresponding tool button is dark gray, indicating that it is depressed. Notice that the tool buttons are located in the corners of the margins. For example, the default position of the Project tool button is in the upper corner of the left margin, while the Favorites tool button is located by default in the lower corner of the left margin. Side panes (left, bottom, and right) may be shared by up to two tool windows at a time.
当一个工具窗口打开的时候，相应的工具按钮是暗灰色的，表明它被按下去了。注意位于边缘角落里的工具按钮。例如，默认的工程工具按钮在左边的上面的角落里。，然而收藏夹工具按钮默认在左边的下面的角落里。在同一时间里，侧面面板可能会被两个以上的窗口共享。
To see how side panes may be shared, open both the Favorites and the Project tool windows. Notice that the Favorites and Project tool buttons are located in opposing corners of the same margin. Attempting to share a side pane between two tool windows whose corresponding tool buttons are located in the same corner will not work. For example, the Project and Structure tool windows cannot be displayed simultaneously—at least not in Android Studio’s default configuration.
为了看到侧面面板是如何共享使用的，打开收藏夹和工程工具窗口。注意到收藏夹和工程工具按钮位于同一侧的相反的角落里。尝试着让两个工具窗口使用同一侧的面板，这两个工具窗口的按钮在同一个角落是不能工作的。例如工程工具窗口和结构工具窗口时不能同时出现的，至少在Android Studio中的默认配置中是这样的。
Default Layout
默认布局
Don’t confuse default layout in Android Studio with layouts in the Android SDK. A default layout is a specific set of tool windows clustered around the Editor. Android Studio is configured out-of-the-box with a default layout that shows the Project tool window in the left pane. This is the layout displayed previously in Figure 2-1.
不要对Android Studio中的Android SDK布局感到混乱。一个默认的布局是环绕在编辑器周围的一系列具体的工具窗口。Android Studio被设置为打开就可使用的默认布局，这个默认布局就显示了左边面面板的工程工具窗口。如图2-1，这是一个预先已经显示的布局。
Let’s examine the Window menu in the main menu bar. The first two menu items are Store Current Layout as Default, and Restore Default Layout. The Restore Default Layout action is typically used when the IDE becomes overcrowded, or you just want to clear the slate and return to a familiar layout. You may also customize your default layout by opening and closing whichever tool windows you like, resizing and/or repositioning them, and then setting that new layout as the default by selecting Store Current Layout as Default.
让我们测试一下在主菜单栏中的窗口菜单吧。前两个菜单的主题默认是Store Current Layout(存储当前布局)和Restore Default Layout(重置默认布局)。通常当IDE被挤满的时候就会启用Default Layout操作，或者是在你想要清理界面，回到自己熟悉的布局的时候也会启用这个操作。你也通过打开或者关闭任何你喜欢的工具窗口来自定义你自己的默认布局。重置它们，然后设置新的布局作为默认布局，这个操作要选择Store Current Layout Default才能完成。
REPOSITIONING TOOL BUTTONS
As mentioned, the Project and Structure tool-windows can’t be displayed simultaneously because theircorresponding tool-buttons are located in the same corner. However, you can move any tool-button to anycorner you want. Drag-and-drop the Structure tool button to the bottom corner of the left margin. Now, togglethe Project and Structure tool-windows open by using either the keyboard shortcuts Alt+1 | Cmd+1 andAlt+7 | Cmd+7 or by clicking their tool buttons. Because we moved their tool buttons to opposing corners,the Project and Structure tool windows may now share the same side pane and be displayed simultaneously.
就像上面提到过的一样，Project和Structure工具窗口不能同时显示，因为它们相应的工具按钮位于相同的角落。然而，你可移动任何工具按钮到任何你想要的角落。拖放Structure工具按钮到左边底部的角落里。现在，使用快捷键ALt+1|cmd +1和Alt+7|cmd+7或者点击它们的工具按钮来打开Project和Structure工具窗口，因为我们把它们的工具按钮移动到了相反的角落。Project和Structure工具窗口现在可以出现在面板的同一边而且可以同时出现了。
Navigation Tool Windows
导航工具窗口
This section discusses tool windows that are used specifically for navigation: Project, Structure, Favorites, TODO, and Commander. Table 2-1 lists the function of each of these navigation tool windows. Subsequent chapters cover many of the other tool windows.
这一部分我们讨论对于操作的工具窗口。就像图2-1列出来的那样，列出了每个操作工具窗口的功能：Project,Structure,Favorities,TODO,Commander。随后的章节会涵盖其他的工具窗口。
Table 2-1. Navigation Tool Windows
Tool Window PC Keys Mac Keys Function
Project Alt+1 Cmd+1 Allows you to navigate
Favorites Alt+2 Cmd+2 Displays favorites, bookmarks, and breakpoints
Structure Alt+7 Cmd+7 Presents a hierarchical tree of the objects or elements in the current file
Commander Similar to the Project tool window, but allows for easy management of files
TODO Displays a list of all the active TODOs in a project
The Project Tool Window
工程工具窗口
We find the Project tool window to be the most useful of navigation tool windows because it combines wide scope with relatively easy access. To appreciate the power and scope of the Project tool window, you may want to set the window’s mode to Project. There are three modes; Project, Packages, and Android. By default, Android Studio will set the mode to Android. Android and Project are the most useful modes, though the Android mode may hide certain directories from you. The mode setting combo-box is located at 90 degrees and adjacent to the Project tool button in the upper left corner of the IDE.
我们发现工程工具窗口(Project tool window)是最有用的操作工具窗口，因为它范围宽泛，可以轻松访问。为了领会Project tool window的功能和范围，你可能想要设置工程的窗口模式。主要有三个模式：Project，Package，Android。默认情况下，Android Studio会设置为Android模式。Android和Project模式是最常用的模式，尽管Android模式对你隐藏了某些目录。这个模式设置复合框位于90度方向，挨着Project tool按钮，在IDE的左上角。
The Project tool window provides a simple tree interface with files and nested directories that you can toggle. The Project tool window gives you an overview of all the packages, directories, and files in your project. If you right-click (Ctrl-click on Mac) a file in the Project tool window, a context menu appears. There are three important menu items in this context menu: Copy Path, File Path, and Show in Explorer. Clicking Copy Path copies the operating system’s absolute path to this file to the clipboard. Clicking File Path displays the path as a stack of directories, terminating with the file on top, and clicking any of these directories opens them in the operating system. Clicking Show in Explorer shows the file in a new window of your operating system. See Figure 2-3.
工程工具窗口提供了一个简单的树形文件和嵌套的目录接口，你可以切换。工程工具窗口给了你一个你工程中的所有包，目录和文件的视图。如果你在Project tool window中右击（在mac中是Ctrl）一个文件，一个快捷菜单就会出现。在这个快捷菜单中有三个重要的菜单选项：Copy Path（复制路径），File Path（文件路径），show in Explorer（在浏览器中显示）。点击Copy Path就会复制文件的绝对路径到剪切板。点击File Path就会显示目录的树状图，顶部是文件的末尾，点开这些目录中的任何一个都可以在操作系统中打开。点击Show in Exploer文件就会在你的操作系统中的一个新的窗口中打开。如图2-3：
The Structure Tool Window
结构工具窗口
The Structure tool window displays a hierarchy of elements in your file. When the Editor is displaying a Java source file such as MainActivity.java, the Structure tool window displays a tree of elements such as fields, methods, and inner classes. When the Editor is displaying an XML file such as activity_main.xml, the Structure tool window displays a tree of XML elements. Clicking any element in the Structure tool window immediately moves your cursor to that element in the Editor. The Structure tool window is particularly useful for navigating among elements in large source files. Practice this skill by opening the Structure tool window and navigating among the elements of both MainActivity.java and activity_main.xml. See Figure 2-4.
结构工具窗口显示了你的文件的层级。当编辑器显示了一个java文件，比如是MainActivity.java，结构窗口工具（Structure tool windows）显示了一个像域，方法，和内部类这样的层级。当编辑器显示了一个XML文件，比如是activity_main.xml，Structure tool window显示了一个XML文件的树状层级。点击Structure tool windows中的任意一个元素，迅速移动光标到那个元素。Structure tool window在大量的资源文件中尤其作用巨大。操作activity_main.xml文件和MainActivity.java文件来练习这项技能。如图2-4所示：
The Favorites Tool Window
收藏夹工具窗口
When developing a feature (or debugging a bug) in Android, you will likely create or modify several related files. Moderately complex Android projects may contain hundreds of individual files, so the ability to group related files is useful indeed. The Favorites tool window contains favorites that allow you to logically group references to related files that might otherwise be physically located in completely different parts of your project. Make sure that both the MainActivity.java and activity_main.xml files are loaded as tabs in the Editor. Now right-click (Ctrl-click on Mac) either tab in the Editor and select Add All to Favorites from the context menu. In the Input New Favorites list Name field, type main and press OK. If the Favorites tool window is not open, activate it now by toggling Alt+2 | Cmd+2. Expand the favorites item called main, and double-click one of the files listed there in to open/activate it.
当在Android中开发一个特性（或者调试一个bug）的时候，你可能会创建或者修改很多相关联的文件。一个规模适中的Android工程都可能包含上百个单独的文件，因此分组处理相关联的文件是非常有必要的。收藏夹工具窗口包含你的个人收藏，这些个人收藏允许你有条理的分组管理相关联的文件，这些文件可能是完全不同于你在物理设备中的位置。确保MainActivity.java和activity_main.xml文件都被作为选项卡装载到你的编辑器中。现在在编辑器中的两个选项卡任选其一右击（Mac中是Ctrl），然后从快捷菜单中选择Add All to Favotites。在Input New Favorites列出的命名域中键入main然后点击OK。如果收藏夹工具窗口没有打开，按Alt+2|cmd+2打开。展开名为main的收藏夹主题，双击列出的其中一个文件来打开它。
Just as the Favorites window allows you to navigate immediately to any particular file or groups of files, bookmarks allow you to navigate immediately to any particular line in a file. Position your cursor on any line in MainActivity.java. Now press F11 (F3 on Mac). This action creates or removes a bookmark in any source file, including XML files. Notice both the checkmark in the gutter and the black tick in the marker bar indicating the new bookmark. To view the bookmark you just created, toggle open the bookmarks in the Favorites tool window.
就像收藏夹窗口允许你能比较直接的操纵某个文件或者某组文件，书签允许你快速的操作文件的中的某一行。把你的光标放到文件MainActivity.java中的任意一行。现在按F11(Mac中是F3)。这个操作会创建或者删除文件中的一个书签，包括.XML文件。当增添一个新的书签的时候，注意信息槽中的钩形符号和在标记栏中的黑色记号。为了看见你创建的新书签，在收藏夹工具窗口总打开书签。
Note On a PC, if F11 does not seem to be responding, check to make sure that the F-Lock key isactivated on your keyboard.
注意：在电脑中，如果按F11没有响应，检查一下你的键盘的F键是不是被锁住了。
Breakpoints are used for debugging. Unlike bookmarks, which may be set in any file, you need to be in a Java source file in order to set a breakpoint. Open MainActivity.java and click in the gutter next to the following line of code: setContentView(R.layout.activity_main); You will notice that a red circle now occupies the gutter and that the line is also highlighted red. Breakpoints can be set only on executable lines of code; trying to set a breakpoint on a comment line, for example, will not work. To view your newly created breakpoint, toggle open the Breakpoints tree in the Favorites tool window. There are several more interesting things you can do with breakpoints, and we discuss breakpoints at length in Chapter 12, which is devoted to debugging.
断点被用来程序调试。不像书签，可以在任何文件中设置。断点只能在java文件中设置。打开MainActivity.java文件，然后在代码setContentView(R.layout.activity_main)前的信息槽中点击，你会看到这一行的信息槽中出现了一个红点，而且这一行都变成红色的了。断点仅仅能被设置在可执行代码的那一行。为了看到你最新建立的断点，在收藏夹共苦窗口中打开端点树。你可以用断点做很多有趣的事情，我们将会在12章详细的讨论断点的问题，断点只是用来调试程序的。
