Lập trình Wrox Professional Xcode 3 cho Mac OS part 32 pptx

2. Save the fi le in the project folder and let Interface Builder add it to the project. 3. Close the nib document in Interface Builder. 4. Localize the nib document in Xcode as described in the “ Localizing Files ” section of Chapter 6. TIP TO REMEMBER If your project already has .lproj folders (because other fi les have been localized), you can save your new fi le directly into the .lproj folder of the appropriate language. Xcode treats the nib document as if it has already been localized. You can skip the step of localizing the fi le, and jump right to adding new localizations. OPENING SISTER LOCALIZATIONS In addition to the obvious ways of opening a nib document — opening it from Xcode or the Finder, the File ➪ Open command, or the File ➪ Open Recent menu — Interface Builder has a shortcut for opening other localizations of the same fi le. The File ➪ Open Localization menu lists all of the other language variants of the currently active nib document. Interface Builder detects when a nib document is located in an .lproj localization folder. It then fi nds all sister .lproj folders containing the same document and adds them to this submenu. This allows you to quickly switch between localizations of the same fi le. The Open All command opens all localizations at once. CREATING OBJECTS The fi rst “ C ” of Interface Builder is creating objects. Objects are easy to create: drag an object from the library palette into your nib document or view window. Creating an object is as easy as dragging an instance out of the library item and dropping it into your nib document window, as shown in the middle in Figure 13 - 11. You can also drop a view object directly into a view window, as shown on the left in Figure 13 - 11 — as long as it ’ s an object appropriate for that view. Creating Objects ❘ 243 c13.indd 243c13.indd 243 1/21/10 3:36:40 PM1/21/10 3:36:40 PM Download at getcoolebook.com 244 ❘ CHAPTER 13 INTERFACE BUILDER Using either technique, subview objects can be inserted directly into the view hierarchy. When dropping into the nib document window, drop the object inside the appropriate view. When dropping a new object in a view window, it ’ s implied that the new object will be inserted into a container view, even if that container is just the window object. Interface Builder highlights and identifi es the container that will receive the new object. Figure 13 - 12 illustrates how the location of the drop determines which superview will receive the new object. In all cases, containers only accept certain object classes (or their subclasses). For example, you cannot add an arbitrary object (such as NSObject) inside a view container, no matter where you attempt to drop it. The library palette will only create objects in its repertoire. See the section “ Custom Classes ” later in this chapter to learn how to create objects with custom classes. Here are a few shortcuts and tricks for creating objects in Interface Builder: Create a new window by dragging a window object out of the library palette and dropping it anywhere on the screen. ➤ FIGURE 13-11 FIGURE 13-12 c13.indd 244c13.indd 244 1/21/10 3:36:41 PM1/21/10 3:36:41 PM Download at getcoolebook.com To create an unattached view (NSView, UIView, and so on) object, drag a new view object into the nib document window to create a top - level object. Double - click the new object to open it in a view window where you can edit its content. You cannot create a top - level Cocoa application menu bar object using the NSMenu object in the library palette. (It will create a menu bar, but it won ’ t be the application menu bar.) Should you ever need to create one, use the Cocoa Main Menu template to create a new nib document that contains a full application menu bar object, copy it into your nib document, and then edit it as desired. COPYING, DUPLICATING, AND DELETING OBJECTS Another way of creating an object that should not be overlooked is to duplicate an existing object. This can save a lot of time when creating groups of similarly confi gured objects. The following actions create copies or delete objects in your nib document: Edit ➪ Cut Edit ➪ Copy Edit ➪ Paste Edit ➪ Delete Delete key Edit ➪ Duplicate Option+drag Drag an object from one nib document to another Holding down the Option key while dragging objects, or selecting the Edit ➪ Duplicate command, duplicates the selected objects, inserting the copies wherever they are dropped or making them siblings of their originals, respectively. If you repeatedly use complex objects or layouts in your projects, you can save preconfi gured objects in the library palette. See the section “ Saving Custom Objects ” toward the end of this chapter. SELECTING OBJECTS Before you can examine or change the attributes of an object, you must select it. This sounds simple — and it usually is — but there is some subtlety to selecting objects in Interface Builder of which you ’ ll want to be aware. There are two places to select Interface Builder objects. All objects appear in the nib document window and can be selected there. View objects can optionally appear in a view window, approximately as they will appear in your application. Selecting a view object is equivalent to selecting the same object in the nib document window. ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ ➤ Selecting Objects ❘ 245 c13.indd 245c13.indd 245 1/21/10 3:36:50 PM1/21/10 3:36:50 PM Download at getcoolebook.com 246 ❘ CHAPTER 13 INTERFACE BUILDER Objects in the Nib Document Window Selecting objects in the nib document window is simple and straightforward: select the object or objects with which you want to work using any of the three view modes. The icon view only allows you to select top - level objects, and the browser mode only lets you select multiple objects within the same branch of the hierarchy. I tend to use the list view most of the time. All of the standard Mac OS X icon/list selection gestures work here: Click, Shift+click, Command+click, and dragging out a rectangle. Selecting a container object does not select any of the objects that it contains. If you want to edit the attributes of a view and all of its subviews simultaneously, you must explicitly select both the container view and its subview objects. The advantage of selecting objects in the nib document window is that they are unambiguous. The nib document window lists each and every object defi ned in that document. Of course, the nib document window is the only place you can select objects that don ’ t have a visual representation. The disadvantage is that it may sometimes be diffi cult to distinguish between different objects in the list. For example, a nib document that defi nes fi ve untitled radio - button objects simply shows fi ve identical radio - button icons, whereas in a view window, each radio button object appears as a radio button, at the position it will be in that window. See the “ Identity ” section to learn how to name objects so they are easier to fi nd in the nib document window. Object Order The order in which subobjects appear in the nib document window list defi nes their order in the nib document. Often the order of objects is completely immaterial. Within a view container, the order defi nes the Z - order of the subviews — the order in which the objects overlap. The fi rst object in the list will be behind all of the objects that come after it. You can reorder objects in the document window by dragging them to a new position in the list, or you can use any of these commands on view objects: Layout ➪ Send to Front (Option+Shift+Command+F) Layout ➪ Send to Back Layout ➪ Send Forward Layout ➪ Send Backwards Object order is different from object position (see the “ Moving and Resizing Objects ” section). View Objects View objects in the nib document window may also appear as “ themselves ” — an approximate representation of that class of view object at run time — in a separate view window. For example, a view window containing the menu of your application lets you see, select, and edit the contents of your menus, more or less as the menu items will appear in your application. A single NSView or UIView object will appear in a window where you can resize it, add subviews, and customize its appearance. If the view object is, itself, a window object, the view window represents that window object in the nib document. ➤ ➤ ➤ ➤ c13.indd 246c13.indd 246 1/21/10 3:36:51 PM1/21/10 3:36:51 PM Download at getcoolebook.com View objects do not have to appear in a view window. Any view window can be closed, tidying up your workspace. To reveal it again, double - click the view object in the nib document window. The view object, or the view window that contains it, will open again. This will also select the view object in the view window. Unless the view window is representative of an actual window object in the nib document, the view window is just a convenient container provided by Interface Builder. For example, the position of the view window that contains a menubar object is superfl uous. Selecting Multiple View Objects Select a single view object by clicking it. You can select multiple view objects by dragging out a selection rectangle. Any view objects whose position intersects the selection rectangle will be selected, as shown in Figure 13 - 13. When single - clicking an object, the selection can be modifi ed using one of the following keyboard modifi ers: Holding down the Shift key adds the object to the set of currently selected objects. Holding down the Command key toggles the selection of the object: an unselected object is selected (same as Shift), and a selected object is unselected. Selecting Interior View Objects Some objects, like tab and split pane views, are containers for other view objects. To select a container object, click any unoccupied region within the container. To select an object within the container, click directly over that object. Figure 13 - 14 shows two different selections: on the left, the button object contained in the box object is selected; on the right, the box object itself is selected. ➤ ➤ FIGURE 13-14 Selecting Objects ❘ 247 FIGURE 13-13 Sometimes, selecting a container is inconvenient or impossible (a split view with an invisible divider might not have any unoccupied region on which to click). Normally when you click a view object, Interface Builder selects the most specifi c object in the visual hierarchy at the clicked coordinate. This is the so - called “ inside out ” selection strategy. Holding down the Command key while clicking reverses this logic. Interface Builder selects the outermost container that occupies the clicked coordinate. In the example shown in Figure 13 - 14, c13.indd 247c13.indd 247 1/21/10 3:36:56 PM1/21/10 3:36:56 PM Download at getcoolebook.com 248 ❘ CHAPTER 13 INTERFACE BUILDER clicking the Can Get Smarter radio button selects that NSButton object. Holding down the Command key while clicking same button selects its enclosing NSBox object. Drilling Into View Objects Tables and many other kinds of nested views support a selection technique called drilling . The fi rst time you click the object, you select the container object. Single - click again, and the selection “ drills down ” into the object hierarchy. Using the table view object in Figure 13 - 15 as an example, imagine positioning your cursor over the middle Text Cell object. Clicking four times slowly — remember these are all single - click actions — produces the following selections: 1. The fi rst click selects the scroll view object. 2. The second click selects the table view object nested inside the scroll view. 3. The third click selects the second table column object of the table view. 4. The fourth click selects the text cell object used to draw the cells of the second column. FIGURE 13-15 c13.indd 248c13.indd 248 1/21/10 3:36:57 PM1/21/10 3:36:57 PM Download at getcoolebook.com The same technique works with the column header objects of the table. Most view objects that form a similar hierarchy can be drilled into, such as any scroll view. Of particular note is the cell object nested inside each control view object. It ’ s not always obvious, but every control view (button, slider, and so on) is actually two objects: a controller object and a cell object that provides its look and feel. Object Selection vs. Object Focus There ’ s a subtle difference between selecting a view object and having a view object that ’ s the current focus of Interface Builder. Click once to select a container object. Click again to make it the focus. Figure 13 - 16 shows the difference. On the left, the Box view object is selected. On the right, the box view has the current focus. For many commands, there ’ s no difference between these two states, but for some, notably Edit ➪ Paste, there ’ s a big difference. If there were two button objects on the clipboard, choosing the Edit ➪ Paste command while the box object was selected (left) would just paste two buttons into the window. If the box object is the focus (right), the Paste command would insert the two buttons inside, making them subviews of the box object. Adjusting the Selection A number of commands change the selection. When selecting and unselecting multiple objects, don ’ t neglect these perennial favorites: Edit ➪ Select All (Command+A) Edit ➪ Select None (Shift+Command+D) The following four commands let you shift the selection to a different object relative to the currently selected object, or objects: Tools ➪ Select Parent (Control+Command+ ↑) Tools ➪ Select Child (Control+Command+ ↓) Tools ➪ Select Previous Sibling (Control+Command+ ← ) Tools ➪ Select Next Sibling (Control+Command+ → ) The Tools ➪ Select Parent command selects the container object of the currently selected object or objects. Tools ➪ Select Child selects the fi rst object contained within the currently selected object. Taken together, these two commands allow you to either “ walk up ” or “ drill down ” into the object hierarchy. The Next and Previous Sibling commands shift the selection to the next, or previous, object in the same container object. These commands navigate by object order (Z - order), not position. ➤ ➤ ➤ ➤ ➤ ➤ Selecting Objects ❘ 249 FIGURE 13-16 c13.indd 249c13.indd 249 1/21/10 3:36:57 PM1/21/10 3:36:57 PM Download at getcoolebook.com 250 ❘ CHAPTER 13 INTERFACE BUILDER CONFIGURING OBJECTS Objects in Interface Builder wouldn ’ t be much use if you couldn ’ t bend and shape them to your needs. Most of your time in Interface Builder will be spent editing objects, and you have many different ways to do that. The overt aspects (visible text, placement, and size) of view objects can be manipulated directly: drag an object around to reposition it; double - click the text of an object to change it. Less obvious attributes, such as formatting options and bindings, are manipulated in the inspector palette. A few specialized commands also exist for aligning objects and grouping objects in containers. Moving and Resizing Objects An object, or a group of selected objects, can be repositioned in a view window simply by dragging it to another location, as shown in Figure 13 - 17. Depending on the layout, some objects may not be repositioned. For instance, an object in one half of a split view always occupies that entire space. It cannot be repositioned, because its location and size are determined by the split view. Altering the position of the split view or its divider is the only way to change that object ’ s position in the window. Interface Builder displays guidelines as an object is dragged. When the object is released, it “ snaps ” to nearest guideline. See the “ Guides ” section to fi nd out how to control these automatic guidelines or create your own. The arrow keys nudge the selected objects one pixel in any direction. Hold down the Shift key to nudge them 10 pixels at a time. Dragging the handles on the edge of an object resizes it. Some objects cannot be resized, or can only be resized in certain directions. For example, the height of a button is fi xed in Cocoa. You can only change its width. Using the resize handles, you can only resize one object at a time. TIP TO REMEMBER Holding down the Command and Options keys while resizing a container view, such as a window or box view, resizes its subviews too. The subviews are resized according to their resize behavior. This is the same effect that you get when resizing a container view using the Size inspector. Both the Size inspector and resize behavior are described later in the “Size” section. FIGURE 13-17 c13.indd 250c13.indd 250 1/21/10 3:36:58 PM1/21/10 3:36:58 PM Download at getcoolebook.com . for that view. Creating Objects ❘ 2 43 c 13. indd 243c 13. indd 2 43 1/21/10 3: 36:40 PM1/21/10 3: 36:40 PM Download at getcoolebook.com 244 ❘ CHAPTER 13 INTERFACE BUILDER Using either technique,. order), not position. ➤ ➤ ➤ ➤ ➤ ➤ Selecting Objects ❘ 249 FIGURE 13- 16 c 13. indd 249c 13. indd 249 1/21/10 3: 36:57 PM1/21/10 3: 36:57 PM Download at getcoolebook.com 250 ❘ CHAPTER 13 INTERFACE. Builder selects the outermost container that occupies the clicked coordinate. In the example shown in Figure 13 - 14, c 13. indd 247c 13. indd 247 1/21/10 3: 36:56 PM1/21/10 3: 36:56 PM Download at getcoolebook.com 248 ❘