[英]How to set up an NSTextView programmatically with explicit NSLayoutManager, NSTextStorage, NSTextContainer?
按照蘋果文檔,我試圖通過它的兩個構造函數方法設置一個簡單的NSTextView
。
我將下面的代碼放在內容視圖的視圖控制器的viewDidAppear
方法中。 textView 是NSTextView
一個實例, frameRect 是內容視圖的框架。
以下 Swift 代碼有效(為我提供了一個可編輯的 textView,文本顯示在屏幕上):
textView = NSTextView(frame: frameRect!)
self.view.addSubview(textView)
textView.textStorage?.appendAttributedString(NSAttributedString(string: "Hello"))
以下不起作用(文本視圖不可編輯且屏幕上不顯示文本):
var textStorage = NSTextStorage()
var layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)
var textContainer = NSTextContainer(containerSize: frameRect!.size)
layoutManager.addTextContainer(textContainer)
textView = NSTextView(frame: frameRect!, textContainer: textContainer)
textView.editable = true
textView.selectable = true
self.view.addSubview(textView)
textView.textStorage?.appendAttributedString(NSAttributedString(string: "Hello more complex"))
我在第二個例子中做錯了什么? 我正在嘗試遵循 Apple 的“Cocoa Text Architecture Guide”中給出的示例,他們討論了通過顯式實例化其輔助對象網絡來設置NSTextView
。
您需要保留對您創建的NSTextStorage
變量的引用。 我不太確定這一切的機制,但看起來文本視圖只保留對其文本存儲對象的弱引用。 一旦這個對象超出范圍,它就不再可用於文本視圖。 我想這符合 MVC 設計模式,其中視圖(在這種情況下為NSTextView
)意味着獨立於它們的模型( NSTextStorage
對象)。
import Cocoa
@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
@IBOutlet weak var window: NSWindow!
var textView: NSTextView!
var textStorage: NSTextStorage! // STORE A REFERENCE
func applicationDidFinishLaunching(aNotification: NSNotification) {
var view = window.contentView as NSView
textStorage = NSTextStorage()
var layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)
var textContainer = NSTextContainer(containerSize: view.bounds.size)
layoutManager.addTextContainer(textContainer)
textView = NSTextView(frame: view.bounds, textContainer: textContainer)
textView.editable = true
textView.selectable = true
view.addSubview(textView)
textView.textStorage?.appendAttributedString(NSAttributedString(string: "Hello more complex"))
}
}
在 Xcode 12.4 下測試。 在游樂場:
import Cocoa
import AppKit
let textViewFrame = CGRect(x: 0, y: 0, width: 250, height: 90)
let textStorage = NSTextStorage()
var layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)
var textContainer = NSTextContainer(containerSize: textViewFrame.size)
layoutManager.addTextContainer(textContainer)
let textView = NSTextView(frame: textViewFrame, textContainer: textContainer)
textView.isEditable = true
textView.isSelectable = true
textView.textColor = NSColor.red
textView.string = "Why is this so complicated..."
#import <Cocoa/Cocoa.h>
@interface TextViewController : NSObject {
NSLayoutManager *secondLayout;
IBOutlet NSSplitView *columnView;
IBOutlet NSTextView *bottomView;
}
- (IBAction) addColumn: (id)sender;
@end
#import "TextViewController.h"
@implementation TextViewController
- (void)awakeFromNib
{
NSTextStorage *storage = [bottomView textStorage];
secondLayout = [NSLayoutManager new];
[storage addLayoutManager: secondLayout];
[secondLayout release];
[self addColumn: nil];
[self addColumn: nil];
}
- (IBAction) addColumn: (id)sender
{
NSRect frame = [columnView frame];
NSTextContainer *container = [[NSTextContainer alloc]
initWithContainerSize: frame.size];
[container setHeightTracksTextView: YES];
[container setWidthTracksTextView: YES];
[secondLayout addTextContainer: container];
[container release];
NSTextView *newView = [[NSTextView alloc] initWithFrame: frame
textContainer: container];
[columnView addSubview: newView];
[newView release];
}
@end
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