MacOS Swift应用点击添加标签功能代码编译通过但崩溃求助

Hey Marco, let's dig into why your code is crashing and fix it step by step. I spotted a few key issues that are causing the crash and preventing your text fields from showing up properly:

1. Undefined location Variable #

Your code references self.location but never actually retrieves the mouse click position from the NSEvent. This is definitely causing a crash because the variable doesn't exist. Instead, you need to get the click location directly from the event passed to the monitor closure.

2. Misused @IBOutlet for the Text Field Array #

@IBOutlet is meant for connecting UI elements from Storyboard/XIB files to your code. Since you're creating text fields programmatically, you don't need this annotation—just declare a regular array to hold your text fields. Using @IBOutlet here can lead to unexpected memory or initialization issues.

3. Forgetting to Add Text Fields to the View #

Even if you create the NSTextField instances, they won't appear (and might cause memory-related crashes) unless you add them as subviews to your window's content view.

4. Redundant count Variable #

You're manually tracking a count variable, but you can just use here2.count directly—this avoids synchronization issues where count might not match the actual array size.

Fixed Code #

Here's the revised, crash-free version of your code with explanations in comments:

// Remove @IBOutlet since we're creating text fields programmatically
var here2 = [NSTextField]()

override func viewDidLoad() {
    super.viewDidLoad()
    // Set up the mouse event monitor in a proper lifecycle method
    setupMouseClickMonitor()
}

func setupMouseClickMonitor() {
    NSEvent.addLocalMonitorForEvents(matching: .leftMouseDown) { [weak self] event in
        guard let self = self else { return event }
        
        // Get the click position relative to the window's content view
        let clickLocation = event.locationInWindow
        // Convert to the view's coordinate system for accurate positioning
        let viewLocation = self.view.convert(clickLocation, from: nil)
        
        // Check if the click is within your desired bounds
        if viewLocation.x < 700 && viewLocation.y < 750 {
            // Create a new text field
            let newTextField = NSTextField()
            // Set position and size (adjust size as needed)
            newTextField.frame = CGRect(origin: viewLocation, size: CGSize(width: 80, height: 24))
            // Set text to the current array count (no need for a separate variable)
            newTextField.stringValue = String(self.here2.count)
            // Make the text field visible (default style is hard to see)
            newTextField.borderStyle = .lineBorder
            newTextField.drawsBackground = true
            newTextField.backgroundColor = .white
            
            // Add the text field to the view so it renders on screen
            self.view.addSubview(newTextField)
            // Store it in the array for future reference
            self.here2.append(newTextField)
            
            print("count is: \(self.here2.count)")
        }
        return event
    }
}

Key Fixes Explained: #

• [weak self] in the closure: Prevents retain cycles that could cause memory leaks or crashes over time.
• Proper location retrieval: Uses event.locationInWindow and converts it to the view's coordinate system for accurate positioning.
• Added view insertion: self.view.addSubview(newTextField) ensures the text field is rendered on screen.
• Removed redundant count variable: Uses here2.count directly to keep track of the number of text fields.
• Visible text field setup: Added border and background so you can actually see the text field when it's created.

内容的提问来源于stack exchange，提问作者marco