macOS Quick Cocoa App test with Swift

[mfram]

I created a simple Cocoa app to display the screen resolution. I verified that Swift makes it pretty easy to use the same method I used in Obj-C to create the same app. I will show you how similar they are.

The apps use text field outlets to display the values and button actions to trigger the fields getting set. I created a controller object as subclass of NSObject and instantiated that controller in the xib. The screenshot shows the app output.

I think the code looks pretty similar between Obj-C and Swift, so I think the new language and I will get along just fine. Well, so far. The bad news is that Xcode 6 crashed about 4 times while connecting Outlets and Actions in Swift. So all is not quite right with Xcode so far.

Sure enough, the Swift version is a little less verbose. That's nice!

Obj-C:

@interface ScreenResController : NSObject

- (IBAction)aButton:(NSButton *)sender;

@property (weak) IBOutlet NSTextField *frameXLabel;
@property (weak) IBOutlet NSTextField *frameYLabel;
@property (weak) IBOutlet NSTextField *visibleFrameXLabel;
@property (weak) IBOutlet NSTextField *visibleFrameYLabel;
@property (weak) IBOutlet NSButton *sButton;
@property (weak) IBOutlet NSButton *dButton;

@end

@implementation ScreenResController

- (void) awakeFromNib {
    [self aButton:self.sButton];
}

- (IBAction)aButton:(NSButton *)sender {
    NSScreen *ms = [NSScreen mainScreen];
    
    NSRect r = ms.frame;
    NSRect vf = ms.visibleFrame;
    
    if (sender == self.sButton)
    {
        self.frameXLabel.stringValue = [NSString stringWithFormat:@"%.1f", r.size.width];
        self.frameYLabel.stringValue = [NSString stringWithFormat:@"%.1f", r.size.height];
        
        self.visibleFrameXLabel.stringValue = [NSString stringWithFormat:@"%.1f", vf.size.width];
        self.visibleFrameYLabel.stringValue = [NSString stringWithFormat:@"%.1f", vf.size.height];
    }
    else
    {
        self.frameXLabel.doubleValue = r.size.width;
        self.frameYLabel.doubleValue = r.size.height;
        
        self.visibleFrameXLabel.doubleValue = vf.size.width;
        self.visibleFrameYLabel.doubleValue = vf.size.height;
    }
    
}
@end

And the Swift version:

import Cocoa

class SwiftController : NSObject
{
    @IBOutlet var frameX : NSTextField
    @IBOutlet var frameY : NSTextField
    @IBOutlet var visibleFrameX : NSTextField
    @IBOutlet var visibleFrameY : NSTextField
    
    @IBOutlet var sButton : NSButton
    @IBOutlet var dButton : NSButton
    
    override func awakeFromNib()
    {
        self.aButton(sButton)
    }
    
    @IBAction func aButton(sender : NSButton)
    {
        let ms = NSScreen.mainScreen()
        let f = ms.frame
        let vf = ms.visibleFrame
        
        if (sender === sButton)
        {
            self.frameX.stringValue = "\(f.size.width)"
            self.frameY.stringValue = "\(f.size.height)"
            self.visibleFrameX.stringValue = "\(vf.size.width)"
            self.visibleFrameY.stringValue = "\(vf.size.height)"
        }
        else
        {
            self.frameX.doubleValue = f.size.width
            self.frameY.doubleValue = f.size.height
            self.visibleFrameX.doubleValue = vf.size.width
            self.visibleFrameY.doubleValue = vf.size.height
        }
    }
    
}

 

[cognociente]

NSTextField!

In XCode6 and building a very similar example to yours given above and the compiler is forcing me to declare the text field as:
NSTextField! and not simply as NSTextField...

Any idea why that would be (I know it's making it an implicitly unwrapped optional) given that yours works without it?

 

[xanrov]

NSTextField

What beta version of Xcode 6 are you, guys,using ?
I tried successively beta 3 where I could write for an NSTextfield :

testfield.setStringValue(string) and it worked OK as anyone would expect.

Whereas with beta 4 I'm told that "setStringValue is not a member of NSTexrField" which seems to imply that Objective C was changed or than that version is buggy.

 

[cognociente]

I am using beta 4

Methods that begin with "set" do not seem to be available via the intellisense...

setStringValue() method has been replaced (relative to Objective-C) with a stringValue property from what I can see.

 

[xanrov]

NSTextField

I'm having a problem with this setValue() method:
let 'res' be the name of a Swift string and textField an instance of NSTextField :
If I write : textField.setValue(res) , the complier does'nt complain, builds OK but my app hangs when I trigger the method.
My app is an elementary applet with just 2 textFields and a button. I verified that the hanging comes from this very line.
How the deuce is the right Swift way of setting a String in an NSTextField ?

 

[xanrov]

NSTextField

Found out how to set a string in an NSTextField :

Just write : textField.stringValue = "string"

Must be the same for other types (Int, Double etc) or for other instances of View classes