Best way to change the background color for an NSView

问题

I'm looking for the best way to change the backgroundColor of an NSView. I'd also like to be able to set the appropriate alpha mask for the NSView. Something like:

myView.backgroundColor = [NSColor colorWithCalibratedRed:0.227f 
                                                   green:0.251f 
                                                    blue:0.337 
                                                   alpha:0.8];

I notice that NSWindow has this method, and I'm not a big fan of the NSColorWheel, or NSImage background options, but if they are the best, willing to use.

回答1:

Yeah, your own answer was right. You could also use Cocoa methods:

- (void)drawRect:(NSRect)dirtyRect {
    // set any NSColor for filling, say white:
    [[NSColor whiteColor] setFill];
    NSRectFill(dirtyRect);
    [super drawRect:dirtyRect];
}

In Swift:

class MyView: NSView {

    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)

        // #1d161d
        NSColor(red: 0x1d/255, green: 0x16/255, blue: 0x1d/255, alpha: 1).setFill()
        dirtyRect.fill()
    }

}

回答2:

An easy, efficient solution is to configure the view to use a Core Animation layer as its backing store. Then you can use -[CALayer setBackgroundColor:] to set the background color of the layer.

- (void)awakeFromNib {
   self.wantsLayer = YES;  // NSView will create a CALayer automatically
}

- (BOOL)wantsUpdateLayer {
   return YES;  // Tells NSView to call `updateLayer` instead of `drawRect:`
}

- (void)updateLayer {
   self.layer.backgroundColor = [NSColor colorWithCalibratedRed:0.227f 
                                                          green:0.251f 
                                                           blue:0.337 
                                                          alpha:0.8].CGColor;
}

That’s it!

回答3:

If you are a storyboard lover, here is a way that you don't need any line of code.

Add NSBox as a subview to NSView and adjust NSBox's frame as the same with NSView.

In Storyboard or XIB change Title position to None, Box type to Custom, Border Type to "None", and Border color to whatever you like.

Here is a screenshot:

This is the result:

回答4:

If you setWantsLayer to YES first, you can directly manipulate the layer background.

[self.view setWantsLayer:YES];
[self.view.layer setBackgroundColor:[[NSColor whiteColor] CGColor]];

回答5:

Think I figured out how to do it:

- (void)drawRect:(NSRect)dirtyRect {
    // Fill in background Color
    CGContextRef context = (CGContextRef) [[NSGraphicsContext currentContext] graphicsPort];
    CGContextSetRGBFillColor(context, 0.227,0.251,0.337,0.8);
    CGContextFillRect(context, NSRectToCGRect(dirtyRect));
}

回答6:

I went through all of these answers and none of them worked for me unfortunately. However, I found this extremely simple way, after about an hour of searching : )

myView.layer.backgroundColor = CGColorCreateGenericRGB(0, 0, 0, 0.9);

回答7:

edit/update: Xcode 8.3.1 • Swift 3.1

extension NSView {
    var backgroundColor: NSColor? {
        get {
            guard let color = layer?.backgroundColor else { return nil }
            return NSColor(cgColor: color)
        }
        set {
            wantsLayer = true
            layer?.backgroundColor = newValue?.cgColor
        }
    }
}

usage:

let myView = NSView(frame: NSRect(x: 0, y: 0, width: 100, height: 100))
print(myView.backgroundColor ?? "none")     //  NSView's background hasn't been set yet = nil
myView.backgroundColor = .red               // set NSView's background color to red color
print(myView.backgroundColor ?? "none")
view.addSubview(myView)

回答8:

Best Solution :

- (id)initWithFrame:(NSRect)frame
{
    self = [super initWithFrame:frame];
    if (self)
    {
        self.wantsLayer = YES;
    }
    return self;
}

- (void)awakeFromNib
{
    float r = (rand() % 255) / 255.0f;
    float g = (rand() % 255) / 255.0f;
    float b = (rand() % 255) / 255.0f;

    if(self.layer)
    {
        CGColorRef color = CGColorCreateGenericRGB(r, g, b, 1.0f);
        self.layer.backgroundColor = color;
        CGColorRelease(color);
    }
}

回答9:

Without doubt the easiest way, also compatible with Color Set Assets:

Swift:

view.setValue(NSColor.white, forKey: "backgroundColor")

Objective-C:

[view setValue: NSColor.whiteColor forKey: "backgroundColor"];

Interface Builder:

Add a user defined attribute backgroundColor in the interface builder, of type NSColor.

回答10:

In Swift:

override func drawRect(dirtyRect: NSRect) {

    NSColor.greenColor().setFill()
    NSRectFill(dirtyRect)

    super.drawRect(dirtyRect)
}

回答11:

Use NSBox, which is a subclass of NSView, allowing us to easily style

Swift 3

let box = NSBox()
box.boxType = .custom
box.fillColor = NSColor.red
box.cornerRadius = 5

回答12:

I tested the following and it worked for me (in Swift):

view.wantsLayer = true
view.layer?.backgroundColor = NSColor.blackColor().colorWithAlphaComponent(0.5).CGColor

回答13:

In Swift 3, you can create an extension to do it:

extension NSView {
    func setBackgroundColor(_ color: NSColor) {
        wantsLayer = true
        layer?.backgroundColor = color.cgColor
    }
}

// how to use
btn.setBackgroundColor(NSColor.gray)

回答14:

Have a look at RMSkinnedView. You can set the NSView's background color from within Interface Builder.

回答15:

In swift you can subclass NSView and do this

class MyView:NSView {
    required init?(coder: NSCoder) {
        super.init(coder: coder);

        self.wantsLayer = true;
        self.layer?.backgroundColor = NSColor.redColor().CGColor;
    }
}

回答16:

Just small reusable class (Swift 4.1)

class View: NSView {

   var backgroundColor: NSColor?

   convenience init() {
      self.init(frame: NSRect())
   }

   override func draw(_ dirtyRect: NSRect) {
      if let backgroundColor = backgroundColor {
         backgroundColor.setFill()
         dirtyRect.fill()
      } else {
         super.draw(dirtyRect)
      }
   }
}

// Usage
let view = View()
view.backgroundColor = .white

回答17:

This supports changing systemwide appearance (turning dark mode on or off) while the application is running. You can also set the background colour in Interface Builder, if you set the class of the view to BackgroundColorView first.


class BackgroundColorView: NSView {
    @IBInspectable var backgroundColor: NSColor? {
        didSet { needsDisplay = true }
    }

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        wantsLayer = true
    }

    required init?(coder decoder: NSCoder) {
        super.init(coder: decoder)
        wantsLayer = true
    }

    override var wantsUpdateLayer: Bool { return true }

    override func updateLayer() {
        layer?.backgroundColor = backgroundColor?.cgColor
    }
}

来源：https://stackoverflow.com/questions/2962790/best-way-to-change-the-background-color-for-an-nsview

标签

objective-c

macos

background-color

nsview