How do I make an NSView move to the front of all NSViews

问题

I have a super view, which has 2 subviews. These subviews are overlapped.

Whenever i choose a view from a menu, corresponding view should become the front view and handle actions. i.e., it should be the front most subview.

acceptsFirstResponder resigns all work fine. But the mouse down events are sent to the topmost sub view which was set.

Regards, Dhana

回答1:

Here's another way to accomplish this that's a bit more clear and succinct:

[viewToBeMadeForemost removeFromSuperview];
[self addSubview:viewToBeMadeForemost positioned:NSWindowAbove relativeTo:nil];

Per the documentation for this method, when you use relativeTo:nil the view is added above (or below, with NSWindowBelow) all of its siblings.

回答2:

Another way is to use NSView's sortSubviewsUsingFunction:context: method to re-order a collection of sibling views to your liking. For example, define your comparison function:

static NSComparisonResult myCustomViewAboveSiblingViewsComparator( NSView * view1, NSView * view2, void * context )
{    
    if ([view1 isKindOfClass:[MyCustomView class]])    
        return NSOrderedDescending;    
    else if ([view2 isKindOfClass:[MyCustomView class]])    
        return NSOrderedAscending;    

    return NSOrderedSame;
}

Then when you want to ensure your custom view remains above all sibling views, send this message to your custom view's superview:

[[myCustomView superview] sortSubviewsUsingFunction:myCustomViewAboveSiblingViewsComparator context:NULL];

Alternatively, you can move this code to the superview itself, and send the message sortSubviewsUsingFunction:context: to self instead.

回答3:

using @Dalmazio's answer in a Swift 4 category that mimics the equivalent UIView method gives the following:

extension NSView {

    func bringSubviewToFront(_ view: NSView) {
            var theView = view
            self.sortSubviews({(viewA,viewB,rawPointer) in
                let view = rawPointer?.load(as: NSView.self)

                switch view {
                case viewA:
                    return ComparisonResult.orderedDescending
                case viewB:
                    return ComparisonResult.orderedAscending
                default:
                    return ComparisonResult.orderedSame
                }
            }, context: &theView)
    }

}

so, to bring subView to the front in containerView

containerView.bringSubviewToFront(subView)

unlike solutions which remove and re-add the view, this keeps constraints unchanged

回答4:

I was able to get this to work without calling removeFromSuperView

// pop to top
[self addSubview:viewToBeMadeForemost positioned:NSWindowAbove relativeTo:nil];

回答5:

Below given code should work fine..

    NSMutableArray *subvies = [NSMutableArray arrayWithArray:[self subviews]];//Get all subviews..

    [viewToBeMadeForemost retain]; //Retain the view to be made top view..

    [subvies removeObject:viewToBeMadeForemost];//remove it from array

    [subvies addObject:viewToBeMadeForemost];//add as last item

    [self setSubviews:subvies];//set the new array..

回答6:

You can achieve this by just adding the view again; it will not create another instance of it.

[self addSubview:viewToBeMadeForemost];

You can Log the number of subviews before and after this line of code is executed.

回答7:

To move a view to the front, it must be placed as the last element in the subviews array. Here's a Swift 3.0 solution:

func bringChildToFrontWith(viewIdentifier: Int) {
    var subViewArray = self.subviews // Apple docs recommend copying subViews array before operating on it, as it "can be changed at any time"
    for ix in 0 ..< subViewArray.count {
        if let childView = subViewArray[ix] as? MyViewSubClass {
            if childView.myViewSubClassIdentifier == viewIdentifier {
                let topItem = subViewArray[ix];
                subViewArray.remove(at: ix)
                subViewArray.append(topItem)
                self.contentView.subviews = subViewArray
            }
        }
    }
}

回答8:

You might try this:

[viewToBeMadeFirst.window makeKeyAndOrderFront:nil];

来源：https://stackoverflow.com/questions/2872840/how-do-i-make-an-nsview-move-to-the-front-of-all-nsviews

标签

cocoa

nsview