drawRect not being called for NSTableView cell view

Question

I have a view-based NSTableView with my custom view and the normal NSTextField in it. The custom view's background colour should change when a user clicks and it doesn't work because drawRect is not being called. I don't understand why really. Here's the delegate method and custom view code.

MyController

- (void)didAddLabel:(id)sender {
    CustomLabel *label = (CustomLabel *)sender;

    NSTableRowView *aaa = [_tableView rowViewAtRow:_tableView.selectedRow makeIfNecessary:NO];
    MyCustomView *hello = [((NSTableCellView*)[aaa viewAtColumn:0]).subviews objectAtIndex:0];

    [hello setBackgroundColor:[label nscolor]];
    NSLog(@"Background colour is %@", [hello backgroundColor]);
    [hello setNeedsDisplay:YES];
}

My view

class MyCustomView: NSView {

    var backgroundColor :NSColor  = NSColor.purpleColor()

    override func drawRect(dirtyRect: NSRect) {
        NSLog("In here")
        backgroundColor.setFill()
        NSRectFill(dirtyRect)
    }
}

Observations: 1) the drawRect is only called upon init of the app. 2) The NSLog row contains the new/selected colour however the background does not change from purple.

Question: why isn't drawRect: called after setNeedsDisplay:?

.and you're definitely returning your custom NSTableCellView subclass to the table in the appropriate places i.e. you've made sure that what you're casting to your MyCustomView is actually said class? — Jay
Thanks for that insight. The view actually had index 1 instead of 0. You may post your answer. — H.Rabiee

Dev Sanghani Dev Sanghani · Accepted Answer · 2016-05-10T10:44:01

drawRect: is only called if you don't have layer backing turned on. Are any of the parent views / this view have wantsLayer = YES or have a CALayer assigned to it? In that case, you'll have to use updateLayer: since all children of a layer-backed view are automatically layer-backed.

drawRect not being called for NSTableView cell view

MyController

My view

1 Answers