Is there any way to add mouseOver events to a tableView in cocoa? - objective-c

Question

I want to make my tableView act like this:
When the mouse swipe over a certain row, the row will be highlighted, just like the mouseOver event of a button

Answer 1

It took me some time to work on it based on this hint.
It works for me, correct me if I'm wrong.
Tested with Swift 3.0.2 on macOS 10.12.2 and Xcode 8.2.1
//
// Created by longkai on 30/12/2016.
// Copyright (c) 2016 xiaolongtongxue.com. All rights reserved.
//
import Cocoa
class InboxTableCellView: NSTableCellView {
// MARK: - Outlets
#IBOutlet weak var title: NSTextField!
#IBOutlet weak var sender: NSTextField!
#IBOutlet weak var time: NSTextField!
#IBOutlet weak var snippet: NSTextField!
// MARK: - Mouse hover
deinit {
removeTrackingArea(trackingArea)
}
private var trackingArea: NSTrackingArea!
override func awakeFromNib() {
super.awakeFromNib()
self.trackingArea = NSTrackingArea(
rect: bounds,
options: [NSTrackingAreaOptions.activeAlways, NSTrackingAreaOptions.mouseEnteredAndExited,/* NSTrackingAreaOptions.mouseMoved */],
owner: self,
userInfo: nil
)
addTrackingArea(trackingArea)
}
override func draw(_ dirtyRect: NSRect) {
super.draw(dirtyRect)
NSColor(red: 0.96, green: 0.96, blue: 0.96, alpha: 1.00).set()
// mouse hover
if highlight {
let path = NSBezierPath(rect: bounds)
path.fill()
}
// draw divider
let rect = NSRect(x: 0, y: bounds.height - 2, width: bounds.width, height: bounds.height)
let path = NSBezierPath(rect: rect)
path.fill()
}
private var highlight = false {
didSet {
setNeedsDisplay(bounds)
}
}
override func mouseEntered(with event: NSEvent) {
super.mouseEntered(with: event)
if !highlight {
highlight = true
}
}
override func mouseExited(with event: NSEvent) {
super.mouseExited(with: event)
if highlight {
highlight = false
}
}
}

Answer 2

You need to create a subclass and use tracking areas. That's what buttons do to track mouse hovering.
There's an Apple Sample Code that does exactly what you need - highlighting rows on hover:
HoverTableDemo
It's been thoroughly discussed in WWDC 2011 Session 120

Answer 3

(Ignoring the "Mouse Over is bad GUI" sermon (which you'll ignore anyway… ;-))
#import "MoTableView.h"
#implementation MoTableView
{
NSUInteger mouseRow;
NSRect mouseRowFrame;
}
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code here.
mouseRow = -1;
}
return self;
}
- (void)awakeFromNib
{
[self.window setAcceptsMouseMovedEvents:YES];
}
- (void)drawRect:(NSRect)dirtyRect
{
[super drawRect:dirtyRect];
// Drawing code here.
[[NSColor redColor] set];
NSLogDebug(#"mouseRowFrame: %#", NSStringFromRect(mouseRowFrame));
NSFrameRectWithWidth(mouseRowFrame, 2.);
}
- (void)mouseMoved:(NSEvent *)theEvent
{
NSPoint mouseLocation = [theEvent locationInWindow];
NSPoint viewLocation = [self convertPoint:mouseLocation fromView:nil] ;
NSInteger row = [self rowAtPoint:viewLocation];
if (row != mouseRow) {
mouseRowFrame = [self rectOfRow:row];
[self setNeedsDisplay];
mouseRow = row;
}
}
#end