mouseEntered和mouseExited在NSImageView子类中未调用 [英] mouseEntered and mouseExited not called in NSImageView SubClass

问题描述

我创建了 NSImageView 的子类来捕获 mouseEntered 和 mouseExited 事件。
但是只有 mouseUp 和 mouseDown 事件被调用。如何捕获 NSImageView 子类中的 mouseEntered 和 mouseExited ？

I created a subclass of NSImageView to capture mouseEntered and mouseExited events. But only mouseUp and mouseDown events are getting called. How to capture the mouseEntered and mouseExited events in NSImageView subclass?

推荐答案

如果您想使用 mouseEntered：和 mouseExited：您需要使用 NSTrackingArea 。以下是 NSTrackingArea类参考的参考。

If You want to use mouseEntered: and mouseExited: You need to use NSTrackingArea. Here is reference NSTrackingArea Class Reference.

示例：

//Add this to Your imageView subclass

-(void)mouseEntered:(NSEvent *)theEvent {
    NSLog(@"Mouse entered");
}

-(void)mouseExited:(NSEvent *)theEvent
{
    NSLog(@"Mouse exited");
}

-(void)updateTrackingAreas
{ 
    if(trackingArea != nil) {
        [self removeTrackingArea:trackingArea];
        [trackingArea release];
    }

    int opts = (NSTrackingMouseEnteredAndExited | NSTrackingActiveAlways);
    trackingArea = [ [NSTrackingArea alloc] initWithRect:[self bounds]
                                                 options:opts
                                                   owner:self
                                                userInfo:nil];
    [self addTrackingArea:trackingArea];
}

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