是什么原因导致白色边框应用于系统菜单中显示的NSProgressIndicator？

Question

当我在执行动作时创建NSProgressIndicator并使用NSStatusItem's -setView:方法在菜单栏区域中显示它时会发生这种情况:

混乱的NSProgressIndicator示例http://cl.ly/l9R/content

是什么原因导致显示此边框,如何删除它？预期的结果是控件是透明的.

这是我正在使用的代码:

NSProgressIndicator *progressIndicator = [[NSProgressIndicator alloc] init];

[progressIndicator setBezeled: NO];
[progressIndicator setStyle: NSProgressIndicatorSpinningStyle];
[progressIndicator setControlSize: NSSmallControlSize];
[progressIndicator sizeToFit];
[progressIndicator startAnimation: self];
[statusItem setView: progressIndicator]; // statusItem is an NSStatusItem instance
...
[statusItem setView: nil];
[progressIndicator stopAnimation: self];
[progressIndicator release];

Answer 1

不要缩放NSProgressIndicator虽然它也是一个NSView.创建一个精确调整大小的新视图,在该视图中定位状态指示器,并将封闭视图传递给-[NSStatusItem setView:].这是我的实施.

在NSStatusItem+AnimatedProgressIndicator.m,

- (void) startAnimation {

    NSView *progressIndicatorHolder = [[NSView alloc] init];

    NSProgressIndicator *progressIndicator = [[NSProgressIndicator alloc] init];

    [progressIndicator setBezeled: NO];
    [progressIndicator setStyle: NSProgressIndicatorSpinningStyle];
    [progressIndicator setControlSize: NSSmallControlSize];
    [progressIndicator sizeToFit];
    [progressIndicator setUsesThreadedAnimation:YES];

    [progressIndicatorHolder addSubview:progressIndicator];
    [progressIndicator startAnimation:self];

    [self setView:progressIndicatorHolder];

    [progressIndicator center];

    [progressIndicator setNextResponder:progressIndicatorHolder];
    [progressIndicatorHolder setNextResponder:self];

}

- (void) stopAnimation {

    [self setView:nil];

}

- (void) mouseDown:(NSEvent *) theEvent {

    [self popUpStatusItemMenu:[self menu]];

}

- (void) rightMouseUp:(NSEvent *) theEvent {}
- (void) mouseUp:(NSEvent *) theEvent {}
…

我添加了一个自定义方法-[NSView center],它执行以下操作:

@implementation NSView (Centering)

- (void) center {

    if (![self superview]) return;

    [self setFrame:NSMakeRect(

        0.5 * ([self superview].frame.size.width - self.frame.size.width),
        0.5 * ([self superview].frame.size.height - self.frame.size.height), 

        self.frame.size.width, 
        self.frame.size.height

    )];

}

@end