mainWindow更改时重绘NSView

Question

我想根据窗口是否聚焦来改变NSView的背景。

我发现了这个问题：Change NSView background color when window has focus

第一个答案正常，但窗口失去或获得焦点时不会触发重绘。

如何在mainWindow更改时触发重绘？

Answer 1

在NSWindow代表中：

func windowDidBecomeMain(notification: NSNotification) {
    let theView = ...
    theView.needsDisplay = true
}

func windowDidResignMain(notification: NSNotification) {
    let theView = ...
    theView.needsDisplay = true
}

在NSView子类中：

func drawRect(rect: NSRect) {
    if self.window.isMainWindow {
        // draw active appearance
    } else {
        // draw inactive appearance
    }
}

Answer 2

使用NSNotificationCenter的addObserver:selector:name:object:或addObserverForName:object:queue:usingBlock:以视图的NSWindowDidBecomeMainNotification作为NSWindowDidResignMainNotification的参数来监视window和object。