Question

我正在尝试使用渐变填充NSView。当窗口在背景中时，渐变应该具有较浅的颜色以匹配窗口的其余部分。下面的代码有很多工件：首次绘制窗口时，它会使用背景颜色绘制。调整窗口大小时，将使用前景色。当窗口移动到后面时，不会按预期使用背景颜色。我不应该使用isKeyWindow来完成这项任务吗？

- (void)drawRect:(NSRect)dirtyRect {

    if ([[self window] isKeyWindow]) {

        NSColor *startingColor = [NSColor colorWithCalibratedWhite:0.8 alpha:1.0];
        NSColor *endingColor = [NSColor colorWithCalibratedWhite:0.6 alpha:1.0];
        NSGradient* aGradient = [[NSGradient alloc]
                             initWithStartingColor:startingColor
                             endingColor:endingColor];
        [aGradient drawInRect:[self bounds] angle:270];

    } else {
        NSColor *startingColor = [NSColor colorWithCalibratedWhite:0.9 alpha:1.0];
        NSColor *endingColor = [NSColor colorWithCalibratedWhite:0.8 alpha:1.0];
        NSGradient* aGradient = [[NSGradient alloc]
                             initWithStartingColor:startingColor
                             endingColor:endingColor];
        [aGradient drawInRect:[self bounds] angle:270];
    }
    [super drawRect:dirtyRect];
}

Answer 1

我认为您所看到的行为是因为窗口不一定会重新绘制，因为它会获得或失去关键状态。我会尝试在窗口变为或重置密钥时强制更新窗口。类似的东西：

- (void) viewDidMoveToWindow
{
    if( [self window] == nil ) {
        [[NSNotificationCenter defaultCenter] removeObserver:self];
    }
    else {
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(forceUpdate)
                                                     name:NSWindowDidResignKeyNotification
                                                   object:[self window]];
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(forceUpdate)
                                                     name:NSWindowDidBecomeKeyNotification
                                                   object:[self window]];
    }
}

- (void) forceUpdate
{
    [self setNeedsDisplay:YES];
}

NSView与渐变填充？

1 个答案: