iOS7 QLPreviewController是否更改导航栏颜色？

如何在QLPreviewController中设置半透明属性我已经尝试了下面的代码，但它不起作用

  QLPreviewController *previewer = [[QLPreviewController alloc] init];
// Set data source
[previewer setDataSource:self];
[previewer setDelegate:self];
previewer.edgesForExtendedLayout = UIRectEdgeNone;
[previewer setCurrentPreviewItemIndex:index];
[self.navigationController.navigationBar setTranslucent:NO];
[self.navigationController setToolbarHidden:NO];
[[self navigationController] pushViewController:previewer animated:YES];

谢谢

注意：仅适用于iOS7。您可以使用：

UINavigationBar *navBar =  [UINavigationBar appearanceWhenContainedIn:[QLPreviewController class], nil];
[navBar setBackgroundImage:[UIImage imageNamed:@"navigation-bg-ios7.png"] forBarMetrics:UIBarMetricsDefault];

---

我已经试过了，而且效果很好。

Swift 3&4从2018年2月开始对我有效

import QuickLook

UINavigationBar.appearance(whenContainedInInstancesOf: [QLPreviewController.self]).setBackgroundImage(UIImage.init(color: primaryColor), for: .default)

这是扩展名中包含color func的图像

extension UIImage {

    //image with color
    convenience init?(color: UIColor) {
        let rect = CGRect(x: 0.0, y: 0.0, width: 1.0, height: 1.0)
        UIGraphicsBeginImageContext(rect.size)
        let path = UIBezierPath(rect: rect)
        color.setFill()
        path.fill()
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        self.init(cgImage: image!.cgImage!)
    }
}

extension UIImage {

    //image with color
    convenience init?(color: UIColor) {
        let rect = CGRect(x: 0.0, y: 0.0, width: 1.0, height: 1.0)
        UIGraphicsBeginImageContext(rect.size)
        let path = UIBezierPath(rect: rect)
        color.setFill()
        path.fill()
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        self.init(cgImage: image!.cgImage!)
    }
}