我正在开发IOS,我使用以下代码设置navigationBar
的背景。
[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"bar-back"] forBarMetrics:UIBarMetricsDefault];
我想在navigationBar
和navigationBar
的中心添加一个图像,如下图所示。
如何在Objective-C的导航栏中心添加图像?
提前致谢。
设置导航标题视图如下所示
self.navigationItem.titleView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"img.png"]];
UIImage *img = [UIImage imageNamed:@"1.png"];
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
[imgView setImage:img];
// setContent mode aspect fit
[imgView setContentMode:UIViewContentModeScaleAspectFit];
self.navigationItem.titleView = imgView;
正如你所说的那样为应用程序设置一个图标。您可能希望为此展示整个应用程序的图标。
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"icon"]];
CGSize imageSize = CGSizeMake(40, 40);
CGFloat marginX = (self.navigationController.navigationBar.frame.size.width / 2) - (imageSize.width / 2);
imageView.frame = CGRectMake(marginX, 0, imageSize.width, imageSize.height);
[self.navigationController.navigationBar addSubview:imageView];
输出:
这里要提到的一件事是为UIImageView使用宽度为3。这很重要 - 如果它是2(或任何偶数),那么图像将是模糊的。设置clipToBounds = NO和contentMode = UIViewContentModeScaleAspectFill意味着图像将显示在图像视图的宽度(精细)之外,并且将正确比例。
UIImageView *imageView = [[UIImageView alloc]
initWithFrame:CGRectMake(0,0,3,44)];
imageView.contentMode = UIViewContentModeScaleAspectFill;
imageView.clipsToBounds = NO;
imageView.image = [UIImage imageNamed:@"navigation-logo"];
controller.navigationItem.titleView = imageView;
viewController.navigationItem.titleView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yourimage.png"]];
我遇到了同样的问题,因为iOS 11和Xcode 9开始使用自动布局而不是帧来管理导航栏,你应该知道你的导航栏布局。
在WWDC Session 204中,为iOS 11更新应用程序时声明UIToolBar和UINavigationBar已升级为使用自动布局,为了避免零大小的自定义视图,您应该了解一些相关信息。
UINavigation和UIToolBar提供位置,不关心它。
您必须使用以下之一提供自定义视图的大小:
回答你的问题,我用一个ImageView设置titleView,以两种不同的方式提供大小:
明确给出高度和宽度。
-(void)updateNavTitleView{
UIImageView *imageView = [[UIImageView alloc] initWithImage:[ UIImage imageNamed:@"TitleViewImage"]];
[imageView.widthAnchor constraintEqualToConstant:160].active = YES;
[imageView.heightAnchor constraintEqualToConstant:44].active = YES;
self.navigationItem.titleView = imageView;
}
或者将纵横模式设置为aspectFit
-(void) updateNavTitleView{
UIImageView *imageView = [[UIImageView alloc] initWithImage:[ UIImage imageNamed:@"TitleViewImage"]];
[imageView setContentMode:UIViewContentModeScaleAspectFit];
self.navigationItem.titleView = imageView;
}
如果你想观看Session,Session 204
试试这个 :
UIImage *logo = [UIImage imageNamed:@"logo.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage: logo];
imageView.frame = CGRectMake(160, 2, 40, 40);
self.navigationItem.titleView = [[UIImageView alloc] initWithImage:logo];
UIImageView *navbarImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"logo.png"]];
navbarImageView.contentMode = UIViewContentModeScaleAspectFit;
self.navigationBar.titleView = navbarImageView;
如果有人需要在Swift(4.2)中执行上述操作:
记下以下功能:
func addMiddleImage(){
//Initialize your UIImage
let yourImage = UIImage(named: "imageName")!.withRenderingMode(.alwaysOriginal)
//Initialize a UIImageView
let imageView = UIImageView(image: yourImage)
//Set your Navigation Bar to the inialized UIImageView
self.navigationItem.titleView = imageView
}
将它添加到您的ViewDidLoad()回调:
override func viewDidLoad() {
super.viewDidLoad()
self.addMiddleImage()
}
祝好运