在iOS上,是否有可能使一个视图始终浮动在所有其他视图之上。我之所以问这个问题,是因为我想实现的是一个视图浮动在ViewController之上,然后一个Modal View Controller滑入,而该特定视图仍浮动在该Modal View Controller之上(希望你明白我的意思)。
有的。当需要时,您可以将您的视图添加到主要的window
并将其置于前台。
在下面的代码中,假设_viewConroller
和_anotherView
是appDelegate的强属性 - 当然,配置可能不同。
以下代码将在屏幕左上角添加一个小蓝色正方形。
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
_viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
_anotherView = [[UIView alloc] initWithFrame: CGRectMake (0.0,0.0,20.0,20.0)];
[anotherView setBackgroundColor: [UIColor blueColor]];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
[self.window addSubView: _anotherView];
[self.window bringSubViewToFront: _anotherView]; //not really needed here but it doesn't do any harm
return YES;
}
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
UIViewController *_vc = [sb instantiateViewControllerWithIdentifier:@"FloatingController"];
_anotherView = _vc.view;
[_anotherView setTranslatesAutoresizingMaskIntoConstraints:NO];
[self.window addSubview: _anotherView];
[[VLBConstraintsGenerator sharedInstance] setWidth:200 forView:_anotherView inSuperView:_window];
[[VLBConstraintsGenerator sharedInstance] setHeight:200 forView:_anotherView inSuperView:_window];
[[VLBConstraintsGenerator sharedInstance] setLeading:0 forView:_anotherView inSuperView:_window];
[_anotherView setBackgroundColor:[UIColor grayColor]];
[[_anotherView layer] setBorderWidth:1];
[[_anotherView layer] setBorderColor:[UIColor yellowColor].CGColor];
[self.window makeKeyAndVisible];
[self.window bringSubviewToFront:_anotherView]; //not really needed here but it doesn't do any harm
您需要做的是将一个视图控制器拖入您的主故事板,并将其设为FloatingController作为故事板ID。
附加方法
-(void)setWidth:(CGFloat )theWidth forView:(UIView *)theView inSuperView:(UIView *)theSuperView
{
assert([theSuperView isEqual:theView.superview]);
NSLayoutConstraint *cn = [NSLayoutConstraint constraintWithItem:theView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1
constant:theWidth];
// [cn setPriority:999];//make it variable according to the orientation
[theSuperView addConstraint:cn];
}
-(void)setHeight:(CGFloat )theHeight forView:(UIView *)theView inSuperView:(UIView *)theSuperView
{
assert([theSuperView isEqual:theView.superview]);
NSLayoutConstraint *cn = [NSLayoutConstraint constraintWithItem:theView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1
constant:theHeight];
[theSuperView addConstraint:cn];
}
-(void)setLeading:(CGFloat )theLeading forView:(UIView *)theView inSuperView:(UIView *)theSuperView
{
assert([theSuperView isEqual:theView.superview]);
NSLayoutConstraint *cn = [NSLayoutConstraint constraintWithItem:theView
attribute:NSLayoutAttributeLeading
relatedBy:NSLayoutRelationEqual
toItem:theSuperView
attribute:NSLayoutAttributeLeading
multiplier:1
constant:theLeading];
[theSuperView addConstraint:cn];
}
private var bannerLabel: UILabel = UILabel()
private let view = UIView()
// label background color
let greenColor = UIColorFromRGB(63,g: 161,b: 81)
let warningColor = UIColorFromRGB(252,g: 140,b: 38)
let errorColor = UIColorFromRGB(252,g: 66,b: 54)
func showBannerWithOption(title: String, color: UIColor) {
view.frame = CGRect(x: 50, y: 150, width: 200, height: 45)
let window = UIApplication.shared.keyWindow
guard let mainWindow = window else { return }
mainWindow.addSubview(view)
view.centerXAnchor.constraint(equalTo: mainWindow.centerXAnchor).isActive = true
view.centerYAnchor.constraint(equalTo: mainWindow.centerYAnchor).isActive = true
bannerLabel.frame = CGRect(x: 50, y: 150, width: 200, height: 21)
bannerLabel.backgroundColor = color
bannerLabel.textColor = UIColor.black
bannerLabel.textAlignment = .center
bannerLabel.text = title
view.addSubview(bannerLabel)
bannerLabel.translatesAutoresizingMaskIntoConstraints = false
bannerLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
bannerLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = true
bannerLabel.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
bannerLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
}
首先,我添加一个视图并设置一些CGRect,然后我设置了一个窗口(主窗口),在里面添加了一个创建的视图。
之后,我设置了一个标签,并设置了与视图相等的约束。
如果您需要在多个地方使用标题和颜色显示横幅,可以使用以下函数:function showBannerWithOption。
如果您想调用此函数,只需执行以下操作:
override func viewDidLoad() {
super.viewDidLoad()
showBannerWithOption(title: "test", color: greenColor)
}
这就是全部内容 :) 这是Swift 5.0
现在你可以根据自己的需要进行定制。