Question

在iOS上是否可以将视图始终浮动在所有其他视图之上。我问这个是因为我想要实现的是一个浮动在ViewController上方的视图，然后一个模态视图控制器滑入，同时该特定视图仍然漂浮在该模态视图控制器上（希望你得到我想说的话））。

Answer 1

有。您可以将视图添加到主window并在必要时将其显示在前面。

在下面的代码中假定_viewConroller和_anotherView是appDelegate的强大属性 - 配置当然可能不同。

此代码会在屏幕左上角添加小蓝色方块。

- (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;
}

Answer 2

如果您使用的是storyboard和autolayout（受到第一个答案的启发），您可以执行以下操作

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

您需要做的就是将视图控制器拖动到主故事板中，将 FloatingController 作为故事板ID

其他方法

-(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];
}

Answer 3

我对这个问题的解决方案是这样的。我将创建UIView，内部将是UILabel。

首先在某个类中进行设置：

 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)

在那之后，您添加类似这样的内容。

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
    }

仅说明一下，首先，我添加了一个视图并设置了一些CGRect，然后设置了一个窗口（主窗口）。在其中，我添加了一个已创建的视图。

在那之后，我设置了一个标签，并将约束设置为与视图相等。

如果需要在一个以上的地方使用

具有标题和颜色的showBannerWithOption函数，就像这样。

如果要调用此功能只需执行以下操作：

    override func viewDidLoad() {
        super.viewDidLoad()
    showBannerWithOption(title: "test", color: greenColor) 
}

仅此而已:) 这是迅速的5.0

现在，您可以根据需要进行自定义。

查看浮动在所有ViewControllers上方

3 个答案: