Putting a UIView or UIWindow above Statusbar

问题

My goal is to draw an invisible button above the status bar on the top of my iPhone app (dimension 320*20 pixels).

No matter what I try, something is buggy:

1. For example, I tried to create a new view. When I want to place the view on the top of my app, it always disappears behind the status bar instead of being in front of it!

2. I found another great idea on Stackoverflow: Add UIView Above All Other Views, Including StatusBar Even if a second UIWindow isn't recommended, I tried to implement it. It worked as I wanted until the moment that I noticed a problem: the keyboard doesn't appear anymore when needed (for example when clicking in a textbox)!

How can I possibly fix this? Or is there a better approach to my problem? This is my code for creating the second window:

// Create window
statusWindow = [[UIWindow alloc] initWithFrame:CGRectMake(0,0,320,20)];
statusWindow.windowLevel = UIWindowLevelStatusBar;
[statusWindow makeKeyAndVisible];

// Create statusBarButton
statusBarButton = [UIButton buttonWithType:UIButtonTypeCustom];
CGRect buttonFrame2 = statusBarButton.frame;
buttonFrame2.size = CGSizeMake(320,20);
statusBarButton.frame = buttonFrame2;
[statusBarButton addTarget:self action:@selector(goTop) forControlEvents:UIControlEventTouchUpInside]; 

// Place button into the new window
[statusWindow addSubview:statusBarButton];

回答1:

In the documentation for -[UIWindow makeKeyAndVisible]:

This is a convenience method to make the receiver the main window and displays it in front of other windows. You can also hide and reveal a window using the inherited hidden property of UIView.

The "key window" is the one that gets certain input events; text fields in a non-key window might not work. There are two things you can do:

• Call [window makeKeyAndVisible] on the old key window afterwards
• Set statusWindow.hidden = NO instead (but I don't see why it would be hidden by default). I don't think you can "display it in front of other windows" like -makeKeyAndVisible does; windows don't have a superview you can call -bringSubviewToFront: on IIRC.

回答2:

in AppDelegate file

self.window.windowLevel = UIWindowLevelStatusBar;

or in any other class

[AppDelegate appDelegate].window.windowLevel = UIWindowLevelStatusBar;

and if you want to make status bar to be on the top again u can set

self.window.windowLevel = UIWindowLevelNormal;

回答3:

If other users want to implement this, here my solution:

// Create window
statusWindow = [[UIWindow alloc] initWithFrame:CGRectMake(0,0,320,20)];
statusWindow.windowLevel = UIWindowLevelStatusBar;
// Dont make the statusWindow keyWindow or the keyboard won't work!
// [statusWindow makeKeyAndVisible];

// Create statusBarButton
statusBarButton = [UIButton buttonWithType:UIButtonTypeCustom];
CGRect buttonFrame2 = statusBarButton.frame;
buttonFrame2.size = CGSizeMake(320,20);
statusBarButton.frame = buttonFrame2;
[statusBarButton addTarget:self action:@selector(goTop) forControlEvents:UIControlEventTouchUpInside]; 

// Place button into the new window
[statusWindow addSubview:statusBarButton];

// Instead, add this:
[window makeKeyAndVisible]; // has to be main window of app
statusWindow.hidden = NO; // without this the statusWindow won't appear

回答4:

Try:

[self.view bringSubviewToFront:statusWindow];

I dont think its possible to bring a view in front of the status bar though.

来源：https://stackoverflow.com/questions/4252053/putting-a-uiview-or-uiwindow-above-statusbar