这篇文章,我将分享对UIWindow我所知道的东西。

keyWindow

一个应用能够有许多UIWindow,“The key window”是其中一个,被设计用来接受键盘和其他与点击无关的事件。一个时间段中,如果只有一个Window,那么他就可能是keyWindow。

调用makeKeyAndVisible或者makeKeyWindow,能够使一个UIWindow变成keyWindow。注意,默认情况下,UIWindow是隐藏的。所以调用makeKeyAndVisible,即使一个UIWindow变成了keyWindow,又把它的hidden属性设为NO。

UIWindow is always portrait

在application:didFinishLaunchingWithOptions:中增加以下代码:

 UIView *view = [[UIView alloc] initWithFrame:CGRectMake(, , , )];
view.backgroundColor = [UIColor greenColor];
view.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleBottomMargin;
[self.window addSubview:view];
view.layer.zPosition = FLT_MAX;

接着,旋转模拟器或者设备,你将会看到绿色视图总在坐标点{0, 0}。

UIWindow’s的坐标系统总是在竖直方向,旋转是通过设置根控制器的位移。所以,自从iOS4开始,应用建议有根控制器。

Keyboard is a window

注意,UIApplication有一个“windows”的实例化方法。

The app’s visible and hidden windows. (read-only)
This property contains the UIWindow objects currently associated with the app. This list does not include windows created and managed by the system, such as the window used to display the status bar.

你能够获取keyboardwindow通过遍历windows array。摘录于SVProgressHUD中得代码。注意,当keyboard显示出来时,window array中包含一种UITextEffectsWindow类型的window。

 - (CGFloat)visibleKeyboardHeight {

     UIWindow *keyboardWindow = nil;
for (UIWindow *testWindow in [[UIApplication sharedApplication] windows]) {
if(![[testWindow class] isEqual:[UIWindow class]]) {
keyboardWindow = testWindow;
break;
}
} for (__strong UIView *possibleKeyboard in [keyboardWindow subviews]) {
if([possibleKeyboard isKindOfClass:NSClassFromString(@"UIPeripheralHostView")] || [possibleKeyboard isKindOfClass:NSClassFromString(@"UIKeyboard")])
return possibleKeyboard.bounds.size.height;
} return ;
}

之前说过,UIWindow的坐标系统总是横屏的,Keyboard也是一个window,所以不管设备是的怎么样的方向,他的frame总是 (0 0; 320 480)。当你旋转设备时,系统发送一个旋转位移消息给keyboard window。

设备旋转到竖屏:

<UITextEffectsWindow: 0x8e3ecc0; frame = ( ;  ); opaque = NO; gestureRecognizers = <NSArray: 0x8e3f240>; layer = <UIWindowLayer: 0x8e3ee40>>

设备旋转到横屏:

<UITextEffectsWindow: 0x8e3ecc0; frame = ( ;  ); transform = [, , -, , -, ]; opaque = NO; gestureRecognizers = <NSArray: 0x8e3f240>; layer = <UIWindowLayer: 0x8e3ee40>>
Notification

如果你注册了UIKeyboardWillShowNotification,你能够确认的是:

 [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillShowNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
NSLog(@"%@", note);
}];

设备旋转到竖屏:

UIKeyboardFrameEndUserInfoKey = “NSRect: {{0, 264}, {320, 216}}”;

设备旋转到横屏:

UIKeyboardFrameEndUserInfoKey = “NSRect: {{0, 0}, {162, 480}}”;

所以,在你UIKeyboardWillShowNotification接受后,你应该把他转变成你View的坐标系统。代码摘录于Keyboard “WillShow” and “WillHide” vs. Rotation

 - (void) keyboardWillShow:(NSNotification *)aNotification
{
CGRect keyboardFrame = [[[aNotification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
CGRect convertedFrame = [self.view convertRect:keyboardFrame fromView:self.view.window]; ......
/* Do whatever you want now with the new frame.
* The width and height will actually be correct now
*/
......
}

Statusbar is a window

之前说过,windows array不包含the statusbar window,the statusbar window是UIStatusBarWindow类型的,你能够通过以下代码获取。

- (UIWindow *)statusWindow
{
NSString *statusBarString = [NSString stringWithFormat:@"_statusBarWindow"];
return [[UIApplication sharedApplication] valueForKey:statusBarString];
}

就像 the keyboard window, the status bar的大小不会改变,当你旋转屏幕,系统会将旋转消息发送给状态栏。

设备旋转到竖屏:

 <UIStatusBarWindow: 0x8f61e30; frame = ( ;  ); gestureRecognizers = <NSArray: 0x8f62e40>; layer = <UIWindowLayer: 0x8f620d0>>

设备旋转到横屏:

 <UIStatusBarWindow: 0x8f61e30; frame = ( ;  ); transform = [, , -, , , ]; gestureRecognizers = <NSArray: 0x8f62e40>; layer = <UIWindowLayer: 0x8f620d0>>
statusBarFrame

UIApplication有一个属性,叫statusBarFrame,是在竖屏坐标系统下的。

 CGRect rect = [UIApplication sharedApplication].statusBarFrame;
NSLog(@"statusBarFrame %@", NSStringFromCGRect(rect));

设备旋转到竖屏:

statusBarFrame {{0, 0}, {320, 20}}

设备旋转到横屏:

statusBarFrame {{300, 0}, {20, 480}}

如果你仅仅想获取状态栏高度,而不管设备方向,你能通过以下方式获取:

float statusBarHeight = MIN([UIApplication sharedApplication].statusBarFrame.size.height, [UIApplication sharedApplication].statusBarFrame.size.width);
Notification

当设备旋转,系统发送通知UIApplicationWillChangeStatusBarFrameNotification和UIApplicationDidChangeStatusBarFrameNotification。
让我们来看,接受UIApplicationDidChangeStatusBarFrameNotification后处理。

 [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationWillChangeStatusBarFrameNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
NSLog(@"%@", note);
}]; [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationDidChangeStatusBarFrameNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
NSLog(@"%@", note);
}];

How to create alert view

有两种方式创建alertView.

Don’t use rootViewController approach

像OLGhostAlertView,SVProgressHUD,WYPopoverController,MTStatusBarOverlay,这样的第三方库,不使用rootViewController。他们创建新window(MTStatusBarOverlay)或者使用存在的UIWindow,他们直接在window上添加子视图。所以他们通过接受UIApplicationDidChangeStatusBarOrientationNotification和UIApplicationWillChangeStatusBarFrameNotification来处理视图方向的。

处理大妈如下,摘录于SVProgressHUD。方法是手动获取屏幕方向并且发送一个 rotation transform 给他的视图。

 - (void)handleOrientationChange:(NSNotification *)note
{
UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation]; CGRect orientationFrame = [UIScreen mainScreen].bounds;
CGRect statusBarFrame = [UIApplication sharedApplication].statusBarFrame; if(UIInterfaceOrientationIsLandscape(orientation)) {
float temp = orientationFrame.size.width;
orientationFrame.size.width = orientationFrame.size.height;
orientationFrame.size.height = temp; temp = statusBarFrame.size.width;
statusBarFrame.size.width = statusBarFrame.size.height;
statusBarFrame.size.height = temp;
} switch (orientation) {
case UIInterfaceOrientationPortraitUpsideDown:
rotateAngle = M_PI; break;
case UIInterfaceOrientationLandscapeLeft:
rotateAngle = -M_PI/2.0f; break;
case UIInterfaceOrientationLandscapeRight:
rotateAngle = M_PI/2.0f; break;
default: // as UIInterfaceOrientationPortrait
rotateAngle = 0.0; break;
} }
How to add view to existing window

第三方库都有他们的在windows上添加视图的方法。

SVProgressHUD 是在最前面的window上添加视图的。

 if(!self.overlayView.superview){
NSEnumerator *frontToBackWindows = [[[UIApplication sharedApplication]windows]reverseObjectEnumerator]; for (UIWindow *window in frontToBackWindows)
if (window.windowLevel == UIWindowLevelNormal) {
[window addSubview:self.overlayView];
break;
}
}
How the OS creates AlertView

在WWDC 2014 Session 228,“A Look Inside Presentation Controllers”,他们说:

Behind the scenes, the framework creates a window on your app’s behalf, but this predates iOS  window rotation behavior, so this window is technically still in portrait.

We then add the action sheet to that window and mimic the transform hierarchy of the presenting view to get into the right orientation.

Use rootViewController approach

一些第三方库,像FLEX,SIAlertView...他们创建一个新window,并且将根控制器赋予给window。这种方式下,设备方向旋转发送给了rootViewController,他们在根控制器上添加视图。添加视图和控制设备方向的代码都在控制器中。

代码摘抄于FLEXViewExplorerViewController:

 - (NSUInteger)supportedInterfaceOrientations
{
UIViewController *viewControllerToAsk = [self viewControllerForStatusBarAndOrientationProperties];
NSUInteger supportedOrientations = [FLEXUtility infoPlistSupportedInterfaceOrientationsMask];
if (viewControllerToAsk && viewControllerToAsk != self) {
supportedOrientations = [viewControllerToAsk supportedInterfaceOrientations];
} // The UIViewController docs state that this method must not return zero.
// If we weren't able to get a valid value for the supported interface orientations, default to all supported.
if (supportedOrientations == ) {
supportedOrientations = UIInterfaceOrientationMaskAll;
} return supportedOrientations;
} - (BOOL)shouldAutorotate
{
UIViewController *viewControllerToAsk = [self viewControllerForStatusBarAndOrientationProperties];
BOOL shouldAutorotate = YES;
if (viewControllerToAsk && viewControllerToAsk != self) {
shouldAutorotate = [viewControllerToAsk shouldAutorotate];
}
return shouldAutorotate;
} - (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
[...]
} - (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
[...]
}

因为FLEX创建了新Window,Window必须询问app原始的Window才能获取旋转消息。注意infoPlistSupportedInterfaceOrientationsMask和viewControllerForStatusBarAndOrientationProperties两个属性。你能够从中学到很多。

UIWindow is a UIView

因为UIWindow是UIView的子类,你能够想UIView一样对UIWindow做很多事情。

例如,FLEX重写了pointInside:withEvent: to,用来拦截它的toolbar上的点击。

 - (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{
BOOL pointInside = NO;
if ([self.eventDelegate shouldHandleTouchAtPoint:point]) {
pointInside = [super pointInside:point withEvent:event];
}
return pointInside;
}

UIWindow in iOS 8

在iOS8,苹果引入了Size Classes,并且“旋转是一种动画式的视图边界变化”。并且UIWindow能够获取屏幕旋转通知。

在WWDC 2014 Session 216,《Building Adaptive Apps with UIKit》

Trait Environments are a new protocol that are able to return their current Trait Collection, and these include Screens, Windows, View Controllers, and also Views.

All of these are able to return their current Trait Collection to you to use to determine how your interface should be laid out.

UIWindow in iOS的更多相关文章

  1. [iOS基础控件 - 6.10.7] UIWindow

    A.UIWindow概念 1.继承UIView,是一种特殊的UIView 2.通常一个APP只有一个UIWindow 3.iOS程序启动后,创建的第一个视图就是UIWindow 4.没有UIWindo ...

  2. iOS开发之UIWindow

    1.概述 UIWindow是一种特殊的UIView,通常在一个app中只会有一个UIWindow. iOS程序启动完毕后,创建的第一个视图控件就是UIWindow,接着创建控制器的view,最后将控制 ...

  3. iOS.UI.UIWindow

    UIWindow 1. UIWindow 2. UIWindow的使用场景 2.1 额外添加的Window需要手动进行旋转 最近有遇到一个UIWindow的使用场景:在ApplicationDeleg ...

  4. AJ学IOS(22)UI之UIApplicationDelegate和UIWindow

    AJ分享,必须精品 UIApplicationDelegate 每次新建完项目,都有个带有“AppDelegate”字眼的类,它就是UIApplication的代理 NYAppDelegate默认已经 ...

  5. 你真的了解UIWindow吗?

    一:首先查看一下关于UIWindow的定义 NS_CLASS_AVAILABLE_IOS(2_0) @interface UIWindow : UIView //window的屏幕,默认是 [UISc ...

  6. 关于UIWindow(转)

    (原文出自:http://www.cnblogs.com/wendingding/p/3770052.html,特别感谢) 一:[[UIScreen mainScreen] bounds] 和[UIS ...

  7. iOS开发之App启动原理

    iOS程序的启动过程 程序启动的完整过程大致步骤如下: 1.main函数 2.UIApplicationMain * 创建UIApplication对象 * 创建UIApplication的deleg ...

  8. iOS UIKit:view

    @import url(http://i.cnblogs.com/Load.ashx?type=style&file=SyntaxHighlighter.css); @import url(/ ...

  9. iOS Multiview Applications

    @import url(http://i.cnblogs.com/Load.ashx?type=style&file=SyntaxHighlighter.css); @import url(/ ...

随机推荐

  1. Velocity 语法示例

    一.简介: 1)它允许任何人使用简单而强大的模板语言来引用定义在 java 代码中的对象" 2)Velocity是一个基于java的模板引擎,简称VTL(Velocity Template ...

  2. Linux学习一些在Terminal可以用到的快捷键及Shell常用的通配符

    Ctrl+c 终断程序 Ctrl+d 键盘输入结束或退出终端 Ctrl+s 暂定当前程序,暂停后按下任意键恢复运行 Ctrl+z 将当前程序放到后台运行,恢复到前台为命令fg Ctrl+a 将光标移至 ...

  3. css中常用的标签

    最常用的标签 left 左 top 上 right 右 bottom 下 font 字体 size 大小 width 宽度 height 高度 class 类 label 标签 form 表单 gro ...

  4. DDD(Domain Driver Designer) 领域驱动设计简介

    领域驱动设计之领域模型 加一个导航,关于如何设计聚合的详细思考,见这篇文章. 2004年Eric Evans 发表Domain-Driven Design –Tackling Complexity i ...

  5. IPointCollection,ISegmentCollection和IGeometryCollection

    Engine 提供了三个主要的几何图形集合接口用于对几何对象的操作,分别是 IPointCollection,ISegmentCollection 和 IGeometryCollection,这些接口 ...

  6. scala学习笔记——操作符

    中置操作符(二元操作符),操作符位于两个参数之间.操作符包括字母,比如to,也可以包括操作符字符,比如1->10,等同于方法调用1.->(10) a 标识符 b 其中的标识符是一个带有两个 ...

  7. jquery1.9学习笔记 之选择器(基本元素四)

    ID选择器("#id") 描述: 选择与给出ID属性匹配的单元标签. 对于ID选择器,jquery使用JS的函数document.getElementById(),当一个标签附加到 ...

  8. C程序设计语言练习题1-5

    练习1-5 修改温度转换程序,要求以逆序(即按照从300度到0度的顺序)打印温度转换表. 代码如下: #include <stdio.h> // 包含标准库的信息. int main() ...

  9. C语言结构体(struct)常见使用方法

    基本定义:结构体,通俗讲就像是打包封装,把一些变量有共同特征(比如同属于某一类事物的属性)的变量封装在内部,通过一定方法访问修改内部变量. 结构体定义: 第一种:只有结构体定义 struct stuf ...

  10. 树莓派设置固定ip

    2016发布的rasbian采用的网络机制是dhcpcd: 不能使用以前的修改配置文件/etc/network/interfaces: 新的配置方式保持/etc/network/interfaces不 ...