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keyWindow与delegate中Window的区别

2024-07-29 04:34:52   222人阅读

keyWindow与delegate中Window的区别

源码：

////  ViewController.m//  UIWindowRelated////  Created by YouXianMing on 14/10/25.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    NSLog(@"-------");    NSLog(@"%@", [UIApplication sharedApplication].keyWindow);    NSLog(@"%@", [[[UIApplication sharedApplication] delegate] window]);}- (void)viewDidAppear:(BOOL)animated {    NSLog(@"#######");    NSLog(@"%@", [UIApplication sharedApplication].keyWindow);    NSLog(@"%@", [[[UIApplication sharedApplication] delegate] window]);}@end

结果如下图：

从打印结果中可以知道：

keyWindow与delegate中的window其实是一样的，keyWindow的存在的意义，其实就是为了说明当前的window接管了这个控制器的view而已，你可以在keyWindow上加载你自己的建立的view了。

现在提供一个便利的类目^_^:

////  UIWindow+Window.h//  Window////  Created by YouXianMing on 14-10-10.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import <UIKit/UIKit.h>@interface UIWindow (Window)/** *  返回keyWindow（如果keyWindow有值，代表着你可以给window添加view了） * *  @return 可以添加view并显示出来的window（如果返回为nil，说明你不能将view添加到window上去显示） */+ (UIWindow *)usableWindow;/** *  返回window * *  @return window（你给这个window添加的view很有可能被控制器的view覆盖而显示不了） */+ (UIWindow *)rootWindow;@end
////  UIWindow+Window.m//  Window////  Created by YouXianMing on 14-10-10.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import "UIWindow+Window.h"@implementation UIWindow (Window)+ (UIWindow *)usableWindow{    return [UIApplication sharedApplication].keyWindow;}+ (UIWindow *)rootWindow{    return [[[UIApplication sharedApplication] delegate] window];}@end

 

keyWindow与delegate中Window的区别


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