如何从 UITabBarButton 检索 CGRect 框架？

Question

我的目标是在我的教程中启动应用程序时为我的每个 UITabBarbuttons 显示一个 UIPopover...我正在执行以下操作：

如何从UIView *tabView = [[appDelegate tabBarMutableArray] objectAtIndex:1]; 中提取框架，这是第一个 UITabBarButton。

Array AppDelegate: <UITabBarButton: 0x145d06a70; frame = (254 1; 76 55); opaque = NO; layer = <CALayer: 0x17802c160>>

现在我手动输入 254,712,76,55 的 GCRect。我通过减去 768 - 56 得到 712，并且弹出框处于完美位置。但我宁愿通过检索值来进行计算...那么如何提取上述结果的frame = (254 1; 76 55) 部分？

frame = CGRectMake(254,712,76,55);

AppDelegate.h

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

- (NSMutableArray *)tabBarMutableArray;

@end

AppDelegate.m

#import "AppDelegate.h"

@implementation AppDelegate
#define debug 1

- (NSMutableArray *)tabBarMutableArray;
{
    if (debug==1) {
        NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));
    }

    UITabBarController *tabController           = (UITabBarController *)self.window.rootViewController;
    NSMutableArray     *tabBarItemsMutableArray = [NSMutableArray new];

    UITabBar *tabBar = tabController.tabBar;

    for (UIView *view in tabBar.subviews)
    {
        [tabBarItemsMutableArray addObject:view.description];
    }

    return  tabBarItemsMutableArray;
}

viewcontroller.m

-(void)showHomeTabBarPopOver
{
    if (debug==1) {
        NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));
    }

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    CGRect frame    = CGRectZero;

    NSLog(@"%@", [appDelegate tabBarMutableArray]);

    NSLog(@"Array AppDelegate: %@", [[appDelegate tabBarMutableArray] objectAtIndex:1]);


    UIView *tabView = [[appDelegate tabBarMutableArray] objectAtIndex:1];
    NSLog(@"tabView %@", [tabView valueForKey:@"frame"]);

    //    frame           = tabView.frame;
    NSLog(@"frame %@", CGRectCreateDictionaryRepresentation(self.view.frame));

    frame = CGRectMake(254,712,76,55); //254,712,76,55

    [_getStartedPopover presentPopoverFromRect:frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];

}

结果

2014-02-07 14:35:47.940 mCC HD[1964:60b] (
    "<_UITabBarBackgroundView: 0x145d0cb30; frame = (0 0; 1024 56); autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0x17802db00>>",
    "<UITabBarButton: 0x145d06a70; frame = (254 1; 76 55); opaque = NO; layer = <CALayer: 0x17802c160>>",
    "<UITabBarButton: 0x145e2e360; frame = (364 1; 76 55); opaque = NO; layer = <CALayer: 0x17003c2e0>>",
    "<UITabBarButton: 0x145d0a060; frame = (474 1; 76 55); opaque = NO; layer = <CALayer: 0x17802c6a0>>",
    "<UITabBarButton: 0x145d0a640; frame = (584 1; 76 55); opaque = NO; layer = <CALayer: 0x17802ca20>>",
    "<UITabBarButton: 0x145d0ae60; frame = (694 1; 76 55); opaque = NO; layer = <CALayer: 0x17802cda0>>",
    "<UIImageView: 0x145d0edd0; frame = (0 -0.5; 1024 0.5); autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0x17802f0a0>>"
)
2014-02-07 14:35:47.940 mCC HD[1964:60b] Running AppDelegate 'tabBarMutableArray'
2014-02-07 14:35:47.941 mCC HD[1964:60b] Array AppDelegate: <UITabBarButton: 0x145d06a70; frame = (254 1; 76 55); opaque = NO; layer = <CALayer: 0x17802c160>>
2014-02-07 14:35:47.943 mCC HD[1964:60b] frame {
    Height = 768;
    Width = 1024;
    X = 0;
    Y = 0;

提前谢谢...

-保罗斯

Answer 1

编辑：

（抱歉，在我的第一个答案中，我没有查看 tabBarMutableArray 是如何创建的。）

---

在您的 AppDelegate 中，tabBarItemsMutableArray（这是您的 -tabBarMutableArray 方法的返回值）是这样创建的：

for (UIView *view in tabBar.subviews)
{
    [tabBarItemsMutableArray addObject:view.description];
}

因此，该数组中不包含 UIView 对象，而是包含 NSString 对象（所有子视图的描述）。这就是为什么 viewcontroller.m 中的以下行不正确并且无法按预期工作的原因：

    UIView *tabView = [[appDelegate tabBarMutableArray] objectAtIndex:1];

该行的右侧是NSString，左侧是UIView。

---

您可以通过添加行来解决此问题

AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];        
UITabBarController *tabController = (UITabBarController *)appDelegate.window.rootViewController;
UITabBar *tabBar = tabController.tabBar;
UIView *tabView = [tabBar.subviews objectAtIndex:1];
CGRect frame = tabView.frame

到您的-showHomeTabBarPopOver 方法。 （虽然有更简洁的方法取决于你想做什么......）

---

如果您需要所有标签栏项目的框架，而不仅仅是“索引：1”这个特定的项目，我建议您在 AppDelegate.h 中创建一个属性：

@property (strong, nonatomic) NSArray *tabBarViews;

并在您的 AppDelegate.m 中实现其 getter 方法：

- (NSArray *)tabBarViews {
    UITabBarController *tabController  = (UITabBarController *)self.window.rootViewController;
    UITabBar *tabBar = tabController.tabBar;

    return tabBar.subviews;
}

然后，您可以从 viewcontroller.m 中更轻松地访问您的标签栏视图，包括它们的框架：

AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate]; 

UIView *tabView0 = [appDelegate.tabBarViews objectAtIndex:0];
CGRect frame0 = tabView0.frame;

UIView *tabView1 = [appDelegate.tabBarViews objectAtIndex:1];
CGRect frame1 = tabView1.frame;

等等