为什么self.view.subviews在viewDidLoad中是一个空数组？ [英] Why is self.view.subviews an empty array in viewDidLoad?

问题描述

我使用Interface Builder创建了一堆UI元素，并使用IBOutlets将它们连接到我的ViewController。

I've created a bunch of UI elements using Interface Builder and hooked them up to my ViewController using IBOutlets.

然而，当我尝试迭代 self.view.subviews 在我的ViewController的 viewDidLoad 方法中，我发现子视图数组为空。

However, when I try to iterate through self.view.subviews in my ViewController's viewDidLoad method, I find that the subviews array is empty.

• ViewController.xib ：

UIView
|
- UILabel
- UIButton
- // ... more stuff
- UIToolbar

ViewController.m ：

#import "ViewController.h"
@interface ViewController ()
// Interface elements
@property IBOutlet UILabel *titleLabel;
@property IBOutlet UIButton *button1;
// ... etc
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // BREAK_POINT

    // ... code to wire up the UIButtons to dynamically created objects
}

调试器输出 BREAK_POINT ：

(lldb) po self.view
<UIView: 0x7fa7897e2140; frame = (0 0; 600 600); autoresize = W+H; layer = <CALayer: 0x7fa7897e2210>>

(lldb) po self.view.subviews
<__NSArrayI 0x7fa789713500>(

)
(lldb) po [self.view.subviews count];
 nil
(lldb) po self.button1
<UIButton: 0x7fa78955ea70; frame = (-23 -15; 46 30); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0x7fa7897663d0>>

为什么self.views.subviews是的任何想法当UIButtons等已经初始化并正确连接到IBOutlets时为空？

Any ideas why self.views.subviews is empty when clearly the UIButtons, etc have been initialized and wired up to the IBOutlets correctly?

编辑1：我重命名为 MainView.xibtoViewController.xib并删除了我的 ViewController.m 中的 loadView 实现，而我'我仍然看到相同的 self.view.subviews 行为。

Edit 1: I renamed "MainView.xib" to "ViewController.xib" and removed the loadView implementation in my ViewController.m, and I'm still seeing the same self.view.subviews behavior.

推荐答案

尝试这样做

- (void)viewDidLayoutSubviews{


}

加载所有子视图后调用此方法。希望这会对你有所帮助：）

This method get called after loading all the subviews. Hope this will help you :)

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