UIBarButtonItem：如何找到其框架？

我在工具栏中有一个按钮。我如何抓住它的框架？做UIBarButtonItem不是有一个frame属性？

试试这个；

UIBarButtonItem *item = ... ;
UIView *view = [item valueForKey:@"view"];
CGFloat width;
if(view){
    width=[view frame].size.width;
}
else{
    width=(CGFloat)0.0 ;
}

这种方式最适合我：

UIView *targetView = (UIView *)[yourBarButton performSelector:@selector(view)];
CGRect rect = targetView.frame;

感谢Anoop Vaidya的建议答案。一种替代方法是（假设您知道按钮在工具栏中的位置）

UIView *view= (UIView *)[self.toolbar.subviews objectAtIndex:0]; // 0 for the first item


CGRect viewframe = view.frame;

使用Swift时，如果需要经常使用条形按钮项目，则应实现如下扩展：

extension UIBarButtonItem {

    var frame: CGRect? {
        guard let view = self.value(forKey: "view") as? UIView else {
            return nil
        }
        return view.frame
    }

}

然后，您可以在代码中轻松访问：

if let frame = self.navigationItem.rightBarButtonItems?.first?.frame {
    // do whatever with frame            
}

哎呀，这个线程有很多粗略的答案。这是正确的方法：

import UIKit

class ViewController: UIViewController {

    let customButton = UIButton(type: .system)

    override func viewDidLoad() {
        super.viewDidLoad()

        customButton.setImage(UIImage(named: "myImage"), for: .normal)
        self.navigationItem.rightBarButtonItem = UIBarButtonItem(customView: customButton)
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        print(self.customButton.convert(self.customButton.frame, to: nil))
    }
}

这是我在iOS 11和Swift 4中使用的内容。如果没有可选的选项，可能会更干净一些，但我正在安全地使用它：

extension UIBarButtonItem {
    var view: UIView? {
        return perform(#selector(getter: UIViewController.view)).takeRetainedValue() as? UIView
    }
}

和用法：

if let barButtonFrame = myBarButtonItem.view?.frame {
    // etc...
}

-(CGRect) getBarItemRc :(UIBarButtonItem *)item{
    UIView *view = [item valueForKey:@"view"];
    return [view frame];
}

您可以通过使用navigationBar之类的属性layoutMargins和frame与《人机界面指南》中的图标尺寸指南相结合来大致计算它，并考虑当前设备的方向：

- (CGRect)rightBarButtonFrame {
    CGFloat imageWidth = 28.0;
    CGFloat imageHeight = UIDevice.currentDevice.orientation == UIDeviceOrientationLandscapeLeft || UIDevice.currentDevice.orientation == UIDeviceOrientationLandscapeRight ? 18.0 : 28.0;
    UIEdgeInsets navigationBarLayoutMargins = self.navigationController.navigationBar.layoutMargins;
    CGRect navigationBarFrame = self.navigationController.navigationBar.frame;
    return CGRectMake(navigationBarFrame.size.width-(navigationBarLayoutMargins.right + imageWidth), navigationBarFrame.origin.y + navigationBarLayoutMargins.top, imageWidth, imageHeight);
}

试试这个实现：

@implementation UIBarButtonItem(Extras)

- (CGRect)frameInView:(UIView *)v {

    UIView *theView = self.customView;
    if (!theView.superview && [self respondsToSelector:@selector(view)]) {
        theView = [self performSelector:@selector(view)];
    }

    UIView *parentView = theView.superview;
    NSArray *subviews = parentView.subviews;

    NSUInteger indexOfView = [subviews indexOfObject:theView];
    NSUInteger subviewCount = subviews.count;

    if (subviewCount > 0 && indexOfView != NSNotFound) {
        UIView *button = [parentView.subviews objectAtIndex:indexOfView];
        return [button convertRect:button.bounds toView:v];
    } else {
        return CGRectZero;
    }
}

@end

您应该在子视图上循环，并检查其类型或内容以进行识别。通过kvo访问视图并不安全，您不能确定索引。

看看这个答案：如何将边框和角半径应用于UIBarButtonItem？这说明了如何遍历子视图以查找按钮的框架。

您可以使用自定义视图（即UIButton）创建UIBarButtonItem，然后您可以执行任何操作。：]

在Swift 4.2中并受到luca的启发

extension UIBarButtonItem {

    var frame:CGRect?{
        return (value(forKey: "view") as? UIView)?.frame
    }

}


guard let frame = self.navigationItem.rightBarButtonItems?.first?.frame else{ return }

Swift 4 up当前最好的方法是从以下位置访问其框架：

self.navigationItem.rightBarButtonItems 通过

let customView = navigationItem.rightBarButtonItems?.first?.customView // access the first added customView

这种访问方式比访问私有api安全。

• 在此查看答案：

将CustomView添加到navigationItem之后，CustomView始终返回nil

我在条形按钮项上使用了一个视图，并在视图上使用了一个标签：

for view in bottomToolbar.subviews {
   if let stackView = view.subviews.filter({$0 is UIStackView}).first {
       //target view has tag = 88
       if let targetView = stackView.subviews.filter({$0.viewWithTag(88) != nil}).first {                                
          //do something with target view
   }
}

}

这是这样做的方法：

-(CGRect)findFrameOfBarButtonItem{
    for (UIView *view in self.navigationController.navigationBar.subviews)
    {
       if ([view isKindOfClass:NSClassFromString(@"_UINavigationBarContentView")])
       {
         UIView * barView = [self.navigationItem.rightBarButtonItem valueForKey:@"view"];
         CGRect barFrame = barView.frame;
         CGRect viewFrame = [barView convertRect:barFrame toView:view];
         return viewFrame;
       }
    }

    return CGRectZero;
}