小编dip*_*dip的帖子

在浏览界面构建器上查找Xcode9 Beta Found Safe Area时查看层次结构查看器.好奇并试图了解苹果上的安全区文档,主要是文档说"与Auto布局直接交互的视图区域"但它不满足我,我想知道这个新事物的实际用途.

有人有一些线索吗？

结论段落来自Apple doc for Safe area.

UILayoutGuide类旨在执行先前由虚拟视图执行的所有任务,但是以更安全,更有效的方式执行.布局指南不定义新视图.它们不参与视图层次结构.相反,他们只是在他们自己的视图的坐标系中定义一个矩形区域,可以与自动布局进行交互.

我按照下面的编程方式创建了UISearchBar,按钮看起来是第二个图像.如何清除搜索栏的白色并将背景颜色设置为黑色

var categorySearchBar : UISearchBar = UISearchBar()
        categorySearchBar.frame = CGRectMake(0, 20, self.view.frame.size.width, 30)
        categorySearchBar.layer.borderColor = UIColor.grayColor().CGColor
        categorySearchBar.layer.borderWidth = 1.0
        categorySearchBar.placeholder = "SEARCH"
        categorySearchBar.barTintColor = UIColor.blackColor()
        self.view.addSubview(categorySearchBar)

我正在尝试在UINavigationBar右侧添加自定义视图.我尝试的是以下内容,但视图没有显示出来!请帮助,提前谢谢!

let viewOnrightButton = UIView(frame: CGRect(x: 2, y: 2, width: 60, height: 22))
 // viewOnrightButton.frame = CGRectMake(2, 2, 60, 22)
viewOnrightButton.layer.cornerRadius = 2
viewOnrightButton.backgroundColor = UIColor(red: 0.961, green: 0.827, blue: 0.239, alpha: 1.00)

lblNumbersOfBanana.frame = CGRectMake(2, 1, viewOnrightButton.frame.width-20, 20)
lblNumbersOfBanana.text = "001"

var bananaImgView = UIImageView(frame: CGRect(x: viewOnrightButton.frame.width-22, y: 0, width: 20, height: 20))
 //  bananaImgView.frame = CGRectMake(viewOnrightButton.frame.width-22, 0, 20, 20)
bananaImgView.image = UIImage(named: "banana")

viewOnrightButton.addSubview(lblNumbersOfBanana)
viewOnrightButton.addSubview(bananaImgView)

self.navigationItem.rightBarButtonItem?.customView = viewOnrightButton

我正在尝试使用swift中的playground创建自定义委托.但是,不通过回调调用doSomething方法.似乎委托？.doSomething()不会触发XYZ类doSomething方法.提前致谢!

import UIKit

@objc protocol RequestDelegate
{
    func doSomething();

      optional  func requestPrinting(item : String,id : Int)
}


class ABC
{
    var delegate : RequestDelegate?
     func executerequest() {

        delegate?.doSomething()
        println("ok delegate method will be calling")
    }
}   

class XYZ : RequestDelegate
{  
    init()
    {
        var a  = ABC()
        a.delegate = self
    }

     func doSomething() {
       println("this is the protocol method")
    }
}    

var a = ABC()
a.executerequest()

我在静态表视图中添加了一些textField和textView.代码很好,并运行在xcode 6.4/ios 8.*但它抛出异常,我无法跟踪.现在我在xcode 7.2上调试代码(swift2.2)

我尝试过设置符号和特殊的断点,但没有运气:(

以下是崩溃的堆栈跟踪,提前感谢您的宝贵帮助.

2015-12-14 16:07:07.989 TuteMate[3380:90711] -[NSNull length]: unrecognized selector sent to instance 0x10ccc6af0 

从特殊的断点:

CoreFoundation`-[NSObject(NSObject) doesNotRecognizeSelector:]:
->  0x10504e3c0 <+0>:   pushq  %rbp
    0x10504e3c1 <+1>:   movq   %rsp, %rbp
    0x10504e3c4 <+4>:   pushq  %r15
    0x10504e3c6 <+6>:   pushq  %r14
    0x10504e3c8 <+8>:   pushq  %rbx
    0x10504e3c9 <+9>:   pushq  %rax
    0x10504e3ca <+10>:  movq   %rdx, %r14
    0x10504e3cd <+13>:  movq   %rdi, %rbx
    0x10504e3d0 <+16>:  movq   0x216c79(%rip), %rsi      ; "class"
    0x10504e3d7 <+23>:  callq  *0x229e1b(%rip)           ; …

在使用GUI Builder时,如何在netbeans中使用像eclipse这样的较短代码？例如

Jbutton btnCalculate = new javax.swing.JButton();

是自动生成但我想要更短的代码,如在eclipse中

Jbutton btnCalculate = new JButton();

在创建按钮的同时!