ios 如何使用 Swift 构建 ScrollView？

How to construct a ScrollView using Swift?

提问by Alex

I'm constructing my first App for IOS and I'm struggling to find a way to do a simple ScrollView using the Swift code on the XCode6, please can someone help me to find the solution?

我正在为 IOS 构建我的第一个应用程序，我正在努力寻找一种方法来使用 XCode6 上的 Swift 代码执行简单的 ScrollView，有人可以帮我找到解决方案吗？

My problem is that I don't know how to make the scrollview work in my code. I already putted the code as you can see below in the ViewController.swift and I was expecting to be able to select the Outlet "scroller" in the Main.storyboard for a ViewController, instead of this I'm receiving the error *"fatal error: Can't unwrap Optional.None (lldb)"* EXC_BAD_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0)

我的问题是我不知道如何使滚动视图在我的代码中工作。我已经把代码放在下面的 ViewController.swift 中，我希望能够在 Main.storyboard 中为 ViewController 选择 Outlet“滚动条”，而不是这个，我收到了错误*"fatal error: Can't unwrap Optional.None (lldb)"* EXC_BAD_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0)

I have some ViewController screens and in one of that I putted one ScrollView and I want to make it works using the Swift.

我有一些 ViewController 屏幕，其中一个我放了一个 ScrollView，我想使用 Swift 让它工作。

I'm stuck on this:

我被困在这个：

import UIKit

class ViewController: UIViewController {

    @IBOutlet var scroller:UIScrollView

    override func viewDidLoad() {
        super.viewDidLoad()
        scroller.scrollEnabled = true;
        scroller.contentSize = CGSizeMake(320, 624);
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

I think if someone can provide a simple example how to do a scrollview using swift it will solve my problem. Any help is appreciate.

我认为如果有人可以提供一个简单的示例，如何使用 swift 进行滚动视图，它将解决我的问题。任何帮助表示赞赏。

Trying to do it in a old style I tried to do it using a .m and .h file:

尝试以旧样式进行操作时，我尝试使用 .m 和 .h 文件进行操作：

ViewController.m

视图控制器.m

#import "Amigo-Bridging-Header.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    [scroller setScrollEnabled:YES];
    [scroller setContentSize:CGSizeMake(320, 624)];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Amigo-Bridging-Header.h

Amigo-Bridging-Header.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController {
    IBOutlet UIScrollView *scroller;
}
@end

Cheers

干杯

回答by Ryan

Let's give this a shot. The one thing to note is I have yet to find a way to downcast self.view as a UIScrollView, so you can't make calls like self.view.contentOffset.

让我们试一试。需要注意的一件事是我还没有找到一种方法将 self.view 向下转换为 UIScrollView，所以你不能像 self.view.contentOffset 这样调用。

import UIKit

class ScrollingViewController : UIViewController {
    // Create a scrollView property that we'll set as our view in -loadView
    let scrollView = UIScrollView(frame: UIScreen.mainScreen().bounds)

    override func loadView() {
        // calling self.view later on will return a UIView!, but we can simply call 
        // self.scrollView to adjust properties of the scroll view:
        self.view = self.scrollView

        // setup the scroll view
        self.scrollView.contentSize = CGSize(width:1234, height: 5678)
        // etc...
    }

    func example() {
        let sampleSubView = UIView()
        self.view.addSubview(sampleSubView) // adds to the scroll view

        // cannot do this:
        // self.view.contentOffset = CGPoint(x: 10, y: 20)
        // so instead we do this:
        self.scrollView.contentOffset = CGPoint(x: 10, y: 20)
    }

}

回答by jrturton

Your outlet is not connected. From the Swift with objective-C book:

您的插座未连接。来自带有 Objective-C的Swift 书：

When you declare an outlet in Swift, the compiler automatically converts the type to a weak implicitly unwrapped optional and assigns it an initial value of nil. In effect, the compiler replaces @IBOutlet var name: Typewith @IBOutlet weak var name: Type! = nil

当你在 Swift 中声明一个 outlet 时，编译器会自动将类型转换为一个弱的隐式解包可选项，并为其分配一个初始值 nil。实际上，编译器替换@IBOutlet var name: Type为@IBOutlet weak var name: Type! = nil

If this value was not connected, it would remain as nil and you'd get a runtime error when accessing the value.

如果此值未连接，它将保持为 nil，并且在访问该值时会出现运行时错误。

回答by Vinod Joshi

 @IBOutlet weak var scrollView: UIScrollView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        // setup the scroll view
        self.scrollView.contentInset = UIEdgeInsetsMake(0, 0, 200, 0);

    }