如何以编程方式创建固定空间和可伸缩空间的工具栏按钮项目？

Question

我希望您能够通过编程创建UIBarButtonItems并在按钮之间放置这些固定空间项。

- Linux world

Answer 1

UIBarButtonItem *fixedItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
fixedItem.width = 20.0f; // or whatever you want

UIBarButtonItem *flexibleItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];

- Jerry Jones

---

请注意，要设置固定间隔的UIBarButtonItem的宽度，需要设置.width属性。 - Nick Forge

完美的答案！ - Pratik Jamariya

我们如何使用代码实现灵活的宽度并在所有按钮之间提供相等的间距？我不想硬编码宽度=20.0。 - Satyam

在每两个按钮之间加入一个灵活的宽度即可。@Satyam - heyfrank

Answer 2

Swift

// Fixed Space
let fixedSpace: UIBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.FixedSpace, target: nil, action: nil)
fixedSpace.width = 20.0

// Flexible Space
let flexibleSpace: UIBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.FlexibleSpace, target: nil, action: nil)

- 365SplendidSuns

Answer 3

UIBarButtonItem *todayItem = [[UIBarButtonItem alloc] initWithTitle:@"Today" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
todayItem.tag = 2;

UIBarButtonItem *cashItem = [[UIBarButtonItem alloc] initWithTitle:@"Cash" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
cashItem.tag = 3;

UIBarButtonItem *creditItem = [[UIBarButtonItem alloc] initWithTitle:@"Credit" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
creditItem.tag = 4;

UIBarButtonItem *allItem = [[UIBarButtonItem alloc] initWithTitle:@"All" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
allItem.tag = 1;

UIBarButtonItem *returnItem = [[UIBarButtonItem alloc] initWithTitle:@"Return" style:UIBarButtonItemStylePlain target:self action:@selector(update_baritem:)];
returnItem.tag = 5;

UIBarButtonItem *fixedItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
[fixedItem setWidth:455.0f];

UIBarButtonItem *fixed2Item = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
[fixed2Item setWidth:37.0f];

UIBarButtonItem *flexibleItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];

[self.toolbar setItems:@[fixed2Item, returnItem, creditItem, cashItem, fixedItem, todayItem, flexibleItem, allItem] animated:NO];

- hans

---

为什么你要将右侧的按钮设置为左侧的项目？这样做只是非常糟糕的风格或者是一个bug，我不知道具体是哪种情况。 - Ben Lachman

Answer 4

截至本文撰写之时，如果你的目标是iOS 14及以上版本，则可以使用相应的类函数更简洁地获取固定和灵活空间项目:

let fixedSpace = UIBarButtonItem.fixedSpace(20)
let flexibleSpace = UIBarButtonItem.flexibleSpace()

文档：固定间距，自动伸缩间距

- Cem Schemel

Answer 5

在Swift中：

let fixedSpace = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
fixedSpace.width = 20.0

- Kiran Jasvanee

Answer 6

Swift 5.1.2

// Fixed Space
let fixedSpace: UIBarButtonItem = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
fixedSpace.width = 20.0

// Flexible Space
let flexibleSpace: UIBarButtonItem = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)

- netsplatter

Answer 7

在Swift 3中，UIBarButtonItem有一个名为init(barButtonSystemItem:target:action:)的初始化方法。init(barButtonSystemItem:target:action:)具有以下声明：

convenience init(barButtonSystemItem systemItem: UIBarButtonSystemItem, target: Any?, action: Selector?)

初始化一个包含指定系统项的新项。

---

UIBarButtonSystemItem是一个枚举类型，包括done、play、add 或 cancel等多个选项。但是，根据您的需要，您也可以选择flexibleSpace或fixedSpace选项。

flexibleSpace选项的声明如下:

在其他项目之间添加空白空间。该空间平均分配给其他项目。当设置此值时，其他项目属性将被忽略。

fixedSpace选项的声明如下:

在其他项目之间添加空白空间。仅在设置此值时使用width属性。

---

因此，您可以根据以下示例以编程方式创建固定和可伸缩的空格栏按钮项：

let flexibleSpace = UIBarButtonItem(
    barButtonSystemItem: UIBarButtonSystemItem.flexibleSpace,
    target: nil,
    action: nil
)

let fixedSpace = UIBarButtonItem(
    barButtonSystemItem: UIBarButtonSystemItem.fixedSpace,
    target: nil,
    action: nil
)
fixedSpace.width = 30 // Set width with the appropriate value

---

作为一个例子，下面的 Playground 代码展示了如何在视图控制器中添加一个底部栏，其中有两个居中的播放和暂停栏按钮项，它们之间有一个固定的间距为30。

import PlaygroundSupport
import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .white
        title = "Home"
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        // Show navigation controller’s built-in toolbar
        navigationController?.setToolbarHidden(false, animated: false)

        // Create UIBarButtonItems
        let flexibleSpace1 = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let playItem = UIBarButtonItem(barButtonSystemItem: .play, target: self, action: nil)
        let fixedSpace = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
        fixedSpace.width = 30
        let pauseItem = UIBarButtonItem(barButtonSystemItem: .pause, target: self, action: nil)
        let flexibleSpace2 = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)

        // Set the view controller toolbar items
        setToolbarItems([flexibleSpace1, playItem, fixedSpace, pauseItem, flexibleSpace2], animated: false)
    }

    override func viewWillDisappear(_ animated: Bool) {
        // Hide navigation controller’s built-in toolbar
        navigationController?.setToolbarHidden(true, animated: true)

        super.viewWillDisappear(animated)
    }

}

let viewController = ViewController()
let navigationController = UINavigationController(rootViewController: viewController)
PlaygroundPage.current.liveView = navigationController

---

使用 View ▸ Assistant Editor ▸ Show Assistant Editor 在 Playground 辅助编辑器中预览您的视图控制器。

- Imanou Petit

Answer 8

在ViewDidLoad方法中：

    //toolbar
UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 416, 320, 44)];

// bar btns
UIBarButtonItem *backBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRewind target:self action:@selector(goBack)];
UIBarButtonItem *forwardBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFastForward target:self action:@selector(goForward)];
UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil];
UIBarButtonItem *bookmarkBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemBookmarks target:self action:@selector(bookmark)];
UIBarButtonItem *refreshBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh)];
UIBarButtonItem *stopLoadingBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemStop target:self action:@selector(stopLoading)];

// add btns to the bar
[toolBar setItems:[NSMutableArray arrayWithObjects:bookmarkBtn,backBtn,forwardBtn,flexibleSpace,refreshBtn,stopLoadingBtn, nil]];

// adds the toobar to the view
[self.view addSubview:toolBar];

不要忘记每个按钮的操作（例如在此示例中为UIWebView）：

    -(void)goBack
{
    [_webView goBack];
}

-(void)goForward
{
    [_webView goForward];
}

etc.

- LAOMUSIC ARTS