Question

我想知道如何添加按钮（左和右）来更改页面控件视图。我正在研究这个教程[1]：http://www.edumobile.org/iphone/iphone-programming-tutorials/pagecontrol-example-in-iphone/。除了此示例代码中的交换功能外，如何添加2个简单按钮（左和右）来翻页？

我是程序员初学者，所以任何一种答案都是高度评价的！：）

谢谢！

Answer 1

您可以向视图添加两个按钮，当单击该按钮时，请根据单击的按钮调用方法来翻页。

UIButton *leftButton = [[UIButton alloc] init];
leftbutton.frame = leftButtonFrame;
[leftbutton setTitle:@"Left" forState:UIControlStateNormal];
[leftbutton addTarget:self action:@selector(leftbuttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[yourView addSubview:leftbutton];


UIButton *rightButton = [[UIButton alloc] init];
rightButton.frame = rightButtonFrame;
[rightButton setTitle:@"Right" forState:UIControlStateNormal];
[rightButton addTarget:self action:@selector(rightButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
[yourView addSubview:rightButton];

- (void)leftButtonclicked:(id)sender
{
//Code to turn page left
}

- (void)rightButtonclicked:(id)sender
{
//Code to turn page right
}

Answer 2

我会快速回答这个问题，但你应该能够翻译。

过程是找到PageControl视图，添加两个按钮并在适当时隐藏按钮（即第一页上没有上一个按钮）。

我将按钮放在PageControl的左侧和右侧。默认行为是触摸页面返回页面前进。所以我将按钮设置为enabled = false，以便触摸执行此默认行为。

首先我们需要一个枚举来帮助定位按钮。使用不会在其他地方使用的值。

enum enumBtnTag: Int {
    case tagPrev = 9991
    case tagNext = 9992

}

var pageNbr = 0  //Needed to keep track of page being displayed

现在我们将在ViewDidLoad中添加我们的按钮。首先，我找到PageControl，然后我寻找按钮，以便不创建两次。（可以多次调用ViewDidload）

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    for view in self.view.subviews {
        if view is UIPageControl {
            let curr:UIPageControl = view as! UIPageControl
            curr.backgroundColor = UIColor.clear
            curr.currentPageIndicatorTintColor = UIColor.red   //Page Dot is red
            curr.pageIndicatorTintColor = UIColor.black   //Other dots are black

            let pcSz = view.frame
            let btnSz = CGSize(width: 35, height: 50)  //Use your button size


            if let _ = self.view.viewWithTag(enumBtnTag.tagNext.rawValue) as? UIButton {}
            else {   //Next Button not found
                let Nbtn = UIButton(frame: CGRect(x: pcSz.width - btnSz.width, y: -15, width: btnSz.width, height: btnSz.height))
                Nbtn.setTitle(">>", for: UIControlState.normal)
                Nbtn.backgroundColor = UIColor.clear
                Nbtn.setTitleColor(UIColor.brown, for: UIControlState.normal)
                Nbtn.titleLabel?.font = UIFont(name: enumFontNames.MarkerFelt_Wide.rawValue, size: 60.0)
                Nbtn.isEnabled = false  //Allows touch to fall through to PageControl
                Nbtn.tag = enumBtnTag.tagNext.rawValue

                view.addSubview(Nbtn)

            }


            if let _ = self.view.viewWithTag(enumBtnTag.tagPrev.rawValue) as? UIButton {}
            else {   //Prev Button not found
                let Pbtn = UIButton(frame: CGRect(x: 0, y: -15, width: btnSz.width, height: btnSz.height))
                Pbtn.setTitle("<<", for: UIControlState.normal)
                Pbtn.backgroundColor = UIColor.clear
                Pbtn.setTitleColor(UIColor.brown, for: UIControlState.normal)
                Pbtn.titleLabel?.font = UIFont(name: enumFontNames.MarkerFelt_Wide.rawValue, size: 60.0)
                Pbtn.isEnabled = false
                Pbtn.isHidden = true
                Pbtn.tag = enumBtnTag.tagPrev.rawValue

                view.addSubview(Pbtn)
            }
        }
    }

}

然后我捕获将要显示的页面。页面可能不会显示（用户没有拖得足够远），但稍后会处理。

func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {

    if let identifier = pendingViewControllers[0].restorationIdentifier {
        if let index = pages.index(of: identifier) {
            pageNbr = index
        }
    }

}

现在我们修改didFinishAnimating中的按钮;

func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {

    if finished && completed {

        if let button = self.view.viewWithTag(enumBtnTag.tagPrev.rawValue) as? UIButton {
            if pageNbr > 0 {
                button.isHidden = false
            } else {
                button.isHidden = true
            }
        }


        if let button = self.view.viewWithTag(enumBtnTag.tagNext.rawValue) as? UIButton {
            if pageNbr < pages.count - 1 {
               button.isHidden = true
            } else {
               button.isHidden = false
            }
        }

    }

}

奖金代码：我在最后一页添加了一个保存功能，其中包含下一个按钮。您需要设置按钮已启用（因此它会记录触摸）并设置目标（您想要执行的功能）;我的是＆＃34; nextSegue＆＃34;。当然，当不在最后一页时删除目标;

if pageNbr < pages.count - 1 {
    //Not on last page. Use next button
    button.setTitle(">>", for: UIControlState.normal)
    button.removeTarget(self, action:  #selector(nextSegue), for: UIControlEvents.touchUpInside)
    button.isEnabled = false
} else {
    //On last page. Use save button
    button.setTitle("S", for: UIControlState.normal)
    button.addTarget(self, action: #selector(nextSegue), for: UIControlEvents.touchUpInside)
    button.isEnabled = true
}

希望这有助于某人。

如何向页面控制器添加按钮

2 个答案: