Question

基本上，我有一个测验应用，我添加了问题，然后切换到另一个屏幕，以显示选择后正确答案的扩展版本。我尝试过添加按钮和标签，但是当我这样做时，我最终会在屏幕上显示按钮和标签“重影”，之后我就不再使用了。如何删除所有子视图，以便我在方法中添加的每个按钮和标签都会显示在新屏幕上？

class MyApplicationController < UIViewController

def loadView  
    self.view = UIImageView.alloc.init  
end

def viewDidLoad  
    super  
    view.userInteractionEnabled=true  
    @question_index=0  
    @answerChoices = []  
    @questionChoices=["What is best in life?",...]  
    makeQuestion  
end  

def makeQuestion 
    left =20  
    top=100  
    label = UILabel.new  
    label.text =@questionChoices[@question_index]  
    label.textAlignment = UITextAlignmentCenter  
    label.textColor = UIColor.redColor  
    label.frame = [[20,20], [view.frame.size.width-40, 40]]  
    label.lineBreakMode = UILineBreakModeWordWrap  
    label.numberOfLines = 0  
    label.sizeToFit  
    view.image = UIImage.imageNamed('background.jpg')  
    view.addSubview(label)  
    4.times do |i|  
        @button = UIButton.buttonWithType(UIButtonTypeRoundedRect)  
    @button.setTitle(@answerChoices[i][@question_index], forState:UIControlStateNormal)  
        @button.frame = [[left, top], [view.frame.size.width - left * 2, 40]]  
    @button.addTarget(self, action:'actionTapped:', forControlEvents:UIControlEventTouchUpInside)  
        @button.tag=i  
        top+=45  
        view.addSubview(@button)  
    end  
end

def makeAnswer  
    @button.removeFromSuperview
    @button.removeFromSuperview
    @button.removeFromSuperview
    @button.removeFromSuperview
    view.image = UIImage.imageNamed('back.jpg')
    label = UILabel.new
    label.text =@rightArray[@question_index]
    label.textAlignment = UITextAlignmentCenter
    label.textColor = UIColor.blackColor
    label.frame = [[20,20], [view.frame.size.width-40, 40]]  
    label.lineBreakMode = UILineBreakModeWordWrap  
    label.numberOfLines = 0  
    label.sizeToFit  
    view.addSubview(label)  


    @button = UIButton.buttonWithType(UIButtonTypeRoundedRect)  
    @button.setTitle("More questions", forState:UIControlStateNormal)  
    @button.tag=1  
    @button.addTarget(self, action:'makeQuestion', forControlEvents:UIControlEventTouchUpInside)     
    @button.frame = [[20, 100], [view.frame.size.width - 20 * 2, 40]]  
    view.addSubview(@button)  
end 

end

Answer 1

您需要一组按钮。在4.times循环中，您将覆盖实例变量@button四次。相反，将@button设为一个按钮数组，并为每个索引指定一个不同的按钮。

如果你有一个变量myView并想要删除它的所有子视图，我相信这会有效：

myView.subviews.each {|sv| sv.removeFromSuperview}

如何删除Rubymotion中的所有子视图？

1 个答案: