Question

我遇到组件中所选行的问题我有一个带有2个组件和5行的选择器视图我希望它转换单元。麻烦的是，当我尝试向下滚动开关语句不起作用。唯一有效的是var秒。如果我尝试Hectare - ＆gt;正方形英寸它正确转换它，但如果我尝试英亩 - ＆gt;平方英寸它给我与公顷相同的答案 - ＆gt;方英寸。此外，当我添加尝试添加另一个selectedRowInComponent（2）时，应用程序崩溃。

Acre                    Acre
Hectare                 Hectare
Square Inch             Square Inch     
Square Meter            Square Meter
Square Kilometer        Square Kilometer
Square Foot             Square Foot

这是我正在使用的代码

    var one: NSInteger = onlyPicker.selectedRowInComponent(0)
    var second: NSInteger = onlyPicker.selectedRowInComponent(1)



        switch (one) {



        case 0:

            answerField2.text = answerField1.text




        case 1:



            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 2.4711

            var answer = num1 / num2

            var display = answer.description

            answerField2.text = display



        case 2:



            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 6272600

            var answer = num1 * num2

            var display = answer.description

            answerField2.text = display




        case 3:

            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 0.00023711

            var answer = num1 / num2

            var display = answer.description

            answerField2.text = display

        case 4:

            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 247.11

            var answer = num1 / num2

            var display = answer.description

            answerField2.text = display




        case 5:

            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 43560

            var answer = num1 * num2

            var display = answer.description

            answerField2.text = display




        default:

            println("not a value")



        }
        switch (second) {

        case 0:




            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 2.4711

            var answer = num1 * num2

            var display = answer.description

            answerField2.text = display



        case 1:



            answerField2.text = answerField1.text




        case 2:



            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 15500000

            var answer = num1 / num2

            var display = answer.description

            answerField2.text = display


        case 3:

            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 0.00010000

            var answer = num1 / num2

            var display = answer.description

            answerField2.text = display



        case 4:

            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 100

            var answer = num1 / num2

            var display = answer.description

            answerField2.text = display





        case 5:

            var num1 = (answerField1.text as NSString).floatValue

            var num2:Float = 107640

            var answer = num1 * num2

            var display = answer.description

            answerField2.text = display


        default:

            println("not a value")






        }

    }

    }

Answer 1

在崩溃问题上，如果它崩溃了这样的代码，那么请检查UIPicker上的numberOfComponents属性。如果它被设置为2 - 则那就是问题。

var third: NSInteger = onlyPicker.selectedRowInComponent(2)

在计算中，如下重新分解代码将消除switch语句。转换变量是一个Float类型的数组数组（使用新的Swift样式 - 从Xcode 6 Beta 3开始）。

我列出了转换值的名称，以说明如何设置/填充数组。这些应该用Float值替换。

var conversions: [[Float]] = [ [acre-to-acre,acre-to-hectace,acre-to-square-inch,....], 
                               [hectacre-to-acre,hectacre-tohectacre,hectacre-to-square-inch,...],
                               [square-inch-to-acre,square-inch-to-hectacre,...]
                               ....
                             ]


var one: NSInteger = onlyPicker.selectedRowInComponent(0)
var second: NSInteger = onlyPicker.selectedRowInComponent(1)

var num1 = (answerField1.text as NSString).floatValue

var conversionFactor:Float = conversions[one][two]

var answer = num1 * conversionFactor

var display = answer.description

answerField2.text = display

在swift中使用selectedrowincomponenet函数时出现问题

1 个答案: