一、UIPickerView的使用和介紹

UIPickerView是一個選擇器控件，它比UIDatePicker更加通用，它可以生成單列的選擇器，也可生成多列的選擇器，而且開發(fā)者完全可以自定義選擇項的外觀，因此用法非常靈活。UIPickerView直接繼承了UIView，沒有繼承UIControl，因此，它不能像UIControl那樣綁定事件處理方法，UIPickerView的事件處理由其委托對象完成。使用UIPickerView的對象應該遵守UIPickerViewDataSource,UIPickerViewDelegate。

二、UIPickerView 的初始化

let pickerView = UIPickerView.init(frame: CGRect.init(x: 100, y: 80, width: 200, height: 200))
/*
 設置兩個代理
 */
pickerView.dataSource = self
pickerView.delegate = self
/*
 設置背景色
 */
pickerView.backgroundColor = UIColor.gray
/*
 是否顯示默認選中的Row背景處于高亮的狀態(tài)
 false : 為默認
 true  : 高亮狀態(tài)
 */
pickerView.showsSelectionIndicator = true//(iOS13.0later被廢棄)
/*
 渲染到視圖上
 */
self.view.addSubview(pickerView)

三、 UIPickerView的代理

// MARK: 代理事件的實現(xiàn)
// TODO:這是返回每一Row的寬度
func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
     return 200.0
}
//TODO: 設置每一個Row的高度
func pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
    return 60.0
}

// TODO:這是選擇哪一個Row,調(diào)用的函數(shù)
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    print("我選擇了第"+"\(row)"+"行")
}

// TODO: 返回每一個Row的文本
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return (SourceData.object(at: row) as! String)
}

// TODO: 可以設置哪一行顯示特定的樣式
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
    // 創(chuàng)建一個對象
    let specificView = UIView.init()
    specificView.frame = CGRect.init(x: 10, y: 5, width: 100, height: 60)
    specificView.backgroundColor = UIColor.magenta
    /**
     創(chuàng)建一個標題
     */
    let specificLable = UILabel.init(frame: CGRect.init(x: 5, y: 0, width: 90, height: 60))
    specificLable.text = (SourceData[row] as! String)
    specificLable.textColor = UIColor.white
    specificView.addSubview(specificLable)
    return specificView
}

// TODO : 設置每個Row的文本顯示的樣式參數(shù)
func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    /**
     我們要第四行，顯示紅色，并18號字體
     */
    let attributedString = NSAttributedString.init(string:(SourceData[row] as! String), attributes: [NSFontAttributeName:UIFont.boldSystemFont(ofSize: 18),NSForegroundColorAttributeName:UIColor.red])
    return  attributedString
}

//MARK : UIPickerViewDataSource 的代理事件
// TODO: 返回列表的組數(shù)
func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}
// TODO : 這是設置返回列表的個數(shù)
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return SourceData.count
}

四、設置數(shù)據(jù)

func createDataSource() {
    SourceData = ["安其拉","白起","不知火舞","妲己","狄仁杰","典韋","韓信","老夫子","劉邦","劉禪","魯班七號","墨子","孫臏","孫尚香","孫悟空","項羽","亞瑟","周瑜"]
}

五 、UIPickerView的一些get 屬性介紹

/**
 `獲取返回組的個數(shù)`
 */
let rowCount =pickerView.numberOfComponents
print(rowCount)

/**
 `設置指定組，返回的row的個數(shù)`
 */
pickerView.numberOfRows(inComponent: 1)

/**
 `獲取某一組的大小`
 */
let componentSize =  pickerView.rowSize(forComponent: 1)
print(componentSize.width,componentSize.height)

4、獲取指定組的指定列的View

/**
 獲取指定組和指定列的View
 */
let NwComponentRowView = pickerView.view(forRow: 2, forComponent: 1)
NwComponentRowView?.backgroundColor = UIColor.brown

5、UIPickerView的數(shù)據(jù)更新

/**
` 更新所有組的數(shù)據(jù)`
 */
pickerView.reloadAllComponents()

/**
 `更新指定組的數(shù)據(jù)`
 */
pickerView.reloadComponent(1)

/**
 `指定選中某一組的某一行`
 */
pickerView.selectRow(3, inComponent: 1, animated: true)

/**
 `獲取指定組的哪一行被選中`
 */
let NwSelecdRow = pickerView.selectedRow(inComponent: 1)
print(NwSelecdRow)