swift - UIPickerView 的使用

效果顯示數下圖：

1、初始化

pickerView.center = self.view.center
//將dataSource設置成自己
pickerView.dataSource=self
//將delegate設置成自己
pickerView.delegate=self
//設置選擇框的默認值
pickerView.selectRow(2,inComponent:0,animated:true)
pickerView.selectRow(4,inComponent:1,animated:true)
pickerView.selectRow(5,inComponent:2,animated:true)
self.view.addSubview(pickerView)

2、代理方法的實現

func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 3
    }
    
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return 9
    }

 

//設置選擇框個選項的內容
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return String(row)+"_"+String(component)
    }

3、觸摸按鈕時，獲得被選中的索引

   func btnClick() {

        let strs = String(pickerView.selectedRowInComponent(0)) + "_" + String(pickerView.selectedRowInComponent(1)) + "_" + String(pickerView.selectedRowInComponent(2))
        
         let alertControllers = UIAlertController(title: "系統提示",message: strs,preferredStyle: .alert)
        let cancelActions = UIAlertAction(title: "取消",style: .cancel,handler: nil)
        let okActions = UIAlertAction(title: "確定",style: .default,handler: nil)
        alertControllers.addAction(cancelActions)
        alertControllers.addAction(okActions)
        
        self.present(alertControllers, animated: true, completion: nil)
    }

4、調整選擇框的尺寸

func pickerView(pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
        if 0 == component
        {
            //第一列變寬
            return 100
        }else
        {
            //第二、三列變寬
            return 50
        }
    }

 

5、設置行高

 func pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
        return 40
    }

6、檢測響應選項的選擇狀態

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        //將在滑動停止后觸發，並打印出選中列和行索引
        print(component)
        print(row)
    }

7,將圖片作為選擇框選項

    //將圖片作為選擇框選項
    //選擇框選擇的內容，除了可以是字符串類型的，還可以是任意UIView類型的元素，比如我們將選項內容設置為圖片：
   func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
        let  image = UIImage(named:"11")
        let himageView = UIImageView()
        himageView.frame = CGRect(x:5,y:0,width:30,height:30)
        himageView.image = image
        
        return himageView
    }

 

 點擊按鈕，顯示被選中的行數，效果圖如下：