從字符串數組填充java.awt.list

Question

我想從字符串數組填充我的java awt列表。 字符串數組獲取.csv文件中的值。 （時區） e.g 澳大利亞，墨爾本 澳大利亞，悉尼 歐洲，倫敦

注：有兩個列表框。第一個爲地區，第二個爲城市。 這個想法是在用戶選擇第一個區域後進行第二個更新。

我似乎無法能夠從這些值填充列表

任何幫助將不勝感激 感謝

String fileName = "C:\\Users\\Seb\\IdeaProjects\\TimeMachine\\src\\regions.csv"; 
    File file = new File(fileName); 
    try { 
     Scanner inputStream = new Scanner(file); 
     inputStream.useDelimiter(System.getProperty("line.separator")); //Stops the white spaces creating a new entry in array 
     while (inputStream.hasNext()) { 
      String data = inputStream.next(); //gets the whole line 
      String[] arrayLocations = data.split(","); 
      System.out.println(arrayLocations[0]); 
      System.out.println(arrayLocations[1]); 

      listRegion = Arrays.asList(arrayLocations); 
     } 
     inputStream.close(); 

    } catch (FileNotFoundException e) { 
     e.printStackTrace(); 

出現在listRegion = Arrays.asList(arrayLocations);

整個代碼

錯誤

import java.applet.Applet; 
import java.awt.*; 
import java.awt.List; 
import java.io.*; 
import java.util.Arrays; 
import java.util.Scanner; 

public class TimeMachine extends Applet 
{ 
private List listRegion = new List(); 
private List listSubRegion = new List(); 

public void init() 
{ 
    setLayout(new BorderLayout()); 

    Panel buttons = new Panel(new BorderLayout()); 
    buttons.setBackground(Color.cyan); 
    buttons.add(listRegion, BorderLayout.WEST); 
    buttons.add(listSubRegion, BorderLayout.CENTER); 
    add(buttons, BorderLayout.NORTH); 
} 

public void getLocationInfo() 
{ 
    String fileName = "C:\\Users\\Seb\\IdeaProjects\\TimeMachine\\src\\regions.csv"; 
    File file = new File(fileName); 
    try { 
     Scanner inputStream = new Scanner(file); 
     inputStream.useDelimiter(System.getProperty("line.separator")); //Stops the white spaces creating a new entry in array 
     while (inputStream.hasNext()) { 
      String data = inputStream.next(); //gets the whole line 
      String[] arrayLocations = data.split(","); 
      System.out.println(arrayLocations[0]); 
      System.out.println(arrayLocations[1]); 

      listRegion = Arrays.asList(arrayLocations); 
     } 
     inputStream.close(); 

    } catch (FileNotFoundException e) { 
     e.printStackTrace(); 
    } 
} 

}

Answer 1

你混合兩個java.util.List和java.awt.List，只使用java.awt.List：

listRegion = new List(); 
while (inputStream.hasNext()) { 
      String data = inputStream.next(); //gets the whole line 
      String[] arrayLocations = data.split(","); 
      System.out.println(arrayLocations[0]); 
      System.out.println(arrayLocations[1]); 
      for(String location : arrayLocations) 
       listRegion.add(location); 
     } 

更正式地說，下面是一個工作代碼，其中region.csv必須包含地區，國家格式，其中重複的處理方式：

import java.applet.Applet; 
import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.List; 
import java.awt.Panel; 
import java.awt.event.ItemEvent; 
import java.awt.event.ItemListener; 
import java.io.File; 
import java.io.FileNotFoundException; 
import java.util.Arrays; 
import java.util.HashMap; 
import java.util.HashSet; 
import java.util.Map; 
import java.util.Scanner; 
import java.util.Set; 

public class TimeMachine extends Applet implements ItemListener{ 
    private static final long serialVersionUID = 1L; 

    private List listRegion = new List(); 
    private List listSubRegion = new List(); 
    private Map<String, Set<String>> regionCountryMap = new HashMap<String, Set<String>>(); 

    public void init() 
    { 
     setLayout(new BorderLayout()); 

     getLocationInfo(); 
     Panel buttons = new Panel(new BorderLayout()); 
     buttons.setBackground(Color.cyan); 
     buttons.add(listRegion, BorderLayout.WEST); 
     buttons.add(listSubRegion, BorderLayout.CENTER); 
     add(buttons, BorderLayout.NORTH); 
    } 

    private void getLocationInfo() { 
     String fileName = "e:\\regions.csv"; 
     File file = new File(fileName); 
     try { 
      Scanner inputStream = new Scanner(file); 
      inputStream.useDelimiter(System.getProperty("line.separator")); 
      listRegion = new List(); 
      while (inputStream.hasNext()) 
      { 
       String data = inputStream.next(); // gets the whole line 
       String[] arrayLocations = data.split(","); 
       if(arrayLocations.length != 2){ 
        System.out.println("Invalid entry in file : "+ Arrays.toString(arrayLocations)); 
        continue; 
       } 
       String region = arrayLocations[0]; 
       if(!regionCountryMap.containsKey(region)) 
       { 
        listRegion.add(region); 
        regionCountryMap.put(region, new HashSet<String>()); 
       } 
       regionCountryMap.get(region).add(arrayLocations[1]);//Set handles duplicates as well 
      } 
      inputStream.close(); 
      System.out.println("Region, Country list has been parsed successfully"); 
      listRegion.addItemListener(this); 
     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
     } 
    } 

    @Override 
    public void itemStateChanged(ItemEvent e) { 
     Set<String> countries = regionCountryMap.get(listRegion.getSelectedItem()); 
     listSubRegion.removeAll(); 
     for(String country : countries) { 
      listSubRegion.add(country); 
     } 
     listSubRegion.validate(); 
     listSubRegion.repaint(); 
    } 
}