單選按鈕改變JCombo數據

Question

尋找一種方法來改變輸出到組合框的數據，通過選擇單選按鈕，但是數據被從文本文件中拉出並保存到一個數組中，然後傳回到JCOMBO數組列表。對不起，如果問題是一個很大的含糊不清，我不知道該怎麼說。但文件由兩個不同的TXT文件分開，我可以輕鬆地從中返回數據。

ArrayList<String> stations = Reader("Default.txt"); 

    JComboBox<String> cb = new JComboBox<>(stations.toArray(new String[stations.size()])); 
    JRadioButton belgrave = new JRadioButton("Belgrave Line"); 
    belgrave.addActionListener(new ActionListener(){ 
     public void actionPerformed(ActionEvent e){ 
      cb.removeAllItems(); 
      stations.clear(); 
      ArrayList<String> stations = Reader("Belgrave.txt"); 
      JComboBox<String> cb = new JComboBox<>(stations.toArray(new String[stations.size()])); 
     } 
    }); 
    JRadioButton glenwaverly = new JRadioButton("Glen Waverly Line"); 
    glenwaverly.addActionListener(new ActionListener(){ 
     public void actionPerformed(ActionEvent e){ 
      cb.removeAllItems(); 
      stations.clear(); 
      ArrayList<String> stations = Reader("Glenwaverly.txt"); 
      JComboBox<String> cb = new JComboBox<>(stations.toArray(new String[stations.size()])); 
     } 
    }); 
    ButtonGroup bG = new ButtonGroup(); 
    JButton apply = new JButton("Touch on ?"); 
    JButton cancel = new JButton("Cancel"); 

Answer 1

就像你加入到apply和cancel按鈕，您將需要一個動作監聽器適用於單選按鈕以及動作監聽。

然後做類似下面的事情。

private void jRadioButton1ActionPerformed(java.awt.event.ActionEvent evt) {            
    //suppose this is your file input, that you will have to read 
    String[] test = { "Bird", "Cat", "Dog", "Rabbit", "Pig" }; 
    //your combobox name supposed it is combo 
    //remove all the previous items 
    combo.removeAllItems(); 
    //add all the items of the array(there is no addAll method) 
    for(int i=0; i<test.length; i++) 
     combo.addItem(test[i]); 
} 

希望它有幫助。

請注意，從TXT文件讀取數據並將其解析爲數組與txt的結構有關。看看here如何逐行閱讀一個TXT文件。

---

編輯

在你的聽衆，你要創建一個新的本地組合框。不過cb裏面的聽衆和聽衆之外的cb是不一樣的，它只是一個變量，創建的&只能在方法內部知道。您需要直接調用cb而不創建新對象。

替換此JComboBox<String> cb = new JComboBox<>(stations.toArray(new String[stations.size()]))

與

String[] items = stations.toArray(new String[stations.size()]; 
for(int i=0; i<items.length; i++) 
     cb.addItem(items[i]);