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轉換ArrayList <ArrayList<Object> &gt;轉到對象[] []

[英]Convert ArrayList<ArrayList<Object>> to Object[][]

我想用cnstructor填充一個JTable:

new JTable(datas, columns);

所以我需要一個Object[]作為列,而Object[][]作為數據。 問題是當我嘗試獲取數據時。

在我的方法之一中,我使用了ArrayList<ArrayList<Object>> ,我想將其轉換為Object[][]

這是我的代碼示例:

ArrayList<ArrayList<Object>> datas = new ArrayList<ArrayList<Object>>();

for (Map.Entry<Integer, JSObject> entry : params.entrySet()) {
    datas.add(entry.getValue().getValues()); // getValues returns an ArrayList<Object>
}

return new datas.toArray(); //  not seems to work

我在這個問題中看到了將ArrayList <Object []>轉換為Object [] []的一些想法,但是我不確定結果如何。

提前致謝 !

您不能只是將datas類型更改為ArrayList<Object[]> ,並且每次添加元素時都使用toArray()

ArrayList<Object[]> datas = new ArrayList<Object[]>();
for (Map.Entry<Integer, JSObject> entry : params.entrySet()) {
    datas.add(entry.getValue().getValues().toArray());
}
return datas.toArray(new Object[][]{});

轉換 ArrayList<object> 串起來<div id="text_translate"><p>嗨,我正在嘗試練習 java,我才剛剛開始。 為了練習,我正在嘗試構建一個簡單的撲克游戲,但遇到了卡片數組列表,我正在嘗試將其打印出來,但只有控制台的地址是 output。 自然我嘗試使用.toString 方法並創建我自己的toString 方法來嘗試檢查數組列表是否輸入正確。 Bellow 是我的卡片 class 和 Arraylist{Card}Deck。 貝婁是我的代碼</p><pre>package poker; import java.util.ArrayList; public class Card { private String _suit; private int _cardNum; public Card(int cardNum, String suit) { _suit = suit; _cardNum = cardNum; } public String toString() { return _suit +_cardNum; } static ArrayList&lt;`enter code here`Card&gt; Deck = new ArrayList&lt;Card&gt;() {{ add(new Card(0,"Hearts")); add(new Card(1,"Hearts")); add(new Card(1,"Hearts")); add(new Card(2,"Hearts")); add(new Card(3,"Hearts")); add(new Card(4,"Hearts")); add(new Card(5,"Hearts")); add(new Card(6,"Hearts")); add(new Card(7,"Hearts")); add(new Card(8,"Hearts")); add(new Card(9,"Hearts")); add(new Card(10,"Hearts")); add(new Card(11,"Hearts")); add(new Card(12,"Hearts")); add(new Card(13,"Hearts")); add(new Card(0,"Spades")); add(new Card(1,"Spades")); add(new Card(2,"Spades")); add(new Card(3,"Spades")); add(new Card(4,"Spades")); add(new Card(5,"Spades")); add(new Card(6,"Spades")); add(new Card(7,"Spades")); add(new Card(8,"Spades")); add(new Card(9,"Spades")); add(new Card(10,"Spades")); add(new Card(11,"Spades")); add(new Card(12,"Spades")); add(new Card(13,"Spades")); add(new Card(0,"Clubs")); add(new Card(1,"Clubs")); add(new Card(2,"Clubs")); add(new Card(3,"Clubs")); add(new Card(4,"Clubs")); add(new Card(5,"Clubs")); add(new Card(6,"Clubs")); add(new Card(7,"Clubs")); add(new Card(8,"Clubs")); add(new Card(9,"Clubs")); add(new Card(10,"Clubs")); add(new Card(11,"Clubs")); add(new Card(12,"Clubs")); add(new Card(13,"Clubs")); add(new Card(0,"Diamonds")); add(new Card(1,"Diamonds")); add(new Card(2,"Diamonds")); add(new Card(3,"Diamonds")); add(new Card(4,"Diamonds")); add(new Card(5,"Diamonds")); add(new Card(6,"Diamonds")); add(new Card(7,"Diamonds")); add(new Card(8,"Diamonds")); add(new Card(9,"Diamonds")); add(new Card(10,"Diamonds")); add(new Card(11,"Diamonds")); add(new Card(12,"Diamonds")); add(new Card(13,"Diamonds")); }}; }</pre><p> 和我的 MainApp</p><pre> package poker; import java.util.Random; import static java.lang.System.out; public class MainApp { public static void main(String[] args) { for(int i = 0;i &lt;Card.Deck.size();i++) { out.println(Card.toString()); } } }</pre><p> 在打印行中是我的問題發生的地方。 如何將 arraylist 從 class 類型轉換為用於輸出的字符串? 提前致謝!</p></div></object>

[英]Convert ArrayList<Object> to string

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相關問題 將object [] []轉換為ArrayList <Object[]> 將ArrayList <Object []>轉換為Object [] [] 轉換ArrayList <Object[]> 反對[] 轉換數組列表<Object>到 ArrayList<AnotherType> 轉換ArrayList <String> 到ArrayList <Object> 如何轉換ArrayList <Object> 到ArrayList <different Object> 無法轉換ArrayList <ArrayList<Integer> &gt;到ArrayList <ArrayList<Object> &gt; 將ArrayList轉換為json對象 將byte []轉換為ArrayList <Object> 轉換 ArrayList<object> 串起來<div id="text_translate"><p>嗨,我正在嘗試練習 java,我才剛剛開始。 為了練習,我正在嘗試構建一個簡單的撲克游戲,但遇到了卡片數組列表,我正在嘗試將其打印出來,但只有控制台的地址是 output。 自然我嘗試使用.toString 方法並創建我自己的toString 方法來嘗試檢查數組列表是否輸入正確。 Bellow 是我的卡片 class 和 Arraylist{Card}Deck。 貝婁是我的代碼</p><pre>package poker; import java.util.ArrayList; public class Card { private String _suit; private int _cardNum; public Card(int cardNum, String suit) { _suit = suit; _cardNum = cardNum; } public String toString() { return _suit +_cardNum; } static ArrayList&lt;`enter code here`Card&gt; Deck = new ArrayList&lt;Card&gt;() {{ add(new Card(0,"Hearts")); add(new Card(1,"Hearts")); add(new Card(1,"Hearts")); add(new Card(2,"Hearts")); add(new Card(3,"Hearts")); add(new Card(4,"Hearts")); add(new Card(5,"Hearts")); add(new Card(6,"Hearts")); add(new Card(7,"Hearts")); add(new Card(8,"Hearts")); add(new Card(9,"Hearts")); add(new Card(10,"Hearts")); add(new Card(11,"Hearts")); add(new Card(12,"Hearts")); add(new Card(13,"Hearts")); add(new Card(0,"Spades")); add(new Card(1,"Spades")); add(new Card(2,"Spades")); add(new Card(3,"Spades")); add(new Card(4,"Spades")); add(new Card(5,"Spades")); add(new Card(6,"Spades")); add(new Card(7,"Spades")); add(new Card(8,"Spades")); add(new Card(9,"Spades")); add(new Card(10,"Spades")); add(new Card(11,"Spades")); add(new Card(12,"Spades")); add(new Card(13,"Spades")); add(new Card(0,"Clubs")); add(new Card(1,"Clubs")); add(new Card(2,"Clubs")); add(new Card(3,"Clubs")); add(new Card(4,"Clubs")); add(new Card(5,"Clubs")); add(new Card(6,"Clubs")); add(new Card(7,"Clubs")); add(new Card(8,"Clubs")); add(new Card(9,"Clubs")); add(new Card(10,"Clubs")); add(new Card(11,"Clubs")); add(new Card(12,"Clubs")); add(new Card(13,"Clubs")); add(new Card(0,"Diamonds")); add(new Card(1,"Diamonds")); add(new Card(2,"Diamonds")); add(new Card(3,"Diamonds")); add(new Card(4,"Diamonds")); add(new Card(5,"Diamonds")); add(new Card(6,"Diamonds")); add(new Card(7,"Diamonds")); add(new Card(8,"Diamonds")); add(new Card(9,"Diamonds")); add(new Card(10,"Diamonds")); add(new Card(11,"Diamonds")); add(new Card(12,"Diamonds")); add(new Card(13,"Diamonds")); }}; }</pre><p> 和我的 MainApp</p><pre> package poker; import java.util.Random; import static java.lang.System.out; public class MainApp { public static void main(String[] args) { for(int i = 0;i &lt;Card.Deck.size();i++) { out.println(Card.toString()); } } }</pre><p> 在打印行中是我的問題發生的地方。 如何將 arraylist 從 class 類型轉換為用於輸出的字符串? 提前致謝!</p></div></object>
 
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