paintComponent之後的Java Swing繪製圖像調用

Question

我對如何擴展JPanel以使畫布樣式對象在Swing中工作有點困惑，如果我想要在創建新圖像之後創建新圖像或文本，我該怎麼辦？目的？因爲我認爲這是paintComponent被調用的時候。

Answer 1

除了從ControlAltDel優秀的建議（見step 3 of the tutorial關於如何編程重繪信息）Andrew Thompson和，這可能是一個非常簡單的例子，用於幫助你開始：

public class Main { 
    public static void main(final String[] args) throws InterruptedException { 
     final JFrame frame = new JFrame("Swing canvas"); 
     frame.setBounds(100, 100, 640, 480); 
     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); 
     final CanvasPanel canvasPanel = new CanvasPanel(); 
     frame.getContentPane().add(canvasPanel); 
     frame.setVisible(true); 
     final List<String> words = Arrays.asList("one", "ein", "une", "uno", "jeden", "een"); 
     for (final String word : words) { 
      canvasPanel.addWord(word); 
      // Dirty way to simulate some heavy translation work... 
      Thread.sleep(246); 
     } 
    } 
} 

class CanvasPanel extends JPanel { 
    private final List<String> words = new ArrayList<>(); 

    public void addWord(final String word) { 
     words.add(word); 
     repaint(); 
    } 

    @Override 
    protected void paintComponent(final Graphics graphics) { 
     super.paintComponent(graphics); 
     for (int wordIndex = 0; wordIndex < words.size(); wordIndex++) 
      graphics.drawString(words.get(wordIndex), 42, 64 + 28 * wordIndex); 
    } 
} 

在這例如，畫布面板自身調用重繪方法，但也可以從外部調用。祝你的項目好運！