使用线程更改数组中按钮的颜色 [英] Changing color of buttons in array using thread

问题描述

我想循环遍历一组按钮，并在迭代数组时将其颜色改变3次。当我单击数组的第一个按钮时，它会改变其余颜色，就像我想要的那样。当我再次尝试时，它不会在我的run（）方法中运行try块。



这是代码。

I want to loop through an array of buttons, and change their colors 3 times as iterate through the array. When i click the first button of the array, it changes the colors of the rest, as i want it to. When i go and try it again, it does not run the try block in my run() method.

Here is the code.

public class ButtonWindow extends JFrame implements Runnable {
	private JPanel topPanel = new JPanel(new GridBagLayout());
	JButton[] listButtons = new JButton[5];
	private Thread t;
	
	public void run() {
	      System.out.println("Running thread");
	      try {
	         for(int i = 1; i < listButtons.length; i++) {
	            System.out.println("Thread changing colors");
	      
					listButtons[i].setBackground(Color.YELLOW);
					Thread.sleep(1000);
					listButtons[i].setBackground(Color.ORANGE);
					Thread.sleep(1000);
					listButtons[i].setBackground(Color.RED);
					Thread.sleep(1000);
					listButtons[i].setBackground(null);
					
	         }
	     } catch (InterruptedException e) {
	         System.out.println("Thread interrupted.");
	     }
	     System.out.println("Thread closing.");
	   }//close run() method
	
	public void start(){
		System.out.println("Starting thread ");
		if(t == null){
			t = new Thread(this);
			t.start();
		}
	}//close start() method
	
	//CONSTRUCTOR
	public ButtonWindow(){
		//create the buttons
		for(int i = 0; i < 5; i++){
			 listButtons[i] = new JButton(String.valueOf(i));
		 }
		setSize(400,400);
		setTitle("Colors");
		setLocationRelativeTo(null);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
		buildTopPanel();
		//BUTTON LISTENERS/////////////////////////////////////////////////////////////////////////////////		
		listButtons[0].addActionListener(new ActionListener(){
			@Override
			public void actionPerformed(ActionEvent arg0) {
				 System.out.println("Creating thread");
			      start();
			}
		});
		//BUTTON LISTENERS END///////////////////////////////////////////////////////////////////	
	}//CLOSE CONSTRUCTOR

	//CREATE PANEL
	public void buildTopPanel(){
		
		GridBagConstraints gc = new GridBagConstraints();
		gc.gridx = 0;
		gc.gridy = 0;
		for(int i = 0; i < 5; i++){
			 //listButtons[i] = new JButton(String.valueOf(i));
			 gc.insets = new Insets(5, 10,0,0);
			 topPanel.add(listButtons[i],gc);
			 gc.gridy ++;
		 }
		add(topPanel,BorderLayout.NORTH);
	}  
}//CLOSE CLASSS

推荐答案

那是因为 t 不是 null 第二个你运行 start 方法的时间，所以线程永远不会再次启动。



尝试设置 t 到 null 在运行方法的末尾，这将允许颜色循环重启。



希望这会有所帮助，

Fredrik

That's because t is not null the second time you run your start method, so the thread never get's started again.

Try setting t to null at the end of the run method, that will allow the color-cycling to restart.

Hope this helps,
Fredrik

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