Question

我在更新gui时遇到问题，因为模拟模型的内部状态发生了变化。类模拟器运行一定数量的步骤。每一步计算机的内部状态都会发生变化。 Gui然后得到通知，并应重新绘制其计算机的图形表示，包括当前状态的文本。不幸的是，对于下面详述的类，gui仅在模拟运行的最后一步之后更新更改。我正在使用观察者（计算机）和可观察（GUICanvas）模式。我做错了什么，GUI不会在模拟的中间步骤重绘？

public class NwSim {


   public NwSim() {
   }

   public static void main(String[] args) {
       JFrame frame;
       Simulator simulator = new Simulator();    
       canvas = new GUICanvas();         //create gui  canvas, which paints guy computers
       canvas.setBackground(Color.white);
       contentPane.add(canvas, BorderLayout.CENTER);
       frame.pack();
       frame.setVisible(true);
   simulator.simulate();
   }
}

//represents the controller in the simulation
public class Simulator {
List<Computer> computers;
private int simulationSteps;

public Simulator()
    simulationSteps = 200;
              computers = new ArrayList<Computer>();


    public void simulate() {
        for(int step = 0; step < simulationSteps; step++) {
        for(Computer computer : computers) {
        computer.tick()
    }
    }
    }

    public Computer createComputer() {
    Computer computer = new Computer();
    computers.add(computer)
    }
}



public class Computer extends Observable {

    public void tick {
    ….. // update field state of the computer
        if (state.stateChanged()) {
            setChanged();
            notifyObservers();    //notify observer- gui canvas that the state of computer has changed and it is time to repaint guiComputers 

        }
 }

 public string getState() {
return state;
 }
}

public class GUIComputer  {

 private static final long serialVersionUID = 1L;
 private int width;
 private int height;   
 private Image image;
 private Computer computer; 


 public GUIComputer(int x, int y, Computer computer component, Image image) {
     this.computer = computer;
     setX(x);
     setY(y);
     this.image = image;
     width = image.getWidth(null);
     height = image.getHeight(null);
 }


 @Override
 public void drawGuiComputer(Graphics g){
        g.drawImage(image, getX(), getY(), null);
        Graphics2D g2 = (Graphics2D)g;
        g2.drawString(computer.getState().toString(), getX() + 20, getY()    // repaint the state for each guiComputer taken from Computer 
                + height + 10);
}
}

public class GUICanvas extends JPanel implements  Observer { 

//
private List<GUIComputer> guiComputers;

public GUICanvas(Simulator simulator)  {
     this.guiComputers = new ArrayList<GUIComputer>();
    // create guy computers using method createGuiComputer below , code omitted
}

public createGuiComputer(Transferable transferable, Point dropPoint, Computer computer)  {
 Image image = Toolkit.getDefaultToolkit().getImage("images/" + imageName);
        Computer computer = simulator.createComputer();
                        GUIComputer guiComputer = new   GUIComputer(dropPoint.x, dropPoint.y, computer, image);
                         guiComputers.add(guiComputer);  
                         guiComputer.addObserver(this);

}

    @Override
     public void paintComponent(Graphics g) {

        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;      
            if (!GuiComputers.isEmpty()) {
                    for(GUIComputer guiComputer : guiComputers) {
                // redraw guiComputer
                            guiComputer.drawGuiComputer(g);
                        }
            }
}

    @Override
    public void update(Observable o, Object o1) {
    for(final GUIComputer guiComputer : guiComputers) {
                 if(guiComputer.getComputer().equals(o)) {  
                  //if update requested by Computer object then update gui, redrawing all guiComputers
                  revalidate();
                  repaint();
              }
    }
}
}

Answer 1

您可能会占用事件调度线程或EDT，但运行时间过长会占用事件线程上运行的一些代码：

public void simulate() {
    for(int step = 0; step < simulationSteps; step++) {
      for(Computer computer : computers) {
        computer.tick()
      }
    }
}

尝试使用SwingWorker或其他后台线程来解决此问题。

Answer 2

除非您在Thread.sleep()或tick()某处未显示simulate()，否则模拟应该立即运行。然后，所有对repaint（）的调用将合并为一个重绘。

修改

这是一个简单的例子，Observable线程上main()的零星更新显示在观察它们的GUI中：

import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.util.ArrayList; import java.util.List; import java.util.Observable; import java.util.Observer; import javax.swing.JFrame; import javax.swing.JPanel; public class Animation extends JPanel implements Observer { Simulation simulation; Animation(Simulation simulation) { this.simulation = simulation; setPreferredSize(new Dimension(200, 200)); for(Blob blob : simulation.blobs) { blob.addObserver(this); } } @Override public void update(Observable o, Object arg) { Blob blob = (Blob)o; repaint(blob.x - 12, blob.y - 12, 24, 24); } public void paintComponent(Graphics g) { super.paintComponent(g); for(Blob blob : simulation.blobs) { g.setColor(blob.color); g.fillOval(blob.x - 10, blob.y - 10, 20, 20); } } public static void main(String[] args) { Simulation simulation = new Simulation(); JFrame frame = new JFrame(); frame.getContentPane().add(new Animation(simulation)); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.pack(); frame.setVisible(true); simulation.simulate(); } } class Simulation { List<Blob> blobs = new ArrayList(); Simulation() { for(int i = 0; i < 20; ++i) { blobs.add(new Blob()); } } void simulate() { while(true) { try { Thread.sleep(50); } catch(InterruptedException e) { return; } for(Blob blob : blobs) { blob.tick(); } } } } class Blob extends Observable { int x = (int)(Math.random() * 180 + 10); int y = (int)(Math.random() * 180 + 10); float hue = (float)Math.random(); Color color = Color.getHSBColor(hue, 1, 1); void tick() { if(Math.random() < 0.05) { x += 4 * Math.random() - 2 + .5; y += 4 * Math.random() - 2 + .5; hue += Math.random() * .1 - .05; hue -= Math.floor(hue); color = Color.getHSBColor(hue, 1, 1); setChanged(); notifyObservers(); } } }

将java GUI更新为模型更改的内部状态

2 个答案: