如何防止JInternalFrame重新绘制重叠JInternalFrame

Question

我有2个JInternalFrame每个都包含一个JPanel。一个JPanel（源代码）更新其GUI和一些响应鼠标事件的数据。另一个JPanel（目标）接收一个事件，指示数据已更改并相应地更新其外观。

如果源面板与目标面板重叠，则目标面板中的重新绘制会在源面板中触发重新绘制。同样，即使源面板遮挡了目标面板所需的更改，目标面板仍会重新绘制，并且仍会在源面板中触发重新绘制。

在我的现实生活应用程序中，这会产生性能问题，因为多个面板在鼠标拖动时会触发重新绘制，并且源面板会显示复杂的图像。

如何防止目标面板更新触发源面板中的重绘？

事情我已经尝试：

• 给参数重新粉刷这意味着只有目标面板的非重叠位重新刷新的问题，但对我来说，我不知道是哪个位的目标面板是可见的（我试过getVisibleRect和getClipBounds，但他们只是返回整个面板的大小）。在我的真实应用程序中，整个目标面板都会更新，而不仅仅是其中的一部分，所以我也不能以这种方式限制重新绘制。

• 基于现有的InternalFrameDemo创建了一个最小示例：同样的问题，请参阅下面的代码。该示例具有2个面板，如前所述，单击源面板（标记为Document 1）在该位置绘制红色框，并更新DataModel对象，该对象触发目标面板拾取的事件（标记为Document 2） ，它在本身的相同位置绘制一个红色框。在源paintComponent方法中设置断点，可以看到有2个更新，一个来自SourcePanel重绘，另一个来自TargetPanel重绘。

  public class InternalFrameDemo extends JFrame 
           implements ActionListener { 
  JDesktopPane desktop; 
  DataModel model = new DataModel(); 
  
  public InternalFrameDemo() { 
  super("InternalFrameDemo"); 
  
  //Make the big window be indented 50 pixels from each edge 
  //of the screen. 
  int inset = 50; 
  Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); 
  setBounds(inset, inset, 
        screenSize.width - inset*2, 
        screenSize.height - inset*2); 
  
  //Set up the GUI. 
  desktop = new JDesktopPane(); //a specialized layered pane 
  MyInternalFrame frame1 = createFrame(); //create first "window" 
  MyInternalFrame frame2 = createFrame(); 
  setContentPane(desktop); 
  
  SourcePanel sp = new SourcePanel(model); 
  frame1.add(sp); 
  TargetPanel tp = new TargetPanel(model); 
  frame2.add(tp); 
  
  //Make dragging a little faster but perhaps uglier. 
  desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE); 
  } 
  
  public void actionPerformed(ActionEvent e) { 
  } 
  
  //Create a new internal frame. 
  protected MyInternalFrame createFrame() { 
      MyInternalFrame frame = new MyInternalFrame(); 
      frame.setVisible(true); //necessary as of 1.3 
      frame.setOpaque(true); 
  
  
  desktop.add(frame); 
      try { 
       frame.setSelected(true); 
      } catch (java.beans.PropertyVetoException e) {} 
      return frame; 
  } 
  
  //Quit the application. 
  protected void quit() { 
      System.exit(0); 
  } 
  
  /** 
  * Create the GUI and show it. For thread safety, 
  * this method should be invoked from the 
  * event-dispatching thread. 
  */ 
  private static void createAndShowGUI() { 
      //Create and set up the window. 
      InternalFrameDemo frame = new InternalFrameDemo(); 
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
  
      //Display the window. 
      frame.setVisible(true); 
  } 
  
  public static void main(String[] args) { 
      //Schedule a job for the event-dispatching thread: 
      //creating and showing this application's GUI. 
      javax.swing.SwingUtilities.invokeLater(new Runnable() { 
       public void run() { 
        createAndShowGUI(); 
       } 
      }); 
  } 
  } 
  

---

package components; 

    import javax.swing.JInternalFrame; 

    /* Used by InternalFrameDemo.java. */ 
    public class MyInternalFrame extends JInternalFrame { 
    static int openFrameCount = 0; 
    static final int xOffset = 30, yOffset = 30; 

    public MyInternalFrame() { 
     super("Document #" + (++openFrameCount), 
       true, //resizable 
       true, //closable 
       true, //maximizable 
       true);//iconifiable 

     setSize(300,300); 
     setLocation(xOffset*openFrameCount, yOffset*openFrameCount); 
    } 
} 

---

package components; 

import java.awt.Color; 
import java.awt.Graphics; 
import java.awt.event.MouseAdapter; 
import java.awt.event.MouseEvent; 

import javax.swing.JPanel; 
import javax.swing.SwingUtilities; 

public class SourcePanel extends JPanel { 

    int boxX, boxY; 
    int boxWidth = 10; 
    int boxHeight = 10; 

    public SourcePanel(DataModel data) { 

     addMouseListener(new MouseAdapter() 
     { 
      @Override 
      public void mousePressed(MouseEvent evt) 
      { 
      if (!SwingUtilities.isRightMouseButton(evt)) 
      { 
       boxX = evt.getX(); 
       boxY = evt.getY(); 
       data.update(boxX,boxY); 
       repaint(); 
      } 
      } 
     }); 
    } 

    @Override 
    public void paintComponent(Graphics g) 
    { 
     super.paintComponent(g); 
     g.setColor(Color.RED); 
     int x = Math.min(boxX, this.getWidth()-boxWidth); 
     int y = Math.min(boxY, this.getHeight()-boxHeight); 
     g.drawRect(x, y, boxWidth, boxHeight); 
     g.drawRect(x + 1, y + 1, boxWidth - 2, boxHeight - 2); 
    } 
} 

---

package components; 

import java.awt.Color; 
import java.awt.Graphics; 
import java.beans.PropertyChangeEvent; 
import java.beans.PropertyChangeListener; 

import javax.swing.JPanel; 

public class TargetPanel extends JPanel implements PropertyChangeListener { 

    int boxX, boxY; 
    int boxWidth = 10; 
    int boxHeight = 10; 

    public TargetPanel(DataModel data) { 
     data.addPropertyChangeListener(this); 
    } 

    @Override 
    public void propertyChange(PropertyChangeEvent evt) 
    { 
     //draw something in response to the data change 
     boxX = ((int[])evt.getNewValue())[0]; 
     boxY = ((int[])evt.getNewValue())[1]; 
     repaint(); 
    } 

    @Override 
    public void paintComponent(Graphics g) 
    { 
     super.paintComponent(g); 
     g.setColor(Color.BLUE); 
     g.fillRect(0, 0, getWidth(), getHeight()); 
     g.setColor(Color.RED); 
     int x = Math.min(boxX, this.getWidth()-boxWidth); 
     int y = Math.min(boxY, this.getHeight()-boxHeight); 
     g.fillRect(x, y, boxWidth, boxHeight); 
    } 
} 

---

package components; 

import java.beans.PropertyChangeListener; 
import java.beans.PropertyChangeSupport; 

public class DataModel { 

    int datax = 10; 
    int datay = 10; 

    public DataModel() 
    { 
    } 

    public void update(int x, int y) 
    { 
     int[] olddata = new int[]{datax,datay}; 
     datax = x; 
     datay = y; 
     int[] newdata = new int[]{datax,datay}; 
     changeSupport.firePropertyChange("DataChange", olddata, newdata); 
    } 

    protected PropertyChangeSupport changeSupport = new PropertyChangeSupport(
       this); 

    public void addPropertyChangeListener(PropertyChangeListener listener) 
    { 
     changeSupport.addPropertyChangeListener(listener); 
    } 

    public void removePropertyChangeListener(PropertyChangeListener listener) 
    { 
     changeSupport.removePropertyChangeListener(listener); 
    } 

} 

（版权声明原始JInternalFrame的示例代码:)

/* 
* Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved. 
* 
* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions 
* are met: 
* 
* - Redistributions of source code must retain the above copyright 
*  notice, this list of conditions and the following disclaimer. 
* 
* - Redistributions in binary form must reproduce the above copyright 
*  notice, this list of conditions and the following disclaimer in the 
*  documentation and/or other materials provided with the distribution. 
* 
* - Neither the name of Oracle or the names of its 
*  contributors may be used to endorse or promote products derived 
*  from this software without specific prior written permission. 
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
*/ 

Answer 1

您可以缓存鼠标变化，做他们的时间间隔，或在鼠标跟踪结束。

最容易的可能是尝试推迟重画。

@Override 
public void propertyChange(PropertyChangeEvent evt) 
{ 
    //draw something in response to the data change 
    boxX = ((int[])evt.getNewValue())[0]; 
    boxY = ((int[])evt.getNewValue())[1]; 
    repaint(200L); 
} 

实际上重绘几次后，呼吁repaint(200L);。 （对于我的感觉，我选择了第五秒的高值）。