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POrepaint() fails to work
 

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    <p>I wanted to draw an image on my panel based on the data I receive from another thread. I am sure the data and consequent pixel array works well, but the repaint() would never work. Can anyone tell me what's going wrong here?</p> <pre><code>import javax.swing.*; import java.awt.*; import java.awt.image.*; /** Create an image from a pixel array. **/ public class PicturePlaza extends JApplet { ImagePanel fImagePanel; ReadCom readComPort; Thread readPortThread; public void init () { // initiate the read port thread so that it can receive data readComPort = new ReadCom(); readPortThread = new Thread(readComPort,"ReadCom"); readPortThread.start(); Container content_pane = getContentPane (); fImagePanel = new ImagePanel (); content_pane.add (fImagePanel); } // Tell the panel to create and display the image, if pixel data is ready. public void start () { while(true){ if(readComPort.newPic){ fImagePanel.go(); } try { Thread.sleep(4000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } /** Create an image from a pixel array. **/ class ImagePanel extends JPanel{ Image fImage; int fWidth = ReadCom.row, fHeight = ReadCom.col; void go() { //update the image if newPic flag is set to true fImage = createImage (new MemoryImageSource (fWidth, fHeight, ReadCom.fpixel, 0, fWidth)); repaint(); readComPort.newPic = false; //disable the flag, indicating the image pixel has been used } /** Paint the image on the panel. **/ public void paintComponent (Graphics g) { super.paintComponent (g); g.drawImage (fImage, 0, 0, this ); } } } </code></pre> <p>Thanks</p>
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    1. USAdam Houldsworth
    1. USDaniel
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    1. CO`Thread.sleep(4000);` Don't block the EDT (Event Dispatch Thread) - the GUI will 'freeze' when that happens. Instead of calling `Thread.sleep(n)` implement a Swing `Timer` for repeating tasks or a `SwingWorker` for long running tasks. See [Concurrency in Swing](http://docs.oracle.com/javase/tutorial/uiswing/concurrency/) for more details.
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      1. USAndrew Thompson
    2. COThanks for your instant response. But if I simply remove the statement Thread.sleep(4000), it fails to work as well. What is the reason for that?
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      1. USDaniel
    3. COIf you simply read the links I provided, and implement the recommendations, what happens?
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