visual basic 6.0 barcode generator 4: Creating a Download Manager in Java in Java

Generator PDF-417 2d barcode in Java 4: Creating a Download Manager in Java

4: Creating a Download Manager in Java
PDF417 Reader In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
PDF-417 2d Barcode Generation In Java
Using Barcode generation for Java Control to generate, create PDF-417 2d barcode image in Java applications.
URL verifiedUrl = null; try { verifiedUrl = new URL(url); } catch (Exception e) { return null; } // Make sure URL specifies a file. if (verifiedUrl.getFile().length() < 2) return null; return verifiedUrl; } // Called when table row selection changes. private void tableSelectionChanged() { /* Unregister from receiving notifications from the last selected download. */ if (selectedDownload != null) selectedDownload.deleteObserver(DownloadManager.this); /* If not in the middle of clearing a download, set the selected download and register to receive notifications from it. */ if (!clearing) { selectedDownload = tableModel.getDownload(table.getSelectedRow()); selectedDownload.addObserver(DownloadManager.this); updateButtons(); } } // Pause the selected download. private void actionPause() { selectedDownload.pause(); updateButtons(); } // Resume the selected download. private void actionResume() { selectedDownload.resume(); updateButtons(); } // Cancel the selected download.
Scanning PDF-417 2d Barcode In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
Barcode Generation In Java
Using Barcode creation for Java Control to generate, create barcode image in Java applications.
The Art of Java
Recognizing Bar Code In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
PDF 417 Generation In C#.NET
Using Barcode creation for VS .NET Control to generate, create PDF-417 2d barcode image in .NET framework applications.
private void actionCancel() { selectedDownload.cancel(); updateButtons(); } // Clear the selected download. private void actionClear() { clearing = true; tableModel.clearDownload(table.getSelectedRow()); clearing = false; selectedDownload = null; updateButtons(); } /* Update each button's state based off of the currently selected download's status. */ private void updateButtons() { if (selectedDownload != null) { int status = selectedDownload.getStatus(); switch (status) { case Download.DOWNLOADING: pauseButton.setEnabled(true); resumeButton.setEnabled(false); cancelButton.setEnabled(true); clearButton.setEnabled(false); break; case Download.PAUSED: pauseButton.setEnabled(false); resumeButton.setEnabled(true); cancelButton.setEnabled(true); clearButton.setEnabled(false); break; case Download.ERROR: pauseButton.setEnabled(false); resumeButton.setEnabled(true); cancelButton.setEnabled(false); clearButton.setEnabled(true); break; default: // COMPLETE or CANCELLED pauseButton.setEnabled(false); resumeButton.setEnabled(false); cancelButton.setEnabled(false); clearButton.setEnabled(true); } } else {
PDF417 Creator In .NET
Using Barcode creation for ASP.NET Control to generate, create PDF 417 image in ASP.NET applications.
PDF 417 Generator In .NET Framework
Using Barcode printer for Visual Studio .NET Control to generate, create PDF417 image in VS .NET applications.
4: Creating a Download Manager in Java
PDF 417 Creation In Visual Basic .NET
Using Barcode creation for VS .NET Control to generate, create PDF 417 image in VS .NET applications.
Draw ECC200 In Java
Using Barcode creator for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
// No download is selected in table. pauseButton.setEnabled(false); resumeButton.setEnabled(false); cancelButton.setEnabled(false); clearButton.setEnabled(false); } } /* Update is called when a Download notifies its observers of any changes. */ public void update(Observable o, Object arg) { // Update buttons if the selected download has changed. if (selectedDownload != null && selectedDownload.equals(o)) updateButtons(); } // Run the Download Manager. public static void main(String[] args) { DownloadManager manager = new DownloadManager(); manager.show(); } }
1D Drawer In Java
Using Barcode creation for Java Control to generate, create 1D Barcode image in Java applications.
Generate Bar Code In Java
Using Barcode printer for Java Control to generate, create barcode image in Java applications.
The DownloadManager Variables
Encode Standard 2 Of 5 In Java
Using Barcode creator for Java Control to generate, create Standard 2 of 5 image in Java applications.
Making Code39 In VS .NET
Using Barcode printer for VS .NET Control to generate, create Code 3/9 image in VS .NET applications.
DownloadManager starts off by declaring several instance variables, most of which hold references to the GUI controls. The selectedDownload variable holds a reference to the Download object represented by the selected row in the table. Finally, the clearing instance variable is a boolean flag that tracks whether or not a download is currently being cleared from the Downloads table.
Paint Bar Code In None
Using Barcode encoder for Office Excel Control to generate, create bar code image in Excel applications.
Read Bar Code In Visual C#.NET
Using Barcode Control SDK for .NET Control to generate, create, read, scan barcode image in .NET framework applications.
The DownloadManager Constructor
EAN13 Scanner In Visual Studio .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
Linear 1D Barcode Creation In C#
Using Barcode drawer for .NET Control to generate, create 1D Barcode image in VS .NET applications.
When the DownloadManager is instantiated, all of the GUI s controls are initialized inside its constructor. The constructor contains a lot of code, but most of it is straightforward. The following discussion gives an overview. First, the window s title is set with a call to setTitle( ). Next, the setSize( ) call establishes the window s width and height in pixels. After that, a window listener is added by calling addWindowListener( ), passing a WindowAdapter object that overrides the windowClosing( ) event handler. This handler calls the actionExit( ) method when the application s window is closed. Next, a menu bar with a File menu is added to the application s window. Then the Add panel, which has the Add Text field and button, is set up. An ActionListener is added to the Add Download button so that the actionAdd( ) method is called each time the button is clicked.
Drawing EAN / UCC - 13 In .NET Framework
Using Barcode generation for VS .NET Control to generate, create GS1 - 13 image in .NET applications.
Recognizing Code 128C In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
The Art of Java
The downloads table is constructed next. A ListSelectionListener is added to the table so that each time a row is selected in the table the tableSelectionChanged( ) method is invoked. The table s selection mode is also updated to ListSelectionModel.SINGLE_SELECTION so that only one row at a time can be selected in the table. Limiting row selection to only one row at a time simplifies the logic for determining which buttons should be enabled in the GUI when a row in the download table is selected. Next, a ProgressRenderer class is instantiated and registered with the table to handle the Progress column. The table s row height is updated to the ProgressRenderer s height by calling table.setRowHeight( ). After the table has been assembled and tweaked, it is wrapped in a JScrollPane to make it scrollable and then added to a panel. Finally, the buttons panel is created. The buttons panel has Pause, Resume, Cancel, and Clear buttons. Each of the buttons adds an ActionListener that invokes its respective action method when it is clicked. After creating the buttons panel, all of the panels that have been created are added to the window.
Copyright © OnBarcode.com . All rights reserved.