Programming the Be Operating System-Chapter 9: Messages and Threads

... looper and a handler). Throughout this chapter you’ll see sev- eral examples of the creating of messages and the dispatching of these messages both by the object that created them and by other ... message and the target of the message don’t have to be one and the same, they can be as shown in this snippet (read the Application-Defined Messages 357 identical to...

Ngày tải lên: 17/10/2013, 19:15

... altered—as they are here with the writing of the string “Quitting ” the view needs to be updated before the changes become visible onscreen. If the changes are made while the view’s window is hidden, then ... chapter. The beep() global function plays the system beep. Sound (and thus the beep() function) is a topic covered in the Media Kit chapter of the Be Book. View...

Ngày tải lên: 26/01/2014, 07:20

... *buttonBeep1Name = "Beep1"; const char *buttonBeep2Name = "Beep2"; const char *buttonBeep1Label = "Beep One"; const char *buttonBeep2Label = "Beep Two"; In the ... immediately change the setting. Instead, when the user dismisses the window the checkbox resides in, the value of the checkbox can be queried and the setting of the prog...

Ngày tải lên: 26/01/2014, 07:20

... the upcoming file saving and opening changes. While looking over the old code, I’ll insert a few changes here and there to ready the program for the file-handling code. The changes begin in the ... MyDrawView under the menubar, there’s no need to resize the frame such that it fills the window, less the menubar area. The MyHelloWindow constructor next establishes the...

Ngày tải lên: 20/10/2013, 10:15

... dis- patches messages, and a BHandler object receives and handles these dispatched messages. Because the BLooper class is derived from the BHandler class, a BLooper object can dispatch and receive and handle ... dispatches messages and can receive these messages itself for handling. Because the BApplication class and the BWindow class are derived from the BLooper c...

Ngày tải lên: 26/01/2014, 07:20

... will be beneficial as you look at existing BeIDE example projects and as you then start to write your own BeOS program. The BeIDE Folders When the BeIDE is installed on your hard drive, the folders ... name, enter the name to change in the Find box, enter the new name in the Replace box, and click the Replace All button. The BeIDE will search all the project files fo...

Ngày tải lên: 26/01/2014, 07:20

... value comes from a Be- defined constant. In such cases the Be- defined constants will be listed and described in the Constructor and Destructor section. For example, the third of the BWindow constructor’s ... explicitly call the object’s destructor when being destroyed. That’s because the BeOS does the work. The Constructor and Destructor section lets you know when t...

Ngày tải lên: 26/01/2014, 07:20

... 10.0); The call to MovePenTo() moves the pen to the location 30 pixels from the left of the view and 40 pixels from the top of the view. That places the pen at the point (30.0, 40.0). The call ... of the pixels in the rectangle are purple. Instead, each is either red or blue. Because the pixels alternate between these two colors, and because pixel density is high...

Ngày tải lên: 26/01/2014, 07:20

... to determine the item’s current label before changing it to a new string. The type of label-changing shown in the above snippet is a good candidate for the use of both Label() and SetLabel(). If the user ... the menubar and add it to the win- dow, create the menu and add it to the menubar, and create the menu item and add it to the menu. The menu-related code...

Ngày tải lên: 26/01/2014, 07:20

... recognizes and reacts to is the standard message. A standard mes- sage is known to the system, and may be issued by the system, but it doesn’t have a hook function. Among the many standard messages the ... typed into the text view object will have 20 pixels of white space between the object’s left edge and the character and 20 pixels of white space between the ob...

Ngày tải lên: 26/01/2014, 07:20