When you provide exact coordinates for your widget’s position, the technique that you used is called absolute positioning. To prevent the widgets from overlapping, you need to set the y-coordinate to 55 for the button’s position. Then you add your button to the panel and give it a label. So for the text control, you tell wxPython that you want to position its top left corner 5 pixels from the left (x) and 5 pixels from the top (y). In wxPython, the origin location is (0,0) which is the upper left corner of the parent. You also need to tell wxPython where to place the widget, which you can do by passing in a position via the pos parameter. In this case, you want the text control and the button to be on top of the panel, so it is the parent you specify. The first argument for almost all widgets is which parent the widget should go onto. The next step is to add a wx.TextCtrl to the panel. When you add the panel widget to a frame and the panel is the sole child of the frame, it will automatically expand to fill the frame with itself. Tab traversal is disabled without a Panel on Windows. On Windows, you are actually required to use a Panel so that the background color of the frame is the right shade of gray. This widget is not required, but recommended. The first widget you need to add is something called wx.Panel. When you run this code, your application should look like this: ![]() Button ( panel, label = 'Press Me', pos = ( 5, 55 )) self. TextCtrl ( panel, pos = ( 5, 5 )) my_btn = wx. _init_ ( parent = None, title = 'Hello World' ) panel = wx. Let’s create a skeleton application to demonstrate how events work. The wxPython framework has special thread-safe methods that you can use to communicate back to your application to let it know that the thread is finished or to give it an update. This will prevent your GUI from freezing and give the user a better user experience. When you block an event loop, the GUI will become unresponsive and appear to freeze to the user.Īny process that you launch in a GUI that will take longer than a quarter second should probably be launched as a separate thread or process. There is a special consideration that you need to keep in mind when working with event loops: they can be blocked. When you are programming a graphical user interface, you will want to keep in mind that you will need to hook up each of the widgets to event handlers so that your application will do something. When the application doesn’t catch an event, it effectively ignores that it even happened. The event loop just waits for events to occur and then acts on those events according to what the developer has coded the application to do. Underneath the covers, the GUI toolkit is running an infinite loop that is called an event loop. Events happen when the user types something while your application is in focus or when the user uses their mouse to press a button or other widget. Event LoopsĪ graphical user interface works by waiting for the user to do something. A developer will take the widgets and arrange them logically on a window for the user to interact with. There are many other common widgets and many custom widgets that wxPython supports. User interfaces have some common components:Īll of these items are known generically as widgets. Definition of a GUIĪs was mentioned in the introduction, a graphical user interface (GUI) is an interface that is drawn on the screen for the user to interact with. ![]() You can even edit and re-run the code in the demo to see how your changes affect the application.īe sure you have modified the command above to match your version of Linux. The demo allows a developer to view the code in one tab and run it in a second tab. This is a nice little application that demonstrates the vast majority of the widgets that are included with wxPython. Here, there is a download of the wxPython Demo package. The wxPython downloads page has a section called Extra Files that is worth checking out. ![]() In fact, the wxPython toolkit has many custom widgets included with it, along with dozens upon dozens of core widgets. This is not to say that wxPython does not support custom widgets. ![]() PyQt and Tkinter both draw their widgets themselves, which is why they don’t always match the native widgets, although PyQt is very close. This makes wxPython applications look native to the operating system that it is running on. wxPython’s primary difference from other toolkits, such as PyQt or Tkinter, is that wxPython uses the actual widgets on the native platform whenever possible. The initial release of wxPython was in 1998, so wxPython has been around quite a long time. The wxPython GUI toolkit is a Python wrapper around a C++ library called wxWidgets. Free Download: Get a sample chapter from Python Tricks: The Book that shows you Python’s best practices with simple examples you can apply instantly to write more beautiful + Pythonic code.
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