When we save our project in Qt Designer, it will create a.ui file, which is just XML containing all the properties (widgets, sizes, signals & slots, etc.) that make up the GUI. PyQt comes with a program, pyuic4, that can convert these.ui files to Python code. It is our Pyqt5 Slots And Signals priority to provide players with an entertainment site that follows the international gaming standards. Social responsibility and player’s protection remain as our prime concern. 88ProBet strives to provide a comfortable and responsible gaming environment by offering assistance to players in need. An introduction to creating PySide/PyQt signals and slots, using QObject. How signals and slots are useful, and what they can do when developing in PySide/PyQt.

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This section describes the older style for connecting signals and slots. Ituses the same API that a C++ application would use. This has a number ofadvantages.

• It is well understood and documented.
• Any future changes to the C++ API should be easily included.

It also has a number of disadvantages.

• It requires knowledge of the C++ types of signal arguments.
• It is error prone in that if you mis-type the signal name or signature thenno exception is raised, either when the signal is connected or emitted.
• It is verbose.
• It is not Pythonic.

This older style of connecting signals and slots will continue to be supportedthroughout the life of PyQt4.

PyQt4 Signals and Qt Signals¶

Qt signals are statically defined as part of a C++ class. They are referencedusing the QtCore.SIGNAL() function. This method takes a single stringargument that is the name of the signal and its C++ signature. For example:

The returned value is normally passed to the QtCore.QObject.connect()method.

PyQt4 allows new signals to be defined dynamically. The act of emitting aPyQt4 signal implicitly defines it. PyQt4 signals are also referenced usingthe QtCore.SIGNAL() function.

The PyQt_PyObject Signal Argument Type¶

It is possible to pass any Python object as a signal argument by specifyingPyQt_PyObject as the type of the argument in the signature. For example:

While this would normally be used for passing objects like lists anddictionaries as signal arguments, it can be used for any Python type. Itsadvantage when passing, for example, an integer is that the normal conversionsfrom a Python object to a C++ integer and back again are not required.

The reference count of the object being passed is maintained automatically.There is no need for the emitter of a signal to keep a reference to the objectafter the call to QtCore.QObject.emit(), even if a connection is queued.

Short-circuit Signals¶

There is also a special form of a PyQt4 signal known as a short-circuit signal.Short-circut signals implicitly declare each argument as being of typePyQt_PyObject.

Short-circuit signals do not have a list of arguments or the surroundingparentheses.

Short-circuit signals may only be connected to slots that have been implementedin Python. They cannot be connected to Qt slots or the Python callables thatwrap Qt slots.

PyQt4 Slots and Qt Slots¶

Qt slots are statically defined as part of a C++ class. They are referencedusing the QtCore.SLOT() function. This method takes a single stringargument that is the name of the slot and its C++ signature. For example:

The returned value is normally passed to the QtCore.QObject.connect()method.

PyQt4 allows any Python callable to be used as a slot, not just Qt slots. Thisis done by simply referencing the callable. Because Qt slots are implementedas class methods they are also available as Python callables. Therefore it isnot usually necessary to use QtCore.SLOT() for Qt slots. However, doing sois more efficient as it avoids a conversion to Python and back to C++.

Qt allows a signal to be connected to a slot that requires fewer arguments thanthe signal passes. The extra arguments are quietly discarded. PyQt4 slots canbe used in the same way.

Note that when a slot is a Python callable its reference count is notincreased. This means that a class instance can be deleted without having toexplicitly disconnect any signals connected to its methods. However, if a slotis a lambda function or a partial function then its reference count isautomatically incremented to prevent it from being immediately garbagecollected.

Connecting Signals and Slots¶

Connections between signals and slots (and other signals) are made using theQtCore.QObject.connect() method. For example:

Disconnecting signals works in exactly the same way using theQtCore.QObject.disconnect() method. However, not all the variations ofthat method are supported by PyQt4. Signals must be disconnected one at atime.

Emitting Signals¶

Any instance of a class that is derived from the QtCore.QObject class canemit a signal using its emit() method. This takes a minimum of oneargument which is the signal. Any other arguments are passed to the connectedslots as the signal arguments. For example:

The QtCore.pyqtSignature() Decorator¶

The QtCore.pyqtSignature() serves the same purpose as thepyqtSlot() decorator but has a less Pythonic API.

Design multiple windows in designer

To jump, of course, there must be multiple windows, so we design another window in designer. When we click the login button in the main interface, we will jump to this window.
The method is the same. Drag the control, save it as a. ui file after it is designed, and then convert the. ui file to a. py file.

They are connected by signals and slots

What are signals, slots?
This is a feature of designer. The user will send a signal to guide the slot function to complete the corresponding action. Too abstract, for example.
The code for the main window looks like this.

The above statement to complete the window jump is as follows.

signal

Slot function

So to complete the jump, we have to go through the following steps:

1. Add signals and slots

On the control where you want to add a signal, add a statement. For example, we add a signal to the login button with the object name as the pushButton to connect to the open() slot function, which is used to open a new window.

• self: for UI_ Instantiation object of MainWindow
• pushbutton: the object name of the login button
• Click: signal means to send the signal to the slot function when the user clicks the login button
• Slot and signal connection functions: connect
• open: slot function, that is, after receiving the signal, the function is called.

• Import: is the name of the new window, tiaozhuan.py .
  In addition, when opening a new window, we need to close the original login window. In the same way, add a signal on the login button.

signal

Slot function

It is important to note that the close() method must be called with the real instantiated object when closing the window. It can't be replaced by self.

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2. Modify the called window

Two modifications are needed:

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• class Ui_MainWindow(QMainWindow): change the object to QMainWindow

• def __init__(self): ා add initialization function super (UI)_ MainWindow,self).__ init__ () self.setupUi (self)

  Add initialization function to class

3. Run the main window
Directly run the main window, you can see the heart of the GUI!

Note: in this case, if you want to run the program, you have to add a file.
Because in the tiaozhuan.py In this window, we introduce three pictures. How to solve this problem, put the resource file in the tiaozhuan.py File in the same directory.
Resource file code link: (put a piece of words, the article is too long to send out... )
https://download.csdn.net/download/leidawangzi/13613277

How to get the resource file? Moving on to the next section, we'll learn how to add pictures to the control.

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Bibliography: Python GUI design (PyQt5 from introduction to practice) - tomorrow Technology