如何每秒鐘更新容器小部件中的標籤小部件

Question

因此，我有一個包含小部件的GUI，它在數據庫中查找變量的值，並以與kv對相同的方式顯示變量名稱和當前值兩個QLabel彼此相鄰，並稱他們爲DisplayItemWidget。然後，我在另一個窗口小部件中堆疊了一堆這些DisplayItemWidget，我稱其爲CellContainerWidget，並且我在網格中有一堆這樣的小部件，這樣我可以在變化時跟蹤多個變量分組。所有小部件查詢的數據庫都在不斷更新，我希望我的GUI能夠更新每個人的更新，每秒鐘更新一次。但我不知道該怎麼做。我嘗試使用QTimer將定時器事件發送到MainWindow，但這不起作用。所以我想知道什麼是體系結構應該是每秒更新內部小部件。

我的代碼的一個精簡版是在這裏：

from PyQt4.QtGui import * 
    from PyQt4.QtCore import * 
    import sys 
    import random 

    def main(): 
     app = QApplication(sys.argv) 
     db = Database() 

     ########## instantiate fake data 
     cell_list = [] 
     taglist = ['ground_tlm', 'state_tlm'] 
     counter = 0 
     for tag in taglist: 
      display_list = [] 
      display_name = tag.split('_')[0] + ' stuff' 
      for i in range(int((random.random()*5)+1)): 
       db.update([tag, 'var-%i' % i, 'float', str(random.random())]) 
       widget = DisplayItemWidget(tag, 'var-%i' % i, db) 
       display_list.append(widget) 
      ccw = CellContainerWidget(display_list, display_name, counter, 0) 
      counter += 1 
      cell_list.append(ccw) 

     taglist = ['random_tlm', 'up_tlm'] 
     counter = 0 
     for tag in taglist: 
      display_list = [] 
      display_name = tag.split('_')[0] + ' stuff' 
      for i in range(int((random.random()*5)+1)): 
       db.update([tag, 'var-%i' % i, 'float', str(random.random())]) 
       widget = DisplayItemWidget(tag, 'var-%i' % i, db) 
       display_list.append(widget) 
      ccw = CellContainerWidget(display_list, display_name, counter, 1) 
      counter += 1 
      cell_list.append(ccw) 
     ########## 

     mw = MainWindow(cell_list, db) 
     mw.show() 
     timer = QBasicTimer() 
     timer.start(500, mw) 
     sys.exit(app.exec_()) 


    class DisplayItemWidget(QWidget): 

     def __init__(self, tag, var_name, db): 
      super(DisplayItemWidget, self).__init__() 
      self.layout = QHBoxLayout() 
      self.label1 = QLabel() 
      self.label2 = QLabel() 
      self.tag = tag 
      self.var_name = var_name 
      self.db = db 
      self.init_ui() 

     def init_ui(self): 
      self.label1.setText(self.tag + ': ' + self.var_name) 

      self.label1.setAlignment(Qt.AlignCenter) 
      self.label1.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.MinimumExpanding) 
      self.layout.addWidget(self.label1) 

      val = self.db.get_val(self.tag, self.var_name) 
      if val is not None: 
       self.label2.setText(val) 
       self.label2.setText(val) 
      self.label2.setAlignment(Qt.AlignCenter) 
      self.label2.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.MinimumExpanding) 
      self.layout.addWidget(self.label2) 

      self.layout.setSpacing(10) 
      self.setLayout(self.layout) 
      self.setWindowTitle("Display Item Widget") 

     def update_value(self): 
      val = self.db.get_val(self.tag, self.var_name) 
      if val is not None: 
       self.label2.setText(val) 


    class CellContainerWidget(QWidget): 

     def __init__(self, display_list, cell_name, col_index, row_index): 
      super(CellContainerWidget, self).__init__() 
      self.layout = QVBoxLayout() 
      self.cell_name_label = QLabel() 
      self.cell_name_label.setText(cell_name) 
      self.display_list = display_list 
      self.col_index = col_index 
      self.row_index = row_index 
      self.init_ui() 

     def init_ui(self): 
      self.cell_name_label.setAlignment(Qt.AlignCenter) 
      self.cell_name_label.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed) 
      self.layout.addWidget(self.cell_name_label) 

      for widget in self.display_list: 
       widget.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.MinimumExpanding) 
       self.layout.addWidget(widget) 

      self.layout.setSpacing(0) 
      self.setLayout(self.layout) 
      self.setWindowTitle("Cell Item Widget") 

     def get_widgets(self): 
      return self.display_list 


    class MainWindow(QWidget): 
     def __init__(self, cell_list, db): 
      super(MainWindow, self).__init__() 
      self.layout = QGridLayout() 
      self.cell_list = cell_list 
      self.db = db 
      self.init_ui() 

     def init_ui(self): 
      for cell in self.cell_list: 
       cell.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.MinimumExpanding) 
       self.layout.addWidget(cell, cell.col_index, cell.row_index) 

      self.layout.setSpacing(0) 
      self.setLayout(self.layout) 
      self.setWindowTitle("Main Window Widget") 

     def update_gui(self, event): 

      ########## Mock out update to first column 
      print self.db.print_contents() 
      taglist = ['ground_tlm', 'state_tlm'] 
      for tag in taglist: 
       for i in range(int((random.random()*5)+1)): 
        self.db.update([tag, 'var-%i' % i, 'float', str(random.random())]) 
      ########## 

      for cell in self.cell_list: 
       for widget in cell.get_widgets(): 
        widget.update_value() 


    class Database(): 
     def __init__(self): 
      self.telemetry_types = { 
       'state_tlm': {'var-1': ('int', '0'), } # Example of how this will be populated 
      } 

     def get_var_table(self, tlm_type): 
      return self.telemetry_types.get(tlm_type, None) 

     def update(self, parsed_data): 
      tlm_type, var_name, var_type, datum = parsed_data 
      if tlm_type in self.telemetry_types: 
        self.telemetry_types[tlm_type][var_name] = (var_type, datum) 
      else: 
       self.telemetry_types[tlm_type] = { 
        var_name: (var_type, datum), 
       } 

     def get_val(self, tlm_type, var_name): 
      if tlm_type in self.telemetry_types: 
       if var_name in self.telemetry_types[tlm_type]: 
        return self.telemetry_types[tlm_type][var_name][1] 
       else: 
        return None 
      else: 
       return None 

     def print_contents(self): 
      print self.telemetry_types 

     def get_keys(self): 
      return self.telemetry_types.keys() 

    if __name__ == '__main__': 
     main() 

只更新一次，然後永不復還。事件計時器甚至沒有被mw註冊。我覺得我錯失了一些根本性的錯誤。

Answer 1

您沒有正確實例化您的計時器。

當前，您將對象mw傳遞給QBasicTimer，但該對象尚未寫入來處理Timer事件。總之，它不知道它應該調用update_gui（爲什麼不是嗎？這是你創建的任意命名的方法！）

相反，我會建議構建一個計時器，如下所示，使用QTimer類，而比QBasicTimer：

timer = QTimer(mw) 
timer.timeout.connect(mw.update_gui) 
timer.start(500) 

這就產生了一個QTimer，連接timeout信號到update_gui槽並啓動定時器（以500毫秒的超時）。

請注意，您還需要將MainWindow.update_gui的簽名更改爲不包含event變量。所以它應該看起來像def update_gui(self):