Create BackgroundbuttonWidget and restore ButtonWidget

demo/config/targets/INST/screens/commanding.txt

@@ -14,6 +14,8 @@ VERTICAL
       NAMED_WIDGET COLLECT_TYPE COMBOBOX NORMAL SPECIAL
       LABEL "  Duration: "
       NAMED_WIDGET DURATION TEXTFIELD 12 "10.0"
+      # Button widgets execute their code directly in the GUI thread
+      # This allows us to directly ask for the text on the named widget
       BUTTON 'Start Collect' 'target_name = get_target_name("INST"); cmd("#{target_name} COLLECT with TYPE #{get_named_widget("COLLECT_TYPE").text}, DURATION #{get_named_widget("DURATION").text.to_f}")'
     END
   END
@@ -31,7 +33,10 @@ VERTICAL
   VERTICALBOX
     SECTIONHEADER "Run Script:"
     NAMED_WIDGET SCRIPTNAME COMBOBOX <%= Dir["#{Cosmos::System.paths['PROCEDURES'][0]}/*"].map {|x| File.basename(x) }.join(' ') %>
-    BUTTON 'Run Script' 'Cosmos.run_process("#{Cosmos::USERPATH}/tools/ScriptRunner -r #{get_named_widget("SCRIPTNAME").text}")'
+    # Here as an example we're using the BACKGROUNDBUTTON which runs all the code in the background.
+    # Note we didn't need to use this here but it's an example of wrapping calls to the GUI in Qt.execute_in_main_thread.
+    # You need to use this button if your code blocks or takes a long time to execute so you don't hang the screen.
+    BACKGROUNDBUTTON 'Run Script' 'Cosmos.run_process("#{Cosmos::USERPATH}/tools/ScriptRunner -r #{Qt.execute_in_main_thread { get_named_widget("SCRIPTNAME").text }}")'
   END
   SETTING BACKCOLOR 163 185 163
 END

lib/cosmos/tools/tlm_viewer/widgets.rb

@@ -2,6 +2,7 @@
 require 'cosmos/tools/tlm_viewer/widgets/array_widget.rb'
 require 'cosmos/tools/tlm_viewer/widgets/block_widget.rb'
 require 'cosmos/tools/tlm_viewer/widgets/button_widget.rb'
+require 'cosmos/tools/tlm_viewer/widgets/backgroundbutton_widget.rb'
 require 'cosmos/tools/tlm_viewer/widgets/canvasdot_widget.rb'
 require 'cosmos/tools/tlm_viewer/widgets/canvasimagevalue_widget.rb'
 require 'cosmos/tools/tlm_viewer/widgets/canvasimage_widget.rb'

lib/cosmos/tools/tlm_viewer/widgets/backgroundbutton_widget.rb

@@ -0,0 +1,54 @@
+# encoding: ascii-8bit
+
+# Copyright 2014 Ball Aerospace & Technologies Corp.
+# All Rights Reserved.
+#
+# This program is free software; you can modify and/or redistribute it
+# under the terms of the GNU General Public License
+# as published by the Free Software Foundation; version 3 with
+# attribution addendums as found in the LICENSE.txt
+
+# This file contains the implementation of the BackgroundbuttonWidget class.
+
+require 'cosmos'
+require 'cosmos/tools/tlm_viewer/widgets/widget'
+require 'cosmos/gui/utilities/script_module_gui'
+
+module Cosmos
+  # Run user defined code in the background. This means that all code which
+  # interacts with the GUI MUST be wrapped in Qt.execute_in_main_thread.
+  class BackgroundbuttonWidget < Qt::PushButton
+    include Widget
+
+    def initialize(parent_layout, button_text, string_to_eval)
+      super()
+      setText(button_text.to_s)
+      connect(SIGNAL('clicked()')) { execute(string_to_eval.to_s) }
+      parent_layout.addWidget(self) if parent_layout
+    end
+
+    def execute(code)
+      # Disable the button while the code is executed to avoid thrashing
+      setEnabled(false)
+      # Spawn a new thread to avoid blocking the GUI.
+      Thread.new do
+        begin
+          @screen.instance_eval(code)
+        rescue DRb::DRbConnError
+          Qt.execute_in_main_thread do
+            Qt::MessageBox.warning(parent.parentWidget, 'Error', "Error Connecting to Command and Telemetry Server")
+          end
+        rescue Exception => error
+          message = error.message
+          if error.message.include?("Qt methods cannot be called")
+            message = "Error executing button code:\n#{code}\n\nYou must wrap calls to the GUI in Qt.execute_in_main_thread { <GUI Code> }"
+          end
+          Qt.execute_in_main_thread do
+            Qt::MessageBox.warning(parent.parentWidget, 'Error', "#{error.class} : #{message}")
+          end
+        end
+        Qt.execute_in_main_thread { self.setEnabled(true) }
+      end
+    end
+  end
+end

lib/cosmos/tools/tlm_viewer/widgets/button_widget.rb

@@ -15,39 +15,25 @@
 require 'cosmos/gui/utilities/script_module_gui'
 
 module Cosmos
+  # Run user defined code in the GUI thread context. This means that user
+  # code should not block or take too long to execute as it will freeze
+  # the TlmViewer screen.
   class ButtonWidget < Qt::PushButton
     include Widget
 
     def initialize(parent_layout, button_text, string_to_eval)
       super()
       setText(button_text.to_s)
-      connect(SIGNAL('clicked()')) { execute(string_to_eval.to_s) }
-      parent_layout.addWidget(self) if parent_layout
-    end
-
-    def execute(code)
-      # Disable the button while the code is executed to avoid thrashing
-      setEnabled(false)
-      # Spawn a new thread to avoid blocking the GUI. Users will have to
-      # wrap any GUI interaction in Qt.execute_in_main_thread.
-      Thread.new do
+      connect(SIGNAL('clicked()')) do
         begin
-          @screen.instance_eval(code)
+          @screen.instance_eval(string_to_eval.to_s)
         rescue DRb::DRbConnError
-          Qt.execute_in_main_thread do
-            Qt::MessageBox.warning(parent.parentWidget, 'Error', "Error Connecting to Command and Telemetry Server")
-          end
+          Qt::MessageBox.warning(parent.parentWidget, 'Error', "Error Connecting to Command and Telemetry Server")
         rescue Exception => error
-          message = error.message
-          if error.message.include?("Qt methods cannot be called")
-            message = "Error executing button code:\n#{code}"
-          end
-          Qt.execute_in_main_thread do
-            Qt::MessageBox.warning(parent.parentWidget, 'Error', "#{error.class} : #{message}")
-          end
+          Qt::MessageBox.warning(parent.parentWidget, 'Error', "#{error.class} : #{error.message}")
         end
-        Qt.execute_in_main_thread { self.setEnabled(true) }
       end
+      parent_layout.addWidget(self) if parent_layout
     end
   end
 end