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--- qt:wiring_up_signals_and_slots [2011/03/31 13:00] – [Do it in the *.ui file] mithat
+++ qt:wiring_up_signals_and_slots [2011/04/01 11:13] – [Creating signal→slot connections] mithat
@@ Line 2: / Line 2: @@
 ===== Creating signal→slot connections =====
-Qt uses a signals and slots system to process events. If you use Qt Creator for development, there are at least four different ways to make signal->slot connections:
+Qt uses a [[signals and slots]] system to process events. If you use Qt Creator for development, there are at least four different ways to make signal->slot connections:
-  * Create an "event handler"
+  * [[#Create an "event handler"]]
-  * Do it "visually"
+  * [[#Do it "visually"]]
-  * Do it in the *.ui file
+  * [[#Do it in the *.ui file]]
-  * Do it in the constructor
+  * [[#Do it in the constructor ]]
 If you use Qt Designer with some other IDE for development, three of these are available to you. If you are hand-coding everything, then two are. Each of the above listed approaches are discussed below.
@@ Line 16: / Line 16: @@
 A handler you make this way for a ''button_quit'' widget might look like:
-<code cpp>
+<code cpp-qt>
 void MainWindow::on_button_quit_clicked()
 {
@@ Line 23: / Line 23: @@
 The handlers you create this way are actually a private slots. You can confirm this by looking at the header file for the class you are editing:
-<code cpp>
+<code cpp-qt>
 private slots:
     void on_button_quit_clicked();</code>
 === Behind the scenes ===
-How does the build system know that that ''button_quit'''s ''clicked()'' signal connects to ''MainWindow'''s ''on_button_quit_event_clicked()'' slot? It appears that the connection between signals and slots created this way is done purely via a naming convention along the following lines: ''//<widget-name>//'' ''//<signal>()//'' automatically connects to any slot of the form ''//<ClassName>//::on_//<widget-name>_<signal>()//''.
+How does the build system know that that ''button_quit'''s ''clicked()'' signal connects to ''MainWindow'''s ''on_button_quit_event_clicked()'' slot? It appears that the connection between signals and slots created this way is done purely via a naming convention along the following lines:
+<code cpp-qt><widget-name> <signal-name>()</code> automatically connects to any slot of the form <code cpp-qt><ClassName>::on_<widget-name>_<signal-name>()</code>
+== Question ==
+If the above is true, then it should be possible to create event handlers just by writing code. Two tests are indicated:
+  * Write the handlers manually in Qt Creator.
+  * Write the handlers manually in a project managed by something other than Qt Creator.
 ==== Do it "visually" ====
@@ Line 105: / Line 110: @@
 You can explicitly connect signals and slots programatically. This is typically done in a form's constructor.
-<code cpp>
+<code cpp-qt>
 HelloForm::HelloForm()
 {
     widget.setupUi(this);
-    connect(widget.button_quit, SIGNAL(clicked()),
+    connect(widget.button_quit, SIGNAL(clicked()), this, SLOT(close()));
-            this, SLOT(close()));
 }</code>
 ===== Runtime signal→slot connection modifications =====
 I don't know. But it should be possible.