void MyClass::keyPressEvent(QKeyEvent *event) { if (event->key() == Qt::Key_Escape) { // 当按下 Esc 键时,关闭应用程序 close(); } else { // 其他情况下,交由基类处理 QWidget::keyPressEvent(event); } }在这个示例中,我们重写了 “keyPressEvent” 函数,用于处理 Esc 键的按下事件。
signal <name>[([<type> <parameter name>[, ...]])] 2、Loader是专门用来动态创建组件的,它可以从QML文件中创建组件,也可以指定sourceComponent来创建,这里的示例,因为组件是嵌入在主QML文件中定义的,所以使用了sourceComponent方式 6.1.4 信号与槽的连接 1、signal是个对象,它也有一个connect()方法,你可以...
C++内置的异常处理语法try catch用法,在某种情况下使用异常处理可以使代码更加简洁. 不使用异常的伪代码 ...
void QMetaObject::activate(QObject *sender, int from_signal_index, int to_signal_index, void **argv) { // [... other code ...] // emit signals in the following order: from_signal_index <= signals <= to_signal_index, signal < 0 for (int signal = from_signal_index; (signal >...
} catch (e) { print(e); } Emitting Signals from Scripts To emit a signal from script code, you simply invoke the signal function, passing the relevant arguments: myQObject.somethingChanged("hello"); Overloaded Signals and Slots When a signal or slot is overloaded, QtScript will attempt to...
When an object is deleted, it emits a destroyed() signal. You can catch this signal to avoid dangling references to QObjects. QObjects can receive events through event() and filter the events of other objects. See installEventFilter() and eventFilter() for details. A convenience handler, chi...
It is also possible to catch the thrown error in JavaScript: // qmlFile.qmlfunction someFunction() {...var text;try{ text=FileAccess.readFileAsText("/path/to/file.txt"); }catch(error) { console.warn("In "+error.fileName+":"+"error.lineNumber"+": "+error.message); } } ...
1）客户端给服务器发送了一条将其SYN标志位置1的请求连接建立报文，然后其状态由closed转变为SYN-SENT（...
}catch(conststd::exception&e) { cerr<< e.what() <<endl;return1; }return0; } 客户端需要创建远程对象的代理,并通过代理进行远程调用,代码如下: #include <Ice/Ice.h>#include<Printer.h>#include<stdexcept>usingnamespacestd;usingnamespaceDemo;intmain(intargc,char*argv[]) ...
somethingChanged.connect(myQObject, "slotThatDoesntExist"); } catch (e) { print(e); } 1 2 3 4 55. 在脚本中发射信号要从脚本代码发出信号,只需调用signal函数,并传递相关参数:myQObject.somethingChanged("hello"); 1目前无法在脚本中定义新信号;也就是说,所有的信号必须由C++类定义。