160308_signals & Slots

In Qt, we have a alternative to the callback technique:we use signals and slots. A signal is emitted when a particular event occurs. Qt ' s widgets has many predefined signals, but we can always subclass widgets to add our own signals to them. A slot is a function, which is called-response to a particular signal. Qt ' s widgets has many pre-defined slots, but it's common practice to subclass widgets and add your own slots so this you Can handle the signals that is interested in.

　

　　

160308_signals & Slots