for interface builder
For compilation, IBOutlet and IBAction didn't do anything. To put it bluntly, IBOutlet and IBAction are markup symbols,.
For example: attribute declarations
@property (weak, nonatomic) IBOutlet UITextField
Link this property to a TextField control in interface builder, where the IBOutlet identifies the property here, which corresponds to the uinterface builder control.
You need to create any link to the nib file instance variables must begin with IBOutlet, open the interface builder, he will scan this keyword in the project file, you can according to these, can only be based on these variables will be linked to the nib code in.
For example, this: Declaration of methods,
triggered by a control
The IBAction here tells interface builder, which is an operation (action) and a .r