Question

在其他语言（如C或Java）中，如果我想停止执行一个方法并返回一个我喜欢的值：

@IBAction func button_1(sender: AnyObject) {
     if a == b
     {
        // Do something ...
        /* I want to stop here but I don't know how */
     }
     // Do something else
}

如果是swift，我为按钮指定一个动作

SELECT 
    p.pub_name
FROM 
    publishers p
WHERE 
    p.pub_id IN (SELECT pub_id FROM titles t WHERE t.category = 'psychology)

如何停止在Action中执行脚本？感谢。

Answer 1

不确定您遇到了什么问题......您可以使用---Has type template bar--- consists_no_bar: false consists_alias: false consists_struct: false consists_class: false consists_union: false consists_variable: false consists_function: false consists_overloaded_func: false consists_reference: false consists_t_alias: true consists_t_struct: true consists_t_class: true consists_t_union: true consists_t_variable: false consists_t_function: false consists_t_overloaded_function: false consists_s_variable: false consists_s_function: false consists_s_overloaded_func: false consists_s_t_function: false consists_s_t_overloaded_function: false --Has member function template bar--- consists_no_bar: false consists_alias: false consists_struct: false consists_class: false consists_union: false consists_variable: false consists_function: false consists_overloaded_func: true // implmementation bug consists_reference: false consists_t_alias: false consists_t_struct: false consists_t_class: false consists_t_union: false consists_t_variable: false consists_t_function: true consists_t_overloaded_function: true consists_s_variable: false consists_s_function: false consists_s_overloaded_func: true // implmementation bug consists_s_t_function: true consists_s_t_overloaded_function: true --Has member variable template bar--- consists_no_bar: false consists_alias: false consists_struct: false consists_class: false consists_union: false consists_variable: false consists_function: false consists_overloaded_func: false consists_reference: false consists_t_alias: false consists_t_struct: false consists_t_class: false consists_t_union: false consists_t_variable: true consists_t_function: false consists_t_overloaded_function: false consists_s_variable: false consists_s_function: false consists_s_overloaded_func: false consists_s_t_function: false consists_s_t_overloaded_function: false --Has any member template bar--- consists_no_bar: false consists_alias: false consists_struct: false consists_class: false consists_union: false consists_variable: false consists_function: false consists_overloaded_func: true // implmementation bug consists_reference: false consists_t_alias: true consists_t_struct: true consists_t_class: true consists_t_union: true consists_t_variable: true consists_t_function: true consists_t_overloaded_function: true consists_s_variable: false consists_s_function: false consists_s_overloaded_func: true // implmementation bug consists_s_t_function: true consists_s_t_overloaded_function: true就好了。

return

按预期工作。

Answer 2

您可以在某些条件下使用return语句退出函数作用域，例如guard statment 例如：

  @IBAction func SendAction(sender: UIButton) {
guard a != b else {
    // Do something
    return
}
// Do something else

}

如何在Swift中停止执行操作？

2 个答案: