如何从kotlin中的函数返回值

1 回答

• 8

  Kotlin只能在表达式时推断出函数的返回类型，所以如果你的函数有一个体，你需要在函数参数后指定返回的类型

  fun functionName(param: Type...): ReturnedType { 
      //function body
  }
  
  fun  validateDetails(jabberId:String, passwordText: String):Boolean {
  
              if(jabberId.isEmpty()){
                  jabber_id.requestFocus()
                  jabber_id.error="Jabber id can't be null."
                   return false
              }else if(jabberId.isBlank()){
               jabber_id.requestFocus()
               jabber_id.error="Jabber id can't be blank."
                return false
              }else if (passwordText.isNotEmpty()){
                  password.requestFocus();
                  password.error="Password can't be null."
                   return false
              }
               else{
                   return true
              }   
  
      }
  

  正如glee8e所提到的，这可以使用表达式来完成 . 这就是它的完成方式 .

  fun  validateDetails(jabberId:String, passwordText: String) = when {
      jabberId.isEmpty() -> {
          jabber_id.requestFocus()
          jabber_id.error="Jabber id can't be null."
  
          false
      }
  
      jabberId.isBlank() -> {
          jabber_id.requestFocus()
          jabber_id.error="Jabber id can't be blank."
  
          false
      }
  
      passwordText.isNotEmpty() -> {
          password.requestFocus();
          password.error="Password can't be null."
          false
      }
  
      else -> true  
  }
  

  回复于 2024-05-06T05:56:12+08:00