顶层函数
Kotlin中函数站在了类的位置,可以直接把函数放在代码文件的顶层,不属于任何类
package com.zhoujian.kotlindemo.util
fun <T> joinToString(collection: Collection<T>, separator: String = ",", prefix: String = "", postfix: String = ""): String {
val resault = StringBuffer(prefix)
for ((index, element) in collection.withIndex()) {
if (index > 0) resault.append(separator)
resault.append(element)
}
resault.append(postfix)
return resault.toString()
}
import com.zhoujian.kotlindemo.util.joinToString
val list = listOf(1, 2, 3)
Log.i("zhoujian", "list=" + joinToString(list, ";", "(", ")"));
通过import 包名.函数名
来导入我们将要使用的函数
顶层属性
package com.zhoujian.kotlindemo.config
//可变参数(getter和setter)
var count = 1
//不可变参数(getter)
val REQUEST_URL = "http://localhost:8080/"
//常量(类似于Java:public static final)
const val BASE_URL = "http://www.baidu.com/"