If we come from the Java world, these lists may confuse us. Also, when we try to add an element to a list in Kotlin, it’s not always as straightforward as calling theadd()method in Java. For example, sometimes,
```kotlin val mutableList = mutableListOf<Int>() ``` 或者 ```kotlin val mutableList = listOf(1, 2, 3).toMutableList() ``` 2.使用add方法向列表中添加元素。在Kotlin中,add方法用于将指定的元素添加到列表的末尾。 示例代码: ```kotlin mutableList.add(4) mutableList.add(5) ``` 在上述示例...
Kotlin不允许往集合中添加null值,虽然签名做了空判断,但是怕在调用addAll时对应值仍然被修改为null(脑子有问题)。 解决方案 方式1. data.list?.let(mDataList::addAll) 方式2. data.list?.let { node -> mDataList.addAll(node) } 方式3. data.list?.let { mD...
var data = listOf(1,2,3) } 1. 2. 3. 对象声明的特点是object关键字后面跟着一个名称。就像声明一个变量那样,但是对象声明不是一个表达式,不能把对象声明放在赋值语句的右边。 利用AndroidStudio 的 Show Kotlin Bytecode 功能,看一下对应的 .java 文件: public final class DataRepository { @NotNull pr...
# Advent of Code in Kotlin ## Scripts ```sh ./run.sh [FILENAME] # Run with FILENAME (defaults to input.txt) ./test.sh # Run the tests ``` ## Watch Mode ```sh fd | entr -cc ./run.sh [FILENAME] fd | entr -cc ./test.sh ``` 55 changes: 55 additions & 0 deletions ...
MutableList 是Kotlin 中的一个接口,它继承自 List 接口,并添加了可变操作的方法。clear() 和addAll() 是MutableList 接口中用于修改列表内容的两个常用方法。 基础概念 clear(): 这个方法用于移除列表中的所有元素,使得列表变为空。 addAll(): 这个方法用于将一个集合中的所有元素添加到列表的末尾。 行为解...
32 + // (none of the types from these libraries should be part of a public API) 33 + implementation fileTree(dir: "$rootProject.projectDir/libs", include: ['*.jar']) 30 34 } 31 35 32 36 configurations.configureEach { libs/kotlin-metadata.jarCopy file name to clipboard 113...
Example: Adding Ordered List In this example, we add a list in HTML by assigning values to the attributes of the <li> tag. This HTML code creates an ordered list with the heading "The li value attribute." The first item, "Juice," is assigned a value of 200, while the remaining item...
Imagine that you have a data model for companies, each of which has a list of employees. You could use thegetoperator to access the positions using brackets. The implementation is very easy: classEmployee(valid:Long,valname:String)classCompany(privatevalemployees:List<Employee>) {operatorfunget...
You will create aGraphicsOverlay. Then add the graphics overlay to a list namedgraphicsOverlays. More info For information about remembering state between recompositions in Android Jetpack Compose, seeState and Jetpack Compose. In subsequent sections of this tutorial, you will create a point, a line...