Kotlin:'Int'类型的表达式'长度'不能作为函数调用.找不到函数'invoke()'

Question

我正在尝试解决一个旧的kotlin项目中的问题.但问题是我无法编译代码.我尝试在Android Studio和IntelliJ中编译和运行.我有同样的错误.

以下是错误:

Error:(174, 25) Expression 'length' of type 'Int' cannot be invoked as a function. The function 'invoke()' is not found

Error:(176, 60) Unresolved reference: charAt

Error:(148, 67) Expression 'size' of type 'Int' cannot be invoked as a function. The function 'invoke()' is not found

Error:(107, 76) Expression 'ordinal' of type 'Int' cannot be invoked as a function. The function 'invoke()' is not found

我的gradle脚本:

buildscript {
ext.kotlin_version = '1.0.4'

repositories {
    jcenter()
}
dependencies {
    classpath 'com.android.tools.build:gradle:1.5.0'
    classpath 'com.google.gms:google-services:1.5.0'
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'
}
} 
.
.
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

android {
.
.
sourceSets {
    main.java.srcDirs += 'src/main/kotlin'
}
}

dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}

对于序数错误:

//enum class
enum class Category(val n:Int, val color:Int, val id : String){
   HEADLINE(R.string.category_headline, Color.parseColor("#EC4A42"), "101"),
   .
   .
  }
//where call ordinal func
intent.putExtra(MainActivity.EXTRA_CATEGORY, Category.HEADLINE.ordinal())

对于charAt错误:

companion object{
    fun trim(s : CharSequence) : CharSequence{
        var start = 0
        var end = s.length()

        while (start < end && Character.isWhitespace(s.charAt(start))) {
            start++
        }

        while (end > start && Character.isWhitespace(s.charAt(end - 1))) {
            end--
        }

        return s.subSequence(start, end)
    }
}

长度():

 companion object{
    fun trim(s : CharSequence) : CharSequence{
        var start = 0
        var end = s.length()

        while (start < end && Character.isWhitespace(s.charAt(start))) {
            start++
        }

        while (end > start && Character.isWhitespace(s.charAt(end - 1))) {
            end--
        }

        return s.subSequence(start, end)
    }
}

size()用法:

class PhotoGalleryAdapter(val ac : Activity, val result : ResponseNewsDetail) : PagerAdapter(){
   override fun getCount(): Int = result.gallery!!.size()
   .
   .
 }

任何想法/建议将不胜感激.干杯!

Answer 1

所有那些返回int的方法(String#length(),...)都有一段时间以前成为属性.只需删除括号()并以属性方式使用它.

    var start = 0
    var end = s.length  //without ()

顺便说一句.String已经有了方法trim()

charAt应该由[]操作员替换.因此,更换s.charAt(end-1)用s[end-1]

Answer 2

在 Kotlin 中，表达式 getter 和 setter 与 Java 的不同之处在于没有括号。

吸气剂： 吸气剂 #Class.method ： #Class.method = value

例如

来自：competitions.value(body?.competitionsList)。

到： competitions.value = body?.competitionsList

例如2：

// Gets linearlayout
  val layout: LinearLayout = findViewById(R.id.myLayout)
// Gets the layout params that will allow you to resize the layout
  val params: ViewGroup.LayoutParams = layout.layoutParams
  params.width = 100
  params.height = 100
  layout.layoutParams = params

来源