Kotlin ArrayAdapter 错误:以下任何函数都不能使用提供的参数调用

Question

我是 Kotlin Android 开发的新手。在遵循教程项目时，我需要将ArrayAdapter与自定义类一起使用。生成项目失败并显示错误。

引发错误的 MainActivity.kt 类：

class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setSupportActionBar(toolbar)
}
val dm = DataManager()
val adapterCourses = ArrayAdapter<CourseInfo>(
context = this,
android.R.layout.simple_spinner_item,
dm.courses.values.toList()
)
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if it is present.
menuInflater.inflate(R.menu.menu_main, menu)
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
return when (item.itemId) {
R.id.action_settings -> true
else -> super.onOptionsItemSelected(item)
}
}
}

错误：

None of the following functions can be called with the arguments supplied:
public constructor ArrayAdapter<T : Any!>(@RecentlyNonNull p0: Context!, p1: Int) defined in android.widget.ArrayAdapter
public constructor ArrayAdapter<T : Any!>(@RecentlyNonNull p0: Context!, p1: Int, @RecentlyNonNull p2: Array<(out) CourseInfo!>!) defined in android.widget.ArrayAdapter
public constructor ArrayAdapter<T : Any!>(@RecentlyNonNull p0: Context!, p1: Int, p2: Int) defined in android.widget.ArrayAdapter
public constructor ArrayAdapter<T : Any!>(@RecentlyNonNull p0: Context!, p1: Int, p2: Int, @RecentlyNonNull p3: Array<(out) CourseInfo!>!) defined in android.widget.ArrayAdapter
public constructor ArrayAdapter<T : Any!>(@RecentlyNonNull p0: Context!, p1: Int, p2: Int, @RecentlyNonNull p3: (Mutable)List<CourseInfo!>!) defined in android.widget.ArrayAdapter
public constructor ArrayAdapter<T : Any!>(@RecentlyNonNull p0: Context!, p1: Int, @RecentlyNonNull p2: (Mutable)List<CourseInfo!>!) defined in android.widget.ArrayAdapter

课程信息课：

class CourseInfo (val courseId: String, val title: String)

数据管理器类：

class DataManager {
val courses = HashMap<String, CourseInfo>()
val notes = ArrayList<NoteInfo>()
init {
initializeCourses()
}
private fun initializeCourses () {
var course = CourseInfo(courseId = "android_intent", title = "Android programming with intent.")
this.courses.set(course.courseId, course)
course = CourseInfo(courseId = "android_async", title = "Android Async Programming and Services.")
courses.set(course.courseId, course)
course = CourseInfo(courseId = "java_lang", title = "Java Fundamentals: The Java Language.")
courses.set(course.courseId, course)
course = CourseInfo(courseId = "java_core", title = "Java Fundamentals: The Core Platforms.")
courses.set(course.courseId, course)
}
}

Answer 1

也许为时已晚，但也许它可以帮助某人。如果您正在使用片段，则选中的答案将无法解决该问题。必须像这样调用活动上下文。

val adapter = activity?.let {
ArrayAdapter<String>(
it,
android.R.layout.simple_spinner_item,
campaignsType
)
}

Answer 2

非 kotlin 函数不允许使用命名参数。

问题是因为你在 kotlin 文件中调用了javaArrayAdapter构造函数。 您将无法为其提供参数标签。

因此，遵循简单的更正将解决问题。(请注意，我删除了第一个参数中的上下文标签。

val adapterCourses = ArrayAdapter<CourseInfo>(this,
android.R.layout.simple_spinner_item,
dm.courses.values.toList())

Answer 3

调用requireContext((来代替上下文参数

Answer 4

使用以下代码

val courseList:List<CourseInfo>= dm.courses.values.toList()
val adapterCourses = ArrayAdapter<CourseInfo>(this,android.R.layout.simple_spinner_item,courseList)

Answer 5

val adapters = activity？.let { ArrayAdapter(it.applicationContext， R.layout.support_simple_spinner_dropdown_item， stringArray( } as SpinnerAdapter