Java 如何在 Kotlin 中访问“Activity.this”？
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How to access "Activity.this" in Kotlin?
提问by Bal0r
I have this piece of Java code:
我有这段Java代码：
MaterialDialog builder = new MaterialDialog.Builder(MainActivity.this)
I want to get the MainActivity object in Kotlin. The automatic conversion breaks at MainActivity.this.
我想在 Kotlin 中获取 MainActivity 对象。自动转换在 处中断MainActivity.this。
采纳答案by mfulton26
You can get a reference to your MainActivityobject in Kotlin by using a qualified this. e.g.:
您可以MainActivity在 Kotlin 中使用限定的this. 例如：
class MyActivity : MainActivity() {
val builder = MaterialDialog.Builder(this@MyActivity)
}
回答by The Bala
Try this label instead
试试这个标签
this@YourActivityName
回答by Allen
If you are calling Activity.this from an inner class, you have to put innerbefore the class
如果您从内部类调用 Activity.this，则必须将内部放在类之前
class MyActivity : MainActivity() {
// Call from class itself
val builder = MaterialDialog.Builder(this@MyActivity)
inner class Inner {
this@MyActivity // Call from the inner class
}
}
回答by Shivam Yadav
Just as you do in java for getting the context of activity as MainActivtiy.this , in kotlin you will get the context as this@MainActivity
就像你在 java 中获取活动上下文作为 MainActivtiy.this 一样，在 kotlin 中你将获得作为this@MainActivity的上下文
回答by Mechadroid
getActivity()equivalent is this@activity_namein case of builder for materialDialog
getActivity()等效this@activity_name于 materialDialog builder 的情况
materialDialog = MaterialDialog.Builder(this)
回答by Nikhil Katekhaye
You can get the object of activity like this.
您可以像这样获取活动对象。
class DemoActivity : MainActivity() {
val builder = MaterialDialog.Builder(this@DemoActivity)
}
回答by canerkaseler
In Kotlin, you have to use this way:
在 Kotlin 中，你必须这样使用：
this@ActivityName
这个@ActivityName
For example: You should use it if you would like to define "Context" in MainActivity.kt
例如：如果你想在 MainActivity.kt 中定义“Context”，你应该使用它
var mContext:Context = this@MainActivity
Why? Because in Kotlin language @ has mean "of" such as:
为什么？因为在 Kotlin 语言中 @ 的意思是“of”，例如：
val a = this@A // A's this
If you want to learn more information, you can look Kotlin Language website: This Expression in Kotlin
如果您想了解更多信息，可以查看 Kotlin 语言网站： Kotlin 中的这个表达式
@canerkaseler
@canerkaseler
