How to understand this snippet of Kotlin code?
I come from Java and I'm following a tutorial online regarding using the Volley library to make web requests in Android.
The instructor created the request variable like this:
val registerRequest = object : StringRequest(Method.POST, URL_REGISTER, Response.Listener {
println(it) // will print the response
complete(true)
}, Response.ErrorListener {
Log.d("ERROR", "Could not register user: $it")
complete(false)
}) {
override fun getBodyContentType(): String {
return "application/json; charset=utf-8"
}
override fun getBody(): ByteArray {
return requestBody.toByteArray()
}
}
I understand that he's creating a registerRequest variable of type StringRequest. But what I don't understand is why he prefixed StringRequest with object : here.
Also I understand that StringRequest constructor takes in an Int, String, Lambda, Lambda. After that it becomes confusing to me because the developer was able to declare some override methods after the constructor closes. Why did they do this? From what I can tell, this is similar to subclassing StringRequest, then writing the override methods there? Am I right?
Coming from Java, this way of writing code is quite unusual to me.
kotlin android-volley
edited Nov 23 '18 at 19:20
halfer
14.3k758109
asked Nov 23 '18 at 13:35
fishhau
184
add a comment |
I come from Java and I'm following a tutorial online regarding using the Volley library to make web requests in Android.
The instructor created the request variable like this:
val registerRequest = object : StringRequest(Method.POST, URL_REGISTER, Response.Listener {
println(it) // will print the response
complete(true)
}, Response.ErrorListener {
Log.d("ERROR", "Could not register user: $it")
complete(false)
}) {
override fun getBodyContentType(): String {
return "application/json; charset=utf-8"
}
override fun getBody(): ByteArray {
return requestBody.toByteArray()
}
}
I understand that he's creating a registerRequest variable of type StringRequest. But what I don't understand is why he prefixed StringRequest with object : here.
Also I understand that StringRequest constructor takes in an Int, String, Lambda, Lambda. After that it becomes confusing to me because the developer was able to declare some override methods after the constructor closes. Why did they do this? From what I can tell, this is similar to subclassing StringRequest, then writing the override methods there? Am I right?
Coming from Java, this way of writing code is quite unusual to me.
kotlin android-volley
edited Nov 23 '18 at 19:20
halfer
14.3k758109
asked Nov 23 '18 at 13:35
fishhau
184
3
it's an anonymous class, see kotlinlang.org/docs/reference/…. In java you would have seen= new StringRequest()...
– Tim Castelijns
Nov 23 '18 at 13:37
@TimCastelijns Ah that makes sense. Didn't know that you could do this stuff in Kotlin as it's a very different practice from Java. Thanks!
– fishhau
Nov 25 '18 at 3:35
1
You need to read and understand a breadth of Kotlin before dropping into reading random code. Make sure you have wall to wall coverage over Kotlin otherwise you'll keep finding mysterious code that you do not have the toolkit to decipher.
– Jayson Minard
Nov 25 '18 at 14:43
Thanks for the advice. I am actually taking a Kotlin online course right now to get more comfortable with the language.
– fishhau
Nov 26 '18 at 3:28
add a comment |
I come from Java and I'm following a tutorial online regarding using the Volley library to make web requests in Android.
The instructor created the request variable like this:
val registerRequest = object : StringRequest(Method.POST, URL_REGISTER, Response.Listener {
println(it) // will print the response
complete(true)
}, Response.ErrorListener {
Log.d("ERROR", "Could not register user: $it")
complete(false)
}) {
override fun getBodyContentType(): String {
return "application/json; charset=utf-8"
}
override fun getBody(): ByteArray {
return requestBody.toByteArray()
}
}
I understand that he's creating a registerRequest variable of type StringRequest. But what I don't understand is why he prefixed StringRequest with object : here.
Also I understand that StringRequest constructor takes in an Int, String, Lambda, Lambda. After that it becomes confusing to me because the developer was able to declare some override methods after the constructor closes. Why did they do this? From what I can tell, this is similar to subclassing StringRequest, then writing the override methods there? Am I right?
Coming from Java, this way of writing code is quite unusual to me.
kotlin android-volley
edited Nov 23 '18 at 19:20
halfer
14.3k758109
asked Nov 23 '18 at 13:35
fishhau
184
I come from Java and I'm following a tutorial online regarding using the Volley library to make web requests in Android.
The instructor created the request variable like this:
val registerRequest = object : StringRequest(Method.POST, URL_REGISTER, Response.Listener {
println(it) // will print the response
complete(true)
}, Response.ErrorListener {
Log.d("ERROR", "Could not register user: $it")
complete(false)
}) {
override fun getBodyContentType(): String {
return "application/json; charset=utf-8"
}
override fun getBody(): ByteArray {
return requestBody.toByteArray()
}
}
I understand that he's creating a registerRequest variable of type StringRequest. But what I don't understand is why he prefixed StringRequest with object : here.
Also I understand that StringRequest constructor takes in an Int, String, Lambda, Lambda. After that it becomes confusing to me because the developer was able to declare some override methods after the constructor closes. Why did they do this? From what I can tell, this is similar to subclassing StringRequest, then writing the override methods there? Am I right?
Coming from Java, this way of writing code is quite unusual to me.
kotlin android-volley
kotlin android-volley
edited Nov 23 '18 at 19:20
halfer
14.3k758109
asked Nov 23 '18 at 13:35
fishhau
184
edited Nov 23 '18 at 19:20
halfer
14.3k758109
asked Nov 23 '18 at 13:35
fishhau
184
edited Nov 23 '18 at 19:20
halfer
14.3k758109
edited Nov 23 '18 at 19:20
halfer
14.3k758109
edited Nov 23 '18 at 19:20
halfer
14.3k758109
14.3k758109
asked Nov 23 '18 at 13:35
fishhau
184
asked Nov 23 '18 at 13:35
fishhau
184
asked Nov 23 '18 at 13:35
fishhau
184
184
3
it's an anonymous class, see kotlinlang.org/docs/reference/…. In java you would have seen= new StringRequest()...
– Tim Castelijns
Nov 23 '18 at 13:37
@TimCastelijns Ah that makes sense. Didn't know that you could do this stuff in Kotlin as it's a very different practice from Java. Thanks!
– fishhau
Nov 25 '18 at 3:35
1
You need to read and understand a breadth of Kotlin before dropping into reading random code. Make sure you have wall to wall coverage over Kotlin otherwise you'll keep finding mysterious code that you do not have the toolkit to decipher.
– Jayson Minard
Nov 25 '18 at 14:43
Thanks for the advice. I am actually taking a Kotlin online course right now to get more comfortable with the language.
– fishhau
Nov 26 '18 at 3:28
add a comment |
3
it's an anonymous class, see kotlinlang.org/docs/reference/…. In java you would have seen= new StringRequest()...
– Tim Castelijns
Nov 23 '18 at 13:37
@TimCastelijns Ah that makes sense. Didn't know that you could do this stuff in Kotlin as it's a very different practice from Java. Thanks!
– fishhau
Nov 25 '18 at 3:35
1
You need to read and understand a breadth of Kotlin before dropping into reading random code. Make sure you have wall to wall coverage over Kotlin otherwise you'll keep finding mysterious code that you do not have the toolkit to decipher.
– Jayson Minard
Nov 25 '18 at 14:43
Thanks for the advice. I am actually taking a Kotlin online course right now to get more comfortable with the language.
– fishhau
Nov 26 '18 at 3:28
3
3
it's an anonymous class, see kotlinlang.org/docs/reference/…. In java you would have seen
= new StringRequest()...– Tim Castelijns
Nov 23 '18 at 13:37
it's an anonymous class, see kotlinlang.org/docs/reference/…. In java you would have seen
= new StringRequest()...– Tim Castelijns
Nov 23 '18 at 13:37
@TimCastelijns Ah that makes sense. Didn't know that you could do this stuff in Kotlin as it's a very different practice from Java. Thanks!
– fishhau
Nov 25 '18 at 3:35
@TimCastelijns Ah that makes sense. Didn't know that you could do this stuff in Kotlin as it's a very different practice from Java. Thanks!
– fishhau
Nov 25 '18 at 3:35
1
1
You need to read and understand a breadth of Kotlin before dropping into reading random code. Make sure you have wall to wall coverage over Kotlin otherwise you'll keep finding mysterious code that you do not have the toolkit to decipher.
– Jayson Minard
Nov 25 '18 at 14:43
You need to read and understand a breadth of Kotlin before dropping into reading random code. Make sure you have wall to wall coverage over Kotlin otherwise you'll keep finding mysterious code that you do not have the toolkit to decipher.
– Jayson Minard
Nov 25 '18 at 14:43
Thanks for the advice. I am actually taking a Kotlin online course right now to get more comfortable with the language.
– fishhau
Nov 26 '18 at 3:28
Thanks for the advice. I am actually taking a Kotlin online course right now to get more comfortable with the language.
– fishhau
Nov 26 '18 at 3:28
add a comment |
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3
it's an anonymous class, see kotlinlang.org/docs/reference/…. In java you would have seen
= new StringRequest()...– Tim Castelijns
Nov 23 '18 at 13:37
@TimCastelijns Ah that makes sense. Didn't know that you could do this stuff in Kotlin as it's a very different practice from Java. Thanks!
– fishhau
Nov 25 '18 at 3:35
1
You need to read and understand a breadth of Kotlin before dropping into reading random code. Make sure you have wall to wall coverage over Kotlin otherwise you'll keep finding mysterious code that you do not have the toolkit to decipher.
– Jayson Minard
Nov 25 '18 at 14:43
Thanks for the advice. I am actually taking a Kotlin online course right now to get more comfortable with the language.
– fishhau
Nov 26 '18 at 3:28