[Android] Convert Map to JSON using GSON in Kotlin and Java
Introduction
GSON is a JSON parsing library provided by Google. You can convert Java objects and JSON, but Kotlin can. This time, I could easily convert it with Kotlin's MutableMap, so I would like to share it.
How to use GSON
Write the following in Android Studio.
build.gradle
dependencies {
implementation 'com.google.code.gson:gson:*.*.*'
}
"*. *. *" Describe the latest version. Check the latest version from the following. https://github.com/google/gson
After writing the above, click "Sync Now" on Android Studio and you're ready to go.
GSON is now available in your project.
JSON conversion of Java Map
I implemented the JSON conversion process as follows.
Sample.java
public void test(){
ArrayMap<String, String> map = new ArrayMap<>();
map.put("a1", "A1");
map.put("a2", "A2");
map.put("a3", "A3");
Gson gson = new Gson();
String jsonString = gson.toJson(map);
Log.d("Java", jsonString);
Type type = new TypeToken<ArrayMap<String, String>>(){}.getType();
ArrayMap<String, String> map2 = gson.fromJson(jsonString, type);
for (String mapValue : map2.values()) {
Log.d("Java", mapValue);
}
}
When you check the log
D/Java: {"a1":"A1","a2":"A2","a3":"A3"} D/Java: A1 A2 A3
become that way. It was confirmed that JSON conversion is possible. Up to this point, it's been done before, so there's nothing new.
JSON conversion of Kotlin Map
The main subject is from here. Implement the above Java implementation in Kotlin. Map uses Kotlin's MutableMap.
Sample.kt
fun test(){
val map : MutableMap<String, String> = mutableMapOf()
map.put("a1", "A1")
map.put("a2", "A2")
map.put("a3", "A3")
val gson = Gson()
val jsonString : String = gson.toJson(map)
Log.d("Kotlin", jsonString)
val type : Type = object : TypeToken<MutableMap<String, String>>() {}.type
val map2 : MutableMap<String, String> = gson.fromJson(jsonString, type)
for (mapValue in map2.values) {
Log.d("Kotlin", mapValue)
}
}
When you check the log
D/Kotlin: {"a1":"A1","a2":"A2","a3":"A3"} D/Kotlin: A1 A2 A3
become that way. It was confirmed that JSON conversion can be performed in the same way as Java.
At the end
The ease of use of Kotlin is GOOD!
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