Volley 사용법

1. 권한 설정

<uses-permission android:name="android.permission.INTERNET"/>
<application        
        android:usesCleartextTraffic="true">

2. build.gradle(app)

dependencies {
implementation 'com.android.volley:volley:1.2.1'
}

3. 싱글톤 클래스 생성(RequestQueue 설정)

class MySingleton constructor(context: Context) {
    companion object {
        @Volatile
        private var INSTANCE: MySingleton? = null
        fun getInstance(context: Context) =
            INSTANCE ?: synchronized(this) {
                INSTANCE ?: MySingleton(context).also {
                    INSTANCE = it
                }
            }
    }
    val requestQueue: RequestQueue by lazy {
        // applicationContext is key, it keeps you from leaking the
        // Activity or BroadcastReceiver if someone passes one in.
        Volley.newRequestQueue(context.applicationContext)
    }
    fun <T> addToRequestQueue(req: Request<T>) {
        requestQueue.add(req)
    }
}

4. 사용하기

val url = "http://www.example.com"
// Formulate the request and handle the response.
val stringRequest = StringRequest(Request.Method.GET, url,
         Response.Listener<String> { response ->
            // Do something with the response
        },
        Response.ErrorListener { error ->
            // Handle error
        })
val queue = MySingleton.getInstance(this.applicationContext).requestQueue
queue.add(stringRequest)

- 깃허브 주소 : https://github.com/google/volley