1. Volley를 사용하겠다고 build.gradle에 선언해준다(매니페스트에 인터넷 사용은 당연한것!)
dependencies {
implementation 'com.android.volley:volley:1.1.1'
/* 생략 */
}
2. RequestQueue를 한번만 생성하도록 싱글톤으로 만든다
(출처 : developer.android.com/training/volley/requestqueue?hl=ko)
public class MySingleton {
private static MySingleton instance;
private RequestQueue requestQueue;
private ImageLoader imageLoader;
private static Context ctx;
private MySingleton(Context context) {
ctx = context;
requestQueue = getRequestQueue();
imageLoader = new ImageLoader(requestQueue,
new ImageLoader.ImageCache() {
private final LruCache<String, Bitmap>
cache = new LruCache<String, Bitmap>(20);
@Override
public Bitmap getBitmap(String url) {
return cache.get(url);
}
@Override
public void putBitmap(String url, Bitmap bitmap) {
cache.put(url, bitmap);
}
});
}
public static synchronized MySingleton getInstance(Context context) {
if (instance == null) {
instance = new MySingleton(context);
}
return instance;
}
public RequestQueue getRequestQueue() {
if (requestQueue == null) {
// getApplicationContext() is key, it keeps you from leaking the
// Activity or BroadcastReceiver if someone passes one in.
requestQueue = Volley.newRequestQueue(ctx.getApplicationContext());
}
return requestQueue;
}
public <T> void addToRequestQueue(Request<T> req) {
getRequestQueue().add(req);
}
public ImageLoader getImageLoader() {
return imageLoader;
}
}
3. 사용하고 싶은 곳에서 호출한다
3-1. 이렇게 위에서 만든 싱글톤으로 사용하거나
RequestQueue queue = MySingleton.getInstance(this.getApplicationContext()).
getRequestQueue();
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Display the first 500 characters of the response string.
textView.setText("Response is: "+ response.substring(0,500));
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
textView.setText("That didn't work!");
}
});
// Add the request to the RequestQueue.
queue.add(stringRequest);
3-2. 그냥 바로 겟인스턴스해서 써도 된다
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Display the first 500 characters of the response string.
textView.setText("Response is: "+ response.substring(0,500));
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
textView.setText("That didn't work!");
}
});
// Add the request to the RequestQueue.
MySingleton.getInstance(this).addToRequestQueue(stringRequest);
4. 파라미터로 요청을 보내고 싶다면 getParmas를 사용해 Map에 담아 보내면 된다. StringRequest, POST에서만 된다. JsonRequest에서는 안됨.
StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Display the first 500 characters of the response string.
textView.setText("Response is: "+ response.substring(0,500));
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
textView.setText("That didn't work!");
}
}){
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("key", value);
params.put("key", value);
return params;
}
};
// Add the request to the RequestQueue.
queue.add(stringRequest);
5. json으로 받고싶다면 argument 하나가 중간에 추가된다.
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
queue.add(jsonObjectRequest);
자세한건 여기에 더 있다
https://developer.android.com/training/volley?hl=ko
