在我的项目中，我正在使用凌空下载一个JSON流，我将其解析并显示在列表视图中。我使用以下方法加载数据：
private void loadEventData(int year, final int month) {
// get volley request queue
requestQueue = cpcApplication.getRequestQueue(getActivity());
String url = "****************?year=" + year
+ "&month=" + month;
pd = ProgressDialog.show(getActivity(), "Loading Events", "Retrieving Data from Server");
pd.setCancelable(true);
JsonObjectRequest jr = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.i(TAG, response.toString());
// parse the incoming response
parseJson(response, month);
// notify the listview that the data set has changed
adapter.notifyDataSetChanged();
// set the listview at the top position
listView.setSelection(current.get(Calendar.DAY_OF_MONTH));
// dismiss the ProgressDialog
pd.dismiss();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
// cancel the progress dialog
pd.dismiss();
// let the user know that a network connection is not available
Toast.makeText(getActivity(), "Cannot communicate with server. Check network connection.", Toast.LENGTH_LONG).show();
}
});
// add the network request to the queue
requestQueue.add(jr);
}
首次调用此方法的效果很好。在第二个呼叫中，出现超时错误。当我使用以下命令时：
jr.setRetryPolicy(new DefaultRetryPolicy(
2500, DefaultRetryPolicy.DEFAULT_TIMEOUT_MS, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
为了增加请求的时间，请求将花费30秒以上的时间，并产生以下日志输出：
10-19 20:53:19.746: D/Volley(17523): [2786] BasicNetwork.logSlowRequests: HTTP response for request=<[ ] http://************ 0x63ea5535 NORMAL 1> [lifetime=41769], [size=5467846], [rc=200], [retryCount=2]
10-19 20:53:19.796: D/dalvikvm(17523): GC_CONCURRENT freed 7462K, 26% free 24424K/33000K, paused 6ms+4ms, total 56ms
10-19 20:53:19.796: D/dalvikvm(17523): WAIT_FOR_CONCURRENT_GC blocked 51ms
10-19 20:53:19.826: I/dalvikvm-heap(17523): Grow heap (frag case) to 35.123MB for 10935708-byte allocation
10-19 20:53:19.857: D/dalvikvm(17523): GC_FOR_ALLOC freed 3K, 20% free 35100K/43680K, paused 23ms, total 28ms
10-19 20:53:19.917: D/dalvikvm(17523): GC_CONCURRENT freed 2018K, 19% free 35816K/43680K, paused 3ms+4ms, total 60ms
10-19 20:53:20.007: D/dalvikvm(17523): GC_CONCURRENT freed 4874K, 15% free 37226K/43680K, paused 2ms+3ms, total 27ms
10-19 20:53:20.007: D/dalvikvm(17523): WAIT_FOR_CONCURRENT_GC blocked 24ms
10-19 20:53:20.067: D/dalvikvm(17523): GC_FOR_ALLOC freed 5037K, 15% free 38601K/44900K, paused 19ms, total 19ms
10-19 20:53:20.117: D/dalvikvm(17523): GC_FOR_ALLOC freed 4680K, 14% free 40045K/46564K, paused 20ms, total 20ms
10-19 20:53:20.177: D/dalvikvm(17523): GC_FOR_ALLOC freed 5576K, 14% free 41572K/48272K, paused 20ms, total 20ms
10-19 20:53:20.227: D/dalvikvm(17523): GC_FOR_ALLOC freed 6133K, 15% free 43406K/50548K, paused 20ms, total 20ms
10-19 20:53:20.287: D/dalvikvm(17523): GC_CONCURRENT freed 6486K, 15% free 45029K/52428K, paused 2ms+2ms, total 24ms
10-19 20:53:20.287: D/dalvikvm(17523): WAIT_FOR_CONCURRENT_GC blocked 11ms
10-19 20:53:20.407: D/Volley(17523): [1] Request.finish: 42553 ms: [ ] http://****** 0x63ea5535 NORMAL 1
当我在浏览器中执行相同的请求时，只需要几秒钟。为什么会有延迟和难以置信的内存消耗？
最佳答案
每次调用该方法都会创建一个新的RequestQueue，这不是推荐的方法。您应该创建一个RequestQueue，可能是一个公开可见的单例，在创建应用程序时初始化一次。
尝试将RequestQueue移到外面，看看是否可以解决您的问题。