Volley: 强制缓存

ForceCacheing.java

...

protected Response<?> parseNetworkResponse(NetworkResponse response) {
      try {
          String json = new String(response.data,
                  HttpHeaderParser.parseCharset(response.headers));
          ... // parseing json
          
          return Response.success(obj, cache(response, 60));
      } catch (Exception e) {
          Log.e(TAG, "parse article error", e);
          return Response.error(new ParseError(e));
      }
  }
  
...

public static Cache.Entry cache(NetworkResponse response, long maxAge){
    long now = System.currentTimeMillis();
    if(maxAge == 0) maxAge = 60;
    Map<String, String> headers = response.headers;

    long serverDate = 0;
    long softExpire = 0;
    String serverEtag = null;
    String headerValue;

    headerValue = headers.get("Date");
    if (headerValue != null) {
        serverDate = HttpHeaderParser.parseDateAsEpoch(headerValue);
    }
    softExpire = now + maxAge * 1000;
    Cache.Entry entry = new Cache.Entry();
    entry.data = response.data;
    entry.etag = serverEtag;
    entry.softTtl = softExpire;
    entry.ttl = entry.softTtl;
    entry.serverDate = serverDate;
    entry.responseHeaders = headers;
    return entry;
  }