Get non-static string from static method

Question

I'm getting an error when I try to get a non-static string in a static class.

this is the warning message "non static field cannot be referenced from a static context"

I want to get DOWNLOAD_URL String value to put in VIDEO_URL, but VIDEO_URL just get null value, how should I do that?

This is my code:

package com.sa.asd.ax

public class VideoProvider {

    String DOWNLOAD_URL;
    public static List<MediaInfo> buildMedia(String url) throws JSONException {

        if (null != mediaList) {
            return mediaList;
        }
        Map<String, String> urlPrefixMap = new HashMap<>();
        mediaList = new ArrayList<MediaInfo>();
        String VIDEO_URL = null;
        String mimeType = null;
         for (int k = 0; k < videoSpecs.length(); k++) {
            JSONObject videoSpec = videoSpecs.getJSONObject(k);
              if(TARGET_FORMAT.equals(videoSpec.getString(TAG_VIDEO_TYPE))){
                    String youtubeLink = urlPrefixMap.get(TARGET_FORMAT) + videoSpec.getString(TAG_VIDEO_URL);
                    YouTubeUriExtractor ytEx = new YouTubeUriExtractor(null{
                     @Override
                    public void onUrisAvailable(String videoId, String videoTitle, SparseArray<YtFile> ytFiles) {
                    if(ytFiles!=null){
                        int itag = 22; // a YouTube format identifier
                        DOWNLOAD_URL = ytFiles.get(itag).getUrl();
                                     }
                }
        };

    ytEx.execute(youtubeLink);
    VIDEO_URL = DOWNLOAD_URL;
    mimeType = videoSpec.getString(TAG_VIDEO_MIME);
    mediaList.add(buildMediaInfo(VIDEO_URL, mimeType));           
                            }
                        }

        return mediaList;
    }


}

Make DOWNLOAD_URL static : static String DOWNLOAD_URL; – Jens Aug 13 '15 at 07:56 — Jens, Aug 13 '15 at 07:56

score 0 · Answer 1 · answered Aug 13 '15 at 07:57

buildMedia() is a static (class) method - it does not need an instance of VideoProvider to be invoked.

However, the string DOWNLOAD_URL is not static (it's an instance variable), and is tied to a specific instance, and thus it will fail.

What will happen if you do:

VideoProvider.buildMedia(someString);

Which DOWNLOAD_URL will you use in the method itself?

You can make the method unstatic, or make the String object static (class variable instead of instance variable) to solve it.

Get non-static string from static method

1 Answers1