使用YouTube數據API的YouTube圖像查看

Question

我正在使用YouTube API開發應用程序。我試圖顯示視頻標題&視頻圖像。

我可以顯示視頻標題，但我無法查看任何圖像。

我嘗試了很多事情來解決，但每次我失敗了。 現在我看到一個有一些錯誤的空白頁面。我找出這是什麼樣的錯誤，但我解決不了。

這裏是我的代碼

public class MainActivity extends ActionBarActivity { 
// Declare Variables 
JSONObject jsonobject; 
JSONArray jsonarray; 
ListView listview; 
ListViewAdapter adapter; 
ProgressDialog mProgressDialog; 
ArrayList<HashMap<String, String>> arraylist; 
static String imgURL = "https://www.googleapis.com/youtube/v3/search?part=snippet&maxResult=30&q=natok+bangla+mosharrof+karim&key=AIzaSyCR40QlsuX0aFfBV-wEPDsH_jxna1tDFRA"; 

static String VIDEO_ID = "videoId"; 
static String TITLE = "title"; 
//static String DESCRIPTION = "description"; 
static String THUMBNAILS = "thumbnails"; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    // Get the view from listview_main.xml 
    setContentView(R.layout.listview_main); 
    // Execute DownloadJSON AsyncTask 
    new DownloadJSON().execute(); 
} 

// DownloadJSON AsyncTask 
private class DownloadJSON extends AsyncTask<Void, Void, Void> { 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     // Create a progressdialog 
     mProgressDialog = new ProgressDialog(MainActivity.this); 
     // Set progressdialog title 
     mProgressDialog.setTitle("Your Youtube Video is"); 
     // Set progressdialog message 
     mProgressDialog.setMessage("Loading..."); 
     mProgressDialog.setIndeterminate(false); 
     // Show progressdialog 
     mProgressDialog.show(); 
    } 

    @Override 
    protected Void doInBackground(Void... params) { 
     // Create an array 
     arraylist = new ArrayList<HashMap<String, String>>(); 

     // Retrieve JSON Objects from the given URL address 



     jsonobject = JSONfunctions.getJSONfromURL("https://www.googleapis.com/youtube/v3/search?part=id%2Csnippet&q=natok+2015&maxResults=50&key=AIzaSyCojCp66RLS9OY8hOwnW0UWLNdC56z24Os"); 

     try { 
      // Locate the array name in JSON 
      JSONArray jsonarray = jsonobject.getJSONArray("items"); 

      for (int i = 0; i < jsonarray.length(); i++) { 
       HashMap<String, String> map = new HashMap<String, String>(); 
       jsonobject = jsonarray.getJSONObject(i); 
       // Retrive JSON Objects 
       JSONObject jsonObjId = jsonobject.getJSONObject("id"); 
       map.put("videoId", jsonObjId.getString("videoId")); 

       JSONObject jsonObjSnippet = jsonobject.getJSONObject("snippet"); 
       JSONObject jsonObjThumbnail = jsonobject.getJSONObject("thumbnails"); 
       String imgURL = jsonobject.getJSONObject("default").getString("url"); //use "medium/high" instead of default as required. 
       map.put("title", jsonObjSnippet.getString("title")); 
       map.put("default",jsonObjThumbnail.getString("url")); 









       // Set the JSON Objects into the array 
       arraylist.add(map); 
      } 
     } catch (JSONException e) { 
      Log.e("Error", e.getMessage()); 
      e.printStackTrace(); 
     } 
     return null; 
    } 

    @Override 
    protected void onPostExecute(Void args) { 
     // Locate the listview in listview_main.xml 
     listview = (ListView) findViewById(R.id.listview); 
     // Pass the results into ListViewAdapter.java 
     adapter = new ListViewAdapter(MainActivity.this, arraylist); 
     // Set the adapter to the ListView 
     listview.setAdapter(adapter); 
     // Close the progressdialog 
     mProgressDialog.dismiss(); 
    } 
} 

這裏是我的錯誤我所看到的

12-14 17:56:27.913 6946-6966/amit.jsonparsewithimage E/Error: No value for thumbnails 

這裏是我的ImageLoader的類..

public class ImageLoader { 

MemoryCache memoryCache = new MemoryCache(); 
FileCache fileCache; 
private Map<ImageView, String> imageViews = Collections 
     .synchronizedMap(new WeakHashMap<ImageView, String>()); 
ExecutorService executorService; 
// Handler to display images in UI thread 
Handler handler = new Handler(); 

public ImageLoader(Context context) { 
    fileCache = new FileCache(context); 
    executorService = Executors.newFixedThreadPool(5); 
} 

final int stub_id = R.drawable.temp_img; 

public void DisplayImage(String url, ImageView imageView) { 
    imageViews.put(imageView, url); 
    Bitmap bitmap = memoryCache.get(url); 
    if (bitmap != null) 
     imageView.setImageBitmap(bitmap); 
    else { 
     queuePhoto(url, imageView); 
     imageView.setImageResource(stub_id); 
    } 
} 

private void queuePhoto(String url, ImageView imageView) { 
    PhotoToLoad p = new PhotoToLoad(url, imageView); 
    executorService.submit(new PhotosLoader(p)); 
} 

private Bitmap getBitmap(String url) { 
    File f = fileCache.getFile(url); 

    Bitmap b = decodeFile(f); 
    if (b != null) 
     return b; 

    // Download Images from the Internet 
    try { 
     Bitmap bitmap = null; 
     URL imageUrl = new URL(url); 
     HttpURLConnection conn = (HttpURLConnection) imageUrl 
       .openConnection(); 
     conn.setConnectTimeout(30000); 
     conn.setReadTimeout(30000); 
     conn.setInstanceFollowRedirects(true); 
     InputStream is = conn.getInputStream(); 
     OutputStream os = new FileOutputStream(f); 
     Utils.CopyStream(is, os); 
     os.close(); 
     conn.disconnect(); 
     bitmap = decodeFile(f); 
     return bitmap; 
    } catch (Throwable ex) { 
     ex.printStackTrace(); 
     if (ex instanceof OutOfMemoryError) 
      memoryCache.clear(); 
     return null; 
    } 
} 

// Decodes image and scales it to reduce memory consumption 
private Bitmap decodeFile(File f) { 
    try { 
     // Decode image size 
     BitmapFactory.Options o = new BitmapFactory.Options(); 
     o.inJustDecodeBounds = true; 
     FileInputStream stream1 = new FileInputStream(f); 
     BitmapFactory.decodeStream(stream1, null, o); 
     stream1.close(); 

     // Find the correct scale value. It should be the power of 2. 
     // Recommended Size 512 
     final int REQUIRED_SIZE = 70; 
     int width_tmp = o.outWidth, height_tmp = o.outHeight; 
     int scale = 1; 
     while (true) { 
      if (width_tmp/2 < REQUIRED_SIZE 
        || height_tmp/2 < REQUIRED_SIZE) 
       break; 
      width_tmp /= 2; 
      height_tmp /= 2; 
      scale *= 2; 
     } 

     // Decode with inSampleSize 
     BitmapFactory.Options o2 = new BitmapFactory.Options(); 
     o2.inSampleSize = scale; 
     FileInputStream stream2 = new FileInputStream(f); 
     Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2); 
     stream2.close(); 
     return bitmap; 
    } catch (FileNotFoundException e) { 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return null; 
} 

// Task for the queue 
private class PhotoToLoad { 
    public String url; 
    public ImageView imageView; 

    public PhotoToLoad(String u, ImageView i) { 
     url = u; 
     imageView = i; 
    } 
} 

class PhotosLoader implements Runnable { 
    PhotoToLoad photoToLoad; 

    PhotosLoader(PhotoToLoad photoToLoad) { 
     this.photoToLoad = photoToLoad; 
    } 

    @Override 
    public void run() { 
     try { 
      if (imageViewReused(photoToLoad)) 
       return; 
      Bitmap bmp = getBitmap(photoToLoad.url); 
      memoryCache.put(photoToLoad.url, bmp); 
      if (imageViewReused(photoToLoad)) 
       return; 
      BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad); 
      handler.post(bd); 
     } catch (Throwable th) { 
      th.printStackTrace(); 
     } 
    } 
} 

boolean imageViewReused(PhotoToLoad photoToLoad) { 
    String tag = imageViews.get(photoToLoad.imageView); 
    if (tag == null || !tag.equals(photoToLoad.url)) 
     return true; 
    return false; 
} 

// Used to display bitmap in the UI thread 
class BitmapDisplayer implements Runnable { 
    Bitmap bitmap; 
    PhotoToLoad photoToLoad; 

    public BitmapDisplayer(Bitmap b, PhotoToLoad p) { 
     bitmap = b; 
     photoToLoad = p; 
    } 

    public void run() { 
     if (imageViewReused(photoToLoad)) 
      return; 
     if (bitmap != null) 
      photoToLoad.imageView.setImageBitmap(bitmap); 
     else 
      photoToLoad.imageView.setImageResource(stub_id); 
    } 
} 

public void clearCache() { 
    memoryCache.clear(); 
    fileCache.clear(); 
} 

我覺得我做錯了解析。我無法做實際的解析。任何人都可以解決這個問題嗎？

Answer 1

更新：替換這些行

JSONObject jsonObjThumbnail = jsonobject.getJSONObject("thumbnails"); 
String imgURL = jsonobject.getJSONObject("default").getString("url"); 

到

JSONObject jsonObjThumbnail = jsonObjSnippet.getJSONObject("thumbnails"); 
String imgURL = jsonObjThumbnail.getJSONObject("default").getString("url"); 

爲什麼：縮略圖對象正在片段對象，你在哪裏在主項的對象搜索。

Happy_Coding;