android - 使用 YouTube 数据 API 的 YouTube ImageView

Question

我正在使用 YouTube API 开发应用程序。我正在尝试显示视频标题和视频图像。

我可以显示视频标题，但我无法查看任何图像。

我正在尝试很多事情来解决，但每次我都失败了。现在我看到一个有错误的空白页。我发现这是什么类型的错误，但我无法解决。

这是我的代码

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();
    }
}

这是我看到的错误

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

这是我的图片加载器类..

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();
}

我想我做错了解析。我不能做实际的解析。有人能解决这个问题吗？

Answer 1

更新:替换这些行

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");

原因:thumbnails 对象在 snippet 对象下，您在其中搜索主要项目对象。