将 Youtube Gdata json 解析为 ListView

Question

我一直在尝试在 Android 中找到一个“解析 Youtube Gdata JSON”的工作示例来填充列表视图。

我一直在阅读 this question，除了 4 个错误之外，我几乎可以正常工作。

1. item_title

2. item_subtitle

3. setListAdapter

4. 获取列表视图

   import android.app.Activity;
   import android.os.Bundle;
   import android.util.Log;
   import android.view.Menu;
   import android.view.View;
   import android.widget.AdapterView;
   import android.widget.ListAdapter;
   import android.widget.ListView;
   import android.widget.SimpleAdapter;
   import android.widget.Toast;
   import org.json.JSONArray;
   import org.json.JSONException;
   import org.json.JSONObject;
   import java.util.ArrayList;
   import java.util.HashMap;
   
   public class listview extends Activity {
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.listview_main);
   
   ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
   
   //Get the data (see above)
   JSONObject json = getJSON.getJSONfromURL("https://gdata.youtube.com/feeds/api/videos?q=random&max-results=50&v=2&alt=jsonc");
   
   
   try{
   
   
   
       final JSONArray array = json.getJSONArray("items");
   
       //Loop the Array
       for(int i=0;i < array.length();i++){
   
           HashMap<String, String> map = new HashMap<String, String>();
           JSONObject e = array.getJSONObject(i);
   
           map.put("id",  String.valueOf(i));
           map.put("title", "" + e.getString("title"));
           map.put("viewCount", "Views: " +  e.getString("viewCount"));
           mylist.add(map);
       }
   }catch(JSONException e)        {
       Log.e("log_tag", "Error parsing data " + e.toString());
   }
   
          ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.dubstep,
                  new String[] { "title", "viewCount" },
                  new int[] { R.id.item_title, R.id.item_subtitle });
   
   setListAdapter(adapter);
   
   final ListView lv = getListView();
   //final ListView lv = getListView();
   lv.setTextFilterEnabled(true);
   lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
       public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
           @SuppressWarnings("unchecked")
           HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);
           Toast.makeText(listview.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show();
   
       }
   });
   
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
       // Inflate the menu; this adds items to the action bar if it is present.
       getMenuInflater().inflate(R.menu.listview, menu);
       return true;
       }
   }
   

上面写着"Cannot resolve symbol 'item_title' and 'item_subtitle'
和 "Cannot resolve method 'setListAdapter(android.widget.ListAdapter)'

感谢任何帮助，谢谢！

Answer 1

您的活动类没有扩展ListActivity。因此出现错误 3 和 4

您应该使用AsyncTask 进行网络相关操作。您不能在主 ui 线程上运行网络相关操作。

您应该对图像使用延迟加载。但是对于示例，我使用 ArrayList 的位图作为缩略图。您可能会遇到内存泄漏。所以使用延迟加载。根据您的要求修改以下内容。

例子：

public class MainActivity extends Activity {

    Button b;
    ListView lv;
    ArrayList<String> msg = new ArrayList<String>();
    ArrayList<String> title = new ArrayList<String>();
    ArrayList<Bitmap> thumb = new ArrayList<Bitmap>();
    ProgressDialog pd;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lv= (ListView) findViewById(R.id.lv);
        pd = new ProgressDialog(MainActivity.this);
        pd.setTitle("Loading..");
        b= (Button) findViewById(R.id.button1);
        b.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                new TheTask().execute();
            }

       });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    public void getData()
    {
        HttpClient httpclient = new DefaultHttpClient();
        httpclient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1);
        HttpGet request = new HttpGet("https://gdata.youtube.com/feeds/api/videos?q=random&max-results=50&v=2&alt=jsonc");
        // HttpGet request = new HttpGet("http://gdata.youtube.com/feeds/api/users/mbbangalore/uploads?v=2&alt=jsonc");     
        try
        {
        HttpResponse response = httpclient.execute(request);
        HttpEntity resEntity = response.getEntity();
        String _response=EntityUtils.toString(resEntity); // content will be consume only once

        JSONObject json = new JSONObject(_response);

        JSONArray jsonArray = json.getJSONObject("data").getJSONArray("items");
        for (int i = 0; i < jsonArray.length(); i++) {
            JSONObject jsonObject = jsonArray.getJSONObject(i);

            String title1 = jsonObject.getString("title");
            title.add(title1);
            String thumbUrl = jsonObject.getJSONObject("thumbnail").getString("sqDefault");
            URL url1 = new URL(thumbUrl);
            Bitmap bmp = BitmapFactory.decodeStream(url1.openConnection().getInputStream());
            thumb.add(bmp);
            String url;
            try {

                url = jsonObject.getJSONObject("player").getString("default");
                msg.add(url);
            } catch (JSONException ignore) {
            }
        }
        } 
        catch(Exception e1)
            {
                e1.printStackTrace();
            }

        httpclient.getConnectionManager().shutdown();
    }
  class TheTask extends AsyncTask<Void,Void,Void>
  {

    @Override
    protected void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        pd.dismiss();
        YouTubeAdapter you = new YouTubeAdapter(MainActivity.this,msg,title,thumb);
        lv.setAdapter(you);
    }

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        pd.show();
    }

    @Override
    protected Void doInBackground(Void... params) {
        // TODO Auto-generated method stub
        getData();
        return null;
    }

  }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ListView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/lv"
        android:layout_above="@+id/button1"
       />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:text="Button" />

</RelativeLayout>

YouTube 适配器

public class YouTubeAdapter extends BaseAdapter{

    Context mContext;
    Intent intent;
    LayoutInflater mInflater;
    ArrayList<String> mVideo= new ArrayList<String>();
    ArrayList<String> mTitle= new ArrayList<String>();
    ArrayList<Bitmap> mThumb= new ArrayList<Bitmap>();

    public YouTubeAdapter(Context context,ArrayList<String> a,ArrayList title,ArrayList thumb)  {
        mContext=context;
        mVideo=a;   
        mTitle = title;
        mThumb= thumb;
        mInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return mVideo.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public View getView(final int position, View arg1, ViewGroup arg2) {
        ViewHolder vh;

        if(arg1==null)
        {
            arg1=mInflater.inflate(R.layout.video, null);
            vh= new ViewHolder();
            vh.tv=(TextView)arg1.findViewById(R.id.tvv);
            vh.iv=(ImageView)arg1.findViewById(R.id.ivv);
            arg1.setTag(vh);
        }
        else
        {
            vh= (ViewHolder)arg1.getTag();
        }
        vh.tv.setText(mTitle.get(position));
        vh.iv.setImageBitmap(mThumb.get(position));
        return arg1;
    }

    static class ViewHolder
    {
        TextView tv;
        ImageView iv;
    }   
}

video.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
     >

    <TextView
        android:id="@+id/tvv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:textColor="#000000"
        android:textSize="13dp" />

    <ImageView
        android:id="@+id/ivv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

</LinearLayout>

快照