安卓学习之检索MediaStore中的Video和其对应的缩略图信息

和Image，Audio一样，在Android中，Video信息也被MediaStore管理着。

 

和每个视频对应的有其一个缩略图，这个缩略图往往是其第一帧的图像。

 

下面看代码：

[java] view plaincopyprint?package demo.camera;  import java.util.ArrayList;  import java.util.List;  import android.app.ListActivity;  import android.content.Context;  import android.database.Cursor;  import android.net.Uri;  import android.os.Bundle;  import android.provider.MediaStore;  import android.view.LayoutInflater;  import android.view.View;  import android.view.ViewGroup;  import android.widget.BaseAdapter;  import android.widget.ImageView;  import android.widget.TextView;  /**  * 本实例，我们将通过检索SDCard上的Video信息  * 在MediaStore中，MediaStore.Video.Media中就有Video相关信息，  * 同时MediaStore.Video.Thumbnails中含有各个video对应的缩略图信息  *   * @author Administrator  *  */  public class AdvancedVideoDemo extends ListActivity {            private Cursor cursor;            public void onCreate(Bundle savedInstanceState){          super.onCreate(savedInstanceState);          setContentView(R.layout.video_advanced);                    init();      }                  private void init(){          String[] thumbColumns = new String[]{                  MediaStore.Video.Thumbnails.DATA,                  MediaStore.Video.Thumbnails.VIDEO_ID          };                    String[] mediaColumns = new String[]{                  MediaStore.Video.Media.DATA,                  MediaStore.Video.Media._ID,                  MediaStore.Video.Media.TITLE,                  MediaStore.Video.Media.MIME_TYPE          };                    //首先检索SDcard上所有的video           cursor = this.managedQuery(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, mediaColumns, null, null, null);                    ArrayList<VideoInfo> videoList = new ArrayList<AdvancedVideoDemo.VideoInfo>();                    if(cursor.moveToFirst()){              do{                  VideoInfo info = new VideoInfo();                                    info.filePath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA));                  info.mimeType = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.MIME_TYPE));                  info.title = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.TITLE));                                    //获取当前Video对应的Id，然后根据该ID获取其Thumb                   int id = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));                  String selection = MediaStore.Video.Thumbnails.VIDEO_ID +"=?";                  String[] selectionArgs = new String[]{                          id+""                  };                  Cursor thumbCursor = this.managedQuery(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI, thumbColumns, selection, selectionArgs, null);                                    if(thumbCursor.moveToFirst()){                      info.thumbPath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Thumbnails.DATA));                                        }                                    //然后将其加入到videoList                   videoList.add(info);                                }while(cursor.moveToNext());          }                    //然后需要设置ListView的Adapter了，使用我们自定义的Adatper           VideoAdapter adapter = new VideoAdapter(this, videoList);          this.getListView().setAdapter(adapter);      }            static class VideoInfo{          String filePath;          String mimeType;          String thumbPath;          String title;      }            /**      * 定义一个Adapter来显示缩略图和视频title信息      * @author Administrator      *      */      static class VideoAdapter extends BaseAdapter{                    private Context context;          private List<VideoInfo> videoItems;                    public VideoAdapter(Context context, List<VideoInfo> data){              this.context = context;              this.videoItems = data;          }          @Override          public int getCount() {              // TODO Auto-generated method stub               return videoItems.size();          }          @Override          public Object getItem(int p) {              // TODO Auto-generated method stub               return videoItems.get(p);          }          @Override          public long getItemId(int p) {              // TODO Auto-generated method stub               return p;          }          @Override          public View getView(int position, View convertView, ViewGroup parent) {              ViewHolder holder = null;              if(convertView == null){                  holder = new ViewHolder();                  convertView = LayoutInflater.from(context).inflate(R.layout.video_item, null);                  holder.thumbImage = (ImageView)convertView.findViewById(R.id.thumb_image);                  holder.titleText = (TextView)convertView.findViewById(R.id.video_title);                  convertView.setTag(holder);              }else{                  holder = (ViewHolder)convertView.getTag();              }                            //显示信息               holder.titleText.setText(videoItems.get(position).title);              if(videoItems.get(position).thumbPath != null){                  holder.thumbImage.setImageURI(Uri.parse(videoItems.get(position).thumbPath));              }                            return convertView;          }                    class ViewHolder{              ImageView thumbImage;              TextView titleText;          }                }  }