如何掃描出android系統媒體庫中視頻文件

android系統啓動時會去掃描系統文件，並將系統支持的視頻文件（mp4,3gp,wmv）掃描到媒體庫（MediaStore）中，下面代碼演示如何得到這些文件的信息：

public static List<VideoInfo> sysVideoList = null;// 視頻信息集合
sysVideoList = new ArrayList<VideoInfo>();
setVideoList();

	private void setVideoList() {
		// MediaStore.Video.Thumbnails.DATA:視頻縮略圖的文件路徑
		String[] thumbColumns = { MediaStore.Video.Thumbnails.DATA,
				MediaStore.Video.Thumbnails.VIDEO_ID };

		// MediaStore.Video.Media.DATA：視頻文件路徑；
		// MediaStore.Video.Media.DISPLAY_NAME : 視頻文件名，如 testVideo.mp4
		// MediaStore.Video.Media.TITLE: 視頻標題 : testVideo
		String[] mediaColumns = { MediaStore.Video.Media._ID,
				MediaStore.Video.Media.DATA, MediaStore.Video.Media.TITLE,
				MediaStore.Video.Media.MIME_TYPE,
				MediaStore.Video.Media.DISPLAY_NAME };

		cursor = managedQuery(MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
				mediaColumns, null, null, null);
		
		if(cursor==null){
			Toast.makeText(SystemVideoChooseActivity.this, "沒有找到可播放視頻文件", 1).show();
			return;
		}
		if (cursor.moveToFirst()) {
			do {
				VideoInfo info = new VideoInfo();
				int id = cursor.getInt(cursor
						.getColumnIndex(MediaStore.Video.Media._ID));
				Cursor thumbCursor = managedQuery(
						MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI,
						thumbColumns, MediaStore.Video.Thumbnails.VIDEO_ID
								+ "=" + id, null, null);
				if (thumbCursor.moveToFirst()) {
					info.setThumbPath(thumbCursor.getString(thumbCursor
							.getColumnIndex(MediaStore.Video.Thumbnails.DATA)));
				}
				info.setPath(cursor.getString(cursor
						.getColumnIndexOrThrow(MediaStore.Video.Media.DATA)));
				info.setTitle(cursor.getString(cursor
						.getColumnIndexOrThrow(MediaStore.Video.Media.TITLE)));
				
				info.setDisplayName(cursor.getString(cursor
						.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME)));
				LogUtil.log(TAG, "DisplayName:"+info.getDisplayName());
				info.setMimeType(cursor
						.getString(cursor
								.getColumnIndexOrThrow(MediaStore.Video.Media.MIME_TYPE)));
				
				sysVideoList.add(info);
			} while (cursor.moveToNext());
		}
	}

有一點須要注意的是：系統的媒體庫並不會在咱們添加視頻文件後自動更新，咱們如何去手動掃描媒體庫，或者重啓系統才能從媒體庫中獲得更新的視頻文件：

sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://"  
                + Environment.getExternalStorageDirectory())));