安卓获取相册并且展示

获取相册主要原理就是通过

ContentResolver

访问系统数据库表，里面有文件的信息，在同一个文件夹的，就表示在一个相册，并且归结为一类

package com.example.administrator.iphoto.helper;

import android.content.ContentResolver;
import android.content.Context;
import android.database.Cursor;
import android.os.AsyncTask;
import android.provider.MediaStore.Audio.Albums;
import android.provider.MediaStore.Images.Media;
import android.provider.MediaStore.Images.Thumbnails;
import android.util.Log;

import com.example.administrator.iphoto.model.ImageBucket;
import com.example.administrator.iphoto.model.ImageItem;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class AlbumHelper extends AsyncTask, Object, Object> {

    final String TAG = getClass().getSimpleName();
    Context context;
    ContentResolver cr;
    // 缩略图列表
    HashMap, String> thumbnailList = new HashMap, String>();
    // 专辑列表Q
    List, String>> albumList = new ArrayList, String>>();
    HashMap, ImageBucket> bucketList = new HashMap, ImageBucket>();
    private GetAlbumList getAlbumList;

    private AlbumHelper() {}
    public static AlbumHelper getHelper() {
        AlbumHelper instance = new AlbumHelper();
        return instance;
    }

    /**
     * 初始化
     * @param context
     */
    public void init(Context context) {
        if (this.context == null) {
            this.context = context;
            cr = context.getContentResolver();
        }
    }

    /**
     * 得到缩略图
     */
    private void getThumbnail() {
        String[] projection = { Thumbnails._ID, Thumbnails.IMAGE_ID,
                Thumbnails.DATA};
        Cursor cursor1 = Thumbnails.queryMiniThumbnails(cr, Thumbnails.EXTERNAL_CONTENT_URI,
                Thumbnails.MINI_KIND, projection);
        getThumbnailColumnData(cursor1);
        cursor1.close();
    }

    /**
     * 从数据库中得到缩略图
     * @param cur
     */
    private void getThumbnailColumnData(Cursor cur) {
        if (cur.moveToFirst()) {
            int image_id;
            String image_path;
            int image_idColumn = cur.getColumnIndex(Thumbnails.IMAGE_ID);
            int dataColumn = cur.getColumnIndex(Thumbnails.DATA);
            do {
                image_id = cur.getInt(image_idColumn);
                image_path = cur.getString(dataColumn);
                thumbnailList.put("" + image_id, image_path);
            } while (cur.moveToNext());
        }
    }

    /**
     * 得到原图-n
     */
    void getAlbum() {
        String[] projection = { Albums._ID, Albums.ALBUM, Albums.ALBUM_ART,
                Albums.ALBUM_KEY, Albums.ARTIST, Albums.NUMBER_OF_SONGS };
        Cursor cursor1 = cr.query(Albums.EXTERNAL_CONTENT_URI, projection, null,
                null, Albums.ALBUM_ID+" desc");
        getAlbumColumnData(cursor1);
        cursor1.close();
    }

    /**
     * 从本地数据库中得到原图
     * @param cur
     */
    private void getAlbumColumnData(Cursor cur) {
        if (cur.moveToFirst()) {
            int _id;
            String album;
            String albumArt;
            String albumKey;
            String artist;
            int numOfSongs;
            int _idColumn = cur.getColumnIndex(Albums._ID);
            int albumColumn = cur.getColumnIndex(Albums.ALBUM);
            int albumArtColumn = cur.getColumnIndex(Albums.ALBUM_ART);
            int albumKeyColumn = cur.getColumnIndex(Albums.ALBUM_KEY);
            int artistColumn = cur.getColumnIndex(Albums.ARTIST);
            int numOfSongsColumn = cur.getColumnIndex(Albums.NUMBER_OF_SONGS);
            do {
                _id = cur.getInt(_idColumn);
                album = cur.getString(albumColumn);
                albumArt = cur.getString(albumArtColumn);
                albumKey = cur.getString(albumKeyColumn);
                artist = cur.getString(artistColumn);
                numOfSongs = cur.getInt(numOfSongsColumn);
                HashMap, String> hash = new HashMap, String>();
                hash.put("_id", _id + "");
                hash.put("album", album);
                hash.put("albumArt", albumArt);
                hash.put("albumKey", albumKey);
                hash.put("artist", artist);
                hash.put("numOfSongs", numOfSongs + "");
                albumList.add(hash);
            } while (cur.moveToNext());
        }
    }

    /**
     * 是否创建了图片集
     */
    boolean hasBuildImagesBucketList = false;
    /**
     * 得到图片集
     */
    void buildImagesBucketList() {
        // 构造缩略图索引
        getThumbnail();
        // 构造相册索引
        String columns[] = new String[] { Media._ID, Media.BUCKET_ID,
                Media.PICASA_ID, Media.DATA, Media.DISPLAY_NAME, Media.TITLE,
                Media.SIZE, Media.BUCKET_DISPLAY_NAME };
        // 得到一个游标
        Cursor cur = cr.query(Media.EXTERNAL_CONTENT_URI, columns, null, null,
                Media.DATE_MODIFIED+" desc");
        if (cur.moveToFirst()) {
            // 获取指定列的索引,注意Media是Image Media,获取到的当然是图片资源
            int photoIDIndex = cur.getColumnIndexOrThrow(Media._ID);//文件ID
            int photoPathIndex = cur.getColumnIndexOrThrow(Media.DATA);//文件路径
            int bucketDisplayNameIndex = cur.getColumnIndexOrThrow(Media.BUCKET_DISPLAY_NAME);//文件所在文件夹名称
            int bucketIdIndex = cur.getColumnIndexOrThrow(Media.BUCKET_ID);//文件所在文件夹ID
            /**
             * Description:这里增加了一个判断：判断照片的名字是否合法，例如.jpg .png    图片名字是不合法的，直接过滤掉
             */
            String aa = cur.getString(photoPathIndex);
            do {
                    String _id = cur.getString(photoIDIndex);
                    String path = cur.getString(photoPathIndex);
                    String bucketName = cur.getString(bucketDisplayNameIndex);
                    String bucketId = cur.getString(bucketIdIndex);
                    ImageBucket bucket = bucketList.get(bucketId);
                    if (bucket == null) {
                        bucket = new ImageBucket();
                        bucketList.put(bucketId, bucket);
                        bucket.imageList = new ArrayList();
                        bucket.bucketName = bucketName;
                    }
                    bucket.count++;
                    ImageItem imageItem = new ImageItem();
                    imageItem.setImageId(_id);
                    imageItem.setImagePath(path);
//             imageItem.setThumbnailPath(thumbnailList.get(_id));
                    bucket.imageList.add(imageItem);
                    Log.i(TAG, "PhotoUpAlbumHelper类中 的——》path="+thumbnailList.get(_id));
            } while (cur.moveToNext());
        }
        cur.close();
        hasBuildImagesBucketList = true;
    }

    /**
     * 得到图片集
     * @param refresh
     * @return
     */
    public List getImagesBucketList(boolean refresh) {
        if (refresh || (!refresh && !hasBuildImagesBucketList)) {
            buildImagesBucketList();
        }
        List tmpList = new ArrayList();
        Iterator, ImageBucket>> itr = bucketList.entrySet().iterator();
        while (itr.hasNext()) {
            Map.Entry, ImageBucket> entry = (Map.Entry, ImageBucket>) itr
                    .next();
            tmpList.add(entry.getValue());
        }
        return tmpList;
    }

    /**
     * 得到原始图像路径
     * @param image_id
     * @return
     */
    String getOriginalImagePath(String image_id) {
        String path = null;
        Log.i(TAG, "---(^o^)----" + image_id);
        String[] projection = { Media._ID, Media.DATA };
        Cursor cursor = cr.query(Media.EXTERNAL_CONTENT_URI, projection,
                Media._ID + "=" + image_id, null, Media.DATE_MODIFIED+" desc");
        if (cursor != null) {
            cursor.moveToFirst();
            path = cursor.getString(cursor.getColumnIndex(Media.DATA));
        }
        return path;
    }
    public void destoryList()
    {
        thumbnailList.clear();
        thumbnailList = null;
        albumList.clear();
        albumList = null;
        bucketList.clear();
        bucketList = null;
    }

    public void setGetAlbumList(GetAlbumList getAlbumList) {
        this.getAlbumList = getAlbumList;
    }

    public interface GetAlbumList{
        public void getAlbumList(List list);
    }

    @Override
    protected Object doInBackground(Object... params) {
        return getImagesBucketList((Boolean)(params[0]));
    }
    @SuppressWarnings("unchecked")
    @Override
    protected void onPostExecute(Object result) {
        super.onPostExecute(result);
        getAlbumList.getAlbumList((List)result);
    }

}

参考地址:http://blog.csdn.net/u010156024/article/details/44136543