AlbumBusiness.java

package com.eighteengray.procamera.business;


import android.content.ContentResolver;
import android.database.Cursor;
import android.provider.MediaStore;

import com.eighteengray.procamera.bean.ImageFolder;
import com.eighteengray.procamera.model.SystemModel;

import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import rx.Observable;
import rx.android.schedulers.AndroidSchedulers;
import rx.functions.Action1;
import rx.schedulers.Schedulers;


/**
 * 相册相关的业务类，主要作用是处理获取到的Cursor，封装成ImageFolder，然后返回其对应的Observerable
 */
public class AlbumBusiness
{

    //获取ImageFolder的列表
    public static Observable<List<ImageFolder>> getImageFolder(ContentResolver contentResolver)
    {
        final Map<String, Integer> tmpDir = new HashMap<String, Integer>(); //用于防止同一个文件夹的多次扫描
        final List<ImageFolder> imageFolderList = new ArrayList<>();
        SystemModel.getImagesCursor(contentResolver).subscribe(new Action1<Cursor>()
        {
            @Override
            public void call(Cursor cursor)
            {
                if (cursor.moveToFirst())
                {
                    int data = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
                    do
                    {
                        // 获取图片的路径
                        String path = cursor.getString(data);

                        // 获取该图片的父路径名
                        File parentFile = new File(path).getParentFile();
                        if (parentFile == null)
                        {
                            continue;
                        }
                        String dirPath = parentFile.getAbsolutePath();
                        ImageFolder imageFolder = null;
                        if (!tmpDir.containsKey(dirPath))
                        {
                            // 初始化imageFloder
                            imageFolder = new ImageFolder();
                            imageFolder.setFolderDir(dirPath);
                            imageFolder.setFirstImagePath(path);
                            imageFolderList.add(imageFolder);
                            tmpDir.put(dirPath, imageFolderList.indexOf(imageFolder));
                        } else
                        {
                            imageFolder = imageFolderList.get(tmpDir.get(dirPath));
                        }
                        imageFolder.getImagePathList().add(path);
                    } while (cursor.moveToNext());
                }
                cursor.close();
            }
        });
        Observable<List<ImageFolder>> imageFolderListObserverable = Observable.just(imageFolderList).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread());
        return imageFolderListObserverable;
    }



}