public class GalleryHelper{

    private Activity mActivity;

    public GalleryHelper(Activity activity) {
      mActivity = new WeakReference<>(activity).get();
    }
  }

public final class FolderEntity {

  private int num;
  private String name;
  private List<String> paths = new ArrayList<>();

  public int getNum() {
    return paths.size();
  }

  public List<String> getPaths() {
    return paths;
  }

  public void setName(String name) {
    this.name = name;
  }
}

  mActivity.getLoaderManager().initLoader(0, null, new LoaderManager.LoaderCallbacks<Cursor>() {
      @Override
      public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
      }

      @Override
      public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
      }

      @Override
      public void onLoaderReset(Loader<Cursor> loader) {

      }
    });

  public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
     return new CursorLoader(mActivity,
         MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
         new String[]{MediaStore.Images.Media.DATA},
         MediaStore.Images.Media.MIME_TYPE + "=? or "
             + MediaStore.Images.Media.MIME_TYPE + "=?",
         new String[]{"image/jpeg", "image/png"},
         MediaStore.Images.Media.DATE_ADDED + " DESC");
   }

  public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
     HashMap<String, FolderEntity> folderEntityHashMap = new HashMap<String, FolderEntity>();
      if (cursor != null) {
        while (cursor.moveToNext()) {
          //图片路径
          String path = cursor.getString(
          cursor.getColumnIndex(MediaStore.Images.Media.DATA));

          // 路径不存在或者文件不存在就跳过
          File file = new File(path);
          if (TextUtils.isEmpty(path) || !file.exists()) {
            continue;
          }
          String folerPath = file.getParent();
          FolderEntity folderEntity;
          if (folderEntityHashMap.containsKey(folerPath)) {
            folderEntity = folderEntityHashMap.get(folerPath);
          } else {
            folderEntity = new FolderEntity();
            folderEntityHashMap.put(file.getParentFile().getName(), folderEntity);
          }
          folderEntity.getPaths().add(path);
        }
        cursor.close();
      }

    }

    private ArrayList<FolderEntity> map2List(HashMap<String, FolderEntity> mediaBeanMap) {
      Iterator<FolderEntity> iterator = mediaBeanMap.values().iterator();
      ArrayList<FolderEntity> list = new ArrayList<FolderEntity>();
      while (iterator.hasNext()) {
        list.add(iterator.next());
      }
      Collections.sort(list, new Comparator<FolderEntity>() {
        @Override
        public int compare(FolderEntity lhs, FolderEntity rhs) {
          return lhs.getNum() > rhs.getNum() ? 1 : -1;
        }
      });
      return list;
    }

  public interface GalleryCallback {
    void complete(List<FolderEntity> list);
  }

  callback.complete(map2List(folderEntityHashMap));

  File imageStoreDir = new File(Environment.getExternalStorageDirectory(),
      "/DCIM/" + mActivity.getResources().getString(R.string.app_name));
  if (!imageStoreDir.exists()) {
    imageStoreDir.mkdir();
  }
  Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
  if (captureIntent.resolveActivity(mActivity.getPackageManager()) != null) {
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss", Locale.CHINA);
    String filename = String.format("IMG%s", dateFormat.format(new Date()));
    imagePath = new File(imageStoreDir, filename).getAbsolutePath();
    captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(imagePath)));
    mActivity.startActivityForResult(new Intent(
        MediaStore.ACTION_IMAGE_CAPTURE), REQUEST_CODE);
  }

  public interface CameraCallback {
    void complete(String path);
  }

  public void onActivityResult(int requestCode, int resultCode) {
    if (Activity.RESULT_OK == resultCode && REQUEST_CODE == requestCode) {
      if (cameraCallback != null) {
        cameraCallback.complete(imagePath);
      }
    }
  }

  galleryHelper = new GalleryHelper(this);
    galleryHelper.loadImages(new GalleryHelper.GalleryCallback() {
      @Override
      public void complete(List<FolderEntity> list) {
        //加载本地图片返回结果
      }
    });

 findViewById(R.id.btn_camera).setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View v) {
       galleryHelper.openCamera(new GalleryHelper.CameraCallback() {
         @Override
         public void complete(String path) {
         //拍照返回结果
         }
       });
     }
   });

  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    //使用拍照，必须接收Activity的onActivityResult方法
    galleryHelper.onActivityResult(requestCode, resultCode);
  }

  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  <uses-permission android:name="android.permission.CAMERA" />
  <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />