分享实现Android图片选择的两种方式

Android选择图片的两种方式：

第一种：单张选取

通过隐式启动activity，跳转到相册选择一张返回结果

关键代码如下：

发送请求：

private static final int PICTURE = 10086; //requestcode

Intent intent = new Intent();
if (Build.VERSION.SDK_INT < 19) {//因为Android SDK在4.4版本后图片action变化了 所以在这里先判断一下
      intent.setAction(Intent.ACTION_GET_CONTENT);
    } else {
      intent.setAction(Intent.ACTION_OPEN_DOCUMENT);
    }
    intent.setType("image/*");
    intent.addCategory(Intent.CATEGORY_OPENABLE);
startActivityForResult(intent, PICTURE);

接收结果：

@Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (data == null) {
      this.finish();
      return;
    }
    Uri uri = data.getData();
    switch (requestCode) {
      case PICTURE:
        image = FileUtils.getUriPath(this, uri); //（因为4.4以后图片uri发生了变化）通过文件工具类 对uri进行解析得到图片路径
        break;
      default:
        break;
    }
    this.finish();
  }

文件工具类：

public class FileUtils {
  private static final String TAG = "FileUtils";
  private static final boolean DEBUG = false;
  /**
   * 获取可读的文件大小
   */
  public static String getReadableFileSize(int size) {
    final int BYTES_IN_KILOBYTES = 1024;
    final DecimalFormat dec = new DecimalFormat("###.#");
    final String KILOBYTES = " KB";
    final String MEGABYTES = " MB";
    final String GIGABYTES = " GB";
    float fileSize = 0;
    String suffix = KILOBYTES;
    if(size > BYTES_IN_KILOBYTES) {
      fileSize = size / BYTES_IN_KILOBYTES;
      if(fileSize > BYTES_IN_KILOBYTES) {
        fileSize = fileSize / BYTES_IN_KILOBYTES;
        if(fileSize > BYTES_IN_KILOBYTES) {
          fileSize = fileSize / BYTES_IN_KILOBYTES;
          suffix = GIGABYTES;
        } else {
          suffix = MEGABYTES;
        }
      }
    }
    return String.valueOf(dec.format(fileSize) + suffix);
  }
  /**
   * 获取文件的文件名(不包括扩展名)
   */
  public static String getFileNameWithoutExtension(String path) {
    if(path == null) {
      return null;
    }
    int separatorIndex = path.lastIndexOf(File.separator);
    if(separatorIndex < 0) {
      separatorIndex = 0;
    }
    int dotIndex = path.lastIndexOf(".");
    if(dotIndex < 0) {
      dotIndex = path.length();
    } else if(dotIndex < separatorIndex) {
      dotIndex = path.length();
    }
    return path.substring(separatorIndex + 1, dotIndex);
  }
  /**
   * 获取文件名
   */
  public static String getFileName(String path) {
    if(path == null) {
      return null;
    }
    int separatorIndex = path.lastIndexOf(File.separator);
    return (separatorIndex < 0) ? path : path.substring(separatorIndex + 1, path.length());
  }
  /**
   * 获取扩展名
   */
  public static String getExtension(String path) {
    if(path == null) {
      return null;
    }
    int dot = path.lastIndexOf(".");
    if(dot >= 0) {
      return path.substring(dot);
    } else {
      return "";
    }
  }
  public static File getUriFile(Context context, Uri uri) {
    String path = getUriPath(context, uri);
    if(path == null) {
      return null;
    }
    return new File(path);
  }
  public static String getUriPath(Context context, Uri uri) {
    if(uri == null) {
      return null;
    }
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && DocumentsContract.isDocumentUri(context, uri)) {
      if("com.android.externalstorage.documents".equals(uri.getAuthority())) {
        final String docId = DocumentsContract.getDocumentId(uri);
        final String[] split = docId.split(":");
        final String type = split[0];
        if("primary".equalsIgnoreCase(type)) {
          return Environment.getExternalStorageDirectory() + "/" + split[1];
        }
      } else if("com.android.providers.downloads.documents".equals(uri.getAuthority())) {
        final String id = DocumentsContract.getDocumentId(uri);
        final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
        return getDataColumn(context, contentUri, null, null);
      } else if("com.android.providers.media.documents".equals(uri.getAuthority())) {
        final String docId = DocumentsContract.getDocumentId(uri);
        final String[] split = docId.split(":");
        final String type = split[0];
        Uri contentUri = null;
        if("image".equals(type)) {
          contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        } else if("video".equals(type)) {
          contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
        } else if("audio".equals(type)) {
          contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
        }
        final String selection = "_id=?";
        final String[] selectionArgs = new String[] {split[1]};
        return getDataColumn(context, contentUri, selection, selectionArgs);
      }
    } else if("content".equalsIgnoreCase(uri.getScheme())) {
      if("com.google.android.apps.photos.content".equals(uri.getAuthority())) {
        return uri.getLastPathSegment();
      }
      return getDataColumn(context, uri, null, null);
    } else if("file".equalsIgnoreCase(uri.getScheme())) {
      return uri.getPath();
    }
    return null;
  }
  public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = {column};
    try {
      cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
      if(cursor != null && cursor.moveToFirst()) {
        final int column_index = cursor.getColumnIndexOrThrow(column);
        return cursor.getString(column_index);
      }
    } finally {
      if(cursor != null) cursor.close();
    }
    return null;
  }
}

第二种方式 批量选择图片

如果我们需要类似于微信那样的一次选取多张图片，很明显第一种方式是不能满足需求，那么怎么才能批量选取呢？andorid并提供像单张选取似的批量选取的直接方法，所以我们只能自己从数据库中获得。

首先我们要认识一个类mediastore  android中所有的多媒体文件都存储在这个数据库中，例如图片 视频 音频 等等，他通过contentprovider 向其他进程提供数据的接口

想要从mediastore中获得数据，我们可以使用与ContentProvider 对应的ContentResolver

关键代码：

 final String[] projectionPhotos = {
        MediaStore.Images.Media._ID,//每一列的ID 图片的ID
        MediaStore.Images.Media.BUCKET_ID,//图片所在文件夹ID
        MediaStore.Images.Media.BUCKET_DISPLAY_NAME,//图片所在文件夹名称
        MediaStore.Images.Media.DATA,//图片路径
        MediaStore.Images.Media.DATE_TAKEN,//图片创建时间
    };

cursor = MediaStore.Images.Media.query(context.getContentResolver(), MediaStore.Images.Media.EXTERNAL_CONTENT_URI
    , projectionPhotos, "", null, MediaStore.Images.Media.DATE_TAKEN + " DESC");

所有图片都在cursor里了 再从cursor中取出即可