访问共享存储空间

• 访问媒体文件

  • 直接构造路径

    private void testShareMedia() {
    //获取目录：/storage/emulated/0/
    File rootFile = Environment.getExternalStorageDirectory();
    String imagePath = rootFile.getAbsolutePath() + File.separator + Environment.DIRECTORY_PICTURES + File.separator + "myPic.png";
    Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
    }
    

  • 通过 MediaStore 获取路径

    private void getImagePath(Context context) {
    ContentResolver contentResolver = context.getContentResolver();
    Cursor cursor = contentResolver.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
    while(cursor.moveToNext()) {
      String imagePath = cursor.getString(cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA));
      Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
      break;
    }
    }
    

  • 通过 MediaStore 获取 Uri

    private void getImagePath(Context context) {
    ContentResolver contentResolver = context.getContentResolver();
    Cursor cursor = contentResolver.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
    while(cursor.moveToNext()) {
      //获取唯一的id
      long id = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.MediaColumns._ID));
      //通过id构造Uri
      Uri uri = ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, id);
      openUri(uri);
      break;
    }
    }
    

• 文档/其它文件

  • 直接构造路径

  • 通过 SAF 获取 Uri
    Storage Access Framework 简称SAF：存储访问框架。相当于系统内置了文件选择器，通过它可以拿到想要访问的文件信息。

    private void startSAF() {
        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        //选择图片
        intent.setType("image/jpeg");
        startActivityForResult(intent, 100);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == 100) {
            //选中返回的图片封装在uri里
            Uri uri = data.getData();
            openUri(uri);
        }
    }

    private void openUri(Uri uri) {
        try {
            //从uri构造输入流
            InputStream fis = getContentResolver().openInputStream(uri);
            Bitmap bitmap = BitmapFactory.decodeStream(fis);
        } catch (Exception e) {

        }
    }

参考链接
https://jishuin.proginn.com/p/763bfbd60de7