Blob Row 太大太适合 Android

Question

保存到 SQLite 时如何限制图像的大小？当我检索我认为没有从 SQLite 获得大大小的 blob 图像时出现此错误。但是，我尝试在SELECT id,cash_card,hh_number,cc_image FROM CgList limit 500 这样的查询中设置限制 500，但结果是一样的，它使我的应用程序崩溃。

简而言之，有什么办法可以减少图片插入SQLite数据库时的文件大小？

错误

android.database.sqlite.SQLiteBlobTooBigException：行太大而无法容纳 进入 CursorWindow requiredPos=0, totalRows=4

插入数据和blob

 public void insertData(String cash_card, String hh_number,String series_number ,byte[] cc_image,byte[] id_image){
    SQLiteDatabase database = getWritableDatabase();
    String sql = "INSERT INTO CgList VALUES (NULL,?, ?, ?, ?, ?)";
    SQLiteStatement statement = database.compileStatement(sql);
    statement.clearBindings();

    statement.bindString(1, cash_card);
    statement.bindString(2, hh_number);
    statement.bindString(3, series_number);
    statement.bindBlob(4, cc_image);
    statement.bindBlob(5, id_image);
    statement.executeInsert();
}

获取数据

  Cursor cursor = ScannedDetails.sqLiteHelper.getData("SELECT id,cash_card,hh_number,cc_image FROM CgList");
    list.clear();
    while (cursor.moveToNext()) {   // the error is here
        int id = cursor.getInt(0);
        String name = cursor.getString(1);
        String price = cursor.getString(2);
        byte[] image = cursor.getBlob(3);

        list.add(new Inventory(name, price, image, id));
    }
    adapter.notifyDataSetChanged();

当我点击按钮保存到 SQLite 时

    btnSubmit.setOnClickListener( new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            sqLiteHelper.insertData(
                    edtCashCard.getText().toString().trim(),
                    edtHhnumber.getText().toString().trim(),
                    edtSeriesno.getText().toString().trim(),
                    imageViewToByte(mPreviewCashcard),
                    imageViewToByte(mPreview4PsId)
            );
        }
    });

将图像转换为字节

 public static byte[] imageViewToByte(ImageView image) {
   Bitmap bitmap = ((BitmapDrawable)image.getDrawable()).getBitmap();
   ByteArrayOutputStream stream = new ByteArrayOutputStream();
   bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
   byte[] byteArray = stream.toByteArray();
   return byteArray;
 }

更新

我认为这是捕获提供更大尺寸的图像时的问题，我需要这个，因为在捕获图像后，我想出于某种目的裁剪图像，但我想将实际捕获而不是裁剪的图像显示给另一个活动

 private void pickCamera() {
    ContentValues values = new ContentValues();
    values.put(MediaStore.Images.Media.TITLE, "NewPic");
    values.put(MediaStore.Images.Media.DESCRIPTION, "Image to Text");
    image_uri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,values);
    Intent cameraIntent = new Intent (MediaStore.ACTION_IMAGE_CAPTURE);
    cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, image_uri);
    startActivityForResult(cameraIntent, IMAGE_PICK_CAMERA_CODE);
}

OnActivityResult

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK){
        if (requestCode == IMAGE_PICK_GALLER_CODE){
            CropImage.activity(data.getData()).setGuidelines(CropImageView.Guidelines.ON).start(this);
        }
        if (requestCode == IMAGE_PICK_CAMERA_CODE){

            CropImage.activity(image_uri).setGuidelines(CropImageView.Guidelines.ON).start(this);
        }
    }
    if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE){
        CropImage.ActivityResult result = CropImage.getActivityResult(data);
        if(resultCode ==RESULT_OK){
            Uri resultUri = result.getUri();
            resultUri.getPath();
            mPreviewIv.setImageURI(resultUri);
            BitmapDrawable bitmapDrawable = (BitmapDrawable)mPreviewIv.getDrawable();
            Bitmap bitmap = bitmapDrawable.getBitmap();
            TextRecognizer recognizer = new TextRecognizer.Builder(getApplicationContext()).build();

            if(!recognizer.isOperational()){
                Toast.makeText(this,"Error",Toast.LENGTH_SHORT).show();
            }
            else{
                Frame frame = new Frame.Builder().setBitmap(bitmap).build();
                SparseArray<TextBlock> items = recognizer.detect(frame);
                StringBuilder sb = new StringBuilder();

                for (int i = 0; i<items.size(); i++){
                    TextBlock myItem = items.valueAt(i);
                    sb.append(myItem.getValue());
                    sb.append("\n");
                }
                
                Intent i = new Intent(MainActivity.this, ScannedDetails.class);   
                //camera
                i.putExtra("CashCardImage",image_uri.toString());  //This data pass to another activity
                startActivity(i);
            }
        }
    }
}

检索到另一个活动

Bundle extras = getIntent().getExtras();
   String resultUri = extras.getString("CashCardImage");
   Uri myUri = Uri.parse(resultUri);
   mPreviewCashCard.setImageURI(myUri);

我在保存到 SQLITE 时尝试的另一个大小并不大，它只是 KIB，我认为问题出在第一个 PickCamera 但这些代码需要裁剪图像

 private void pickCamera() {
   Intent intent = new Intent(ScannedDetails.this, InventoryList.class);
   startActivity(intent);
   }

Answer 1

但是，我尝试在查询中设置限制 500，例如 SELECT id,cash_card,hh_number,cc_image FROM CgList limit 500

LIMIT 限制返回的行数，不限制行的大小。

问题是单行超出了光标使用的缓存/缓冲区 (CursorWindow) 的容量。插入所述行/行时，此限制不适用。

典型的解决方案是不存储图像，而是存储参考，例如文件路径，然后可以从中检索图像（或其他大型项目）。

Here's an example that stores images less than a set size (100k in the example) as a blob and those larger as files in data/data/myimages, which could be another solution.

可以将大图像分解为数据块并存储/检索。 Here's an example of doing that.

Answer 2

不要将图像直接存储在数据库中。相反，将图像保存到文件或网络服务器。然后在数据库中存储图像的文件路径或 URL。