将 Android 图像位图更新为 SQLite Blob

Question

我试图找出我在哪里出错，无论是编码还是逻辑缺陷，我创建了一个食谱应用程序，它需要几个字符串和一个图像，所有数据都保存到数据库中，在主屏幕上我得到一个列表来自数据库的食谱。

主屏幕

添加/编辑屏幕

创建或添加新数据按预期工作，所有数据都已保存。问题是除了图像之外的所有内容都可以更新，一旦保存，任何第二次尝试似乎都不会影响图像，图像保持不变。

核心原则是将数据设置到视图（当用户启动活动 onCreate 或恢复活动 onResume 时）并从视图中获取数据（当用户离开 onPause 和 onSaveInstanceState 以防更新时）

代码

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add_edit);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                enableEdit();
                fab.hide();
            }
        });
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        recipeDAOImp = new RecipeDAOImp(this);
        recipeDAOImp.open();
        findViews();

        rowId = (savedInstanceState == null) ? null :
                (Long) savedInstanceState.getSerializable(RecipeDAOImp.KEY_ID);
        if (rowId == null) {
            Bundle extras = getIntent().getExtras();
            rowId = extras != null ? extras.getLong(RecipeDAOImp.KEY_ID)
                    : null;
        }
        populateData();
        disableEdit();
    }

    private void findViews() {
       // Finds Views and Set onClick to imageButton
    }


    private void disableEdit() {
        // Disable Views
    }

    private void enableEdit() {
        // Enables Views
    }

    private void populateData() {
        // If rowId is available then user is trying to Edit Recipe
        if (rowId != null) {
            setTitle("Edit Recipe");
            Recipe recipe = new Recipe(rowId);
            Cursor cursor = recipeDAOImp.getRecipe(recipe);
            startManagingCursor(cursor);
            title.setText(cursor.getString(
                    cursor.getColumnIndexOrThrow(RecipeDAOImp.KEY_TITLE)));
            ingredients.setText(cursor.getString(
                    cursor.getColumnIndexOrThrow(RecipeDAOImp.KEY_INGREDIENTS)));

            steps.setText(cursor.getString(
                    cursor.getColumnIndexOrThrow(RecipeDAOImp.KEY_STEPS)));

            category.setText(cursor.getString(
                    cursor.getColumnIndexOrThrow(RecipeDAOImp.KEY_CATEGORY)));

            BitmapDrawable bitmapDrawable = new BitmapDrawable(getResources(), DbBitmapUtility.getImage(cursor.getBlob(
                    cursor.getColumnIndexOrThrow(RecipeDAOImp.KEY_IMAGE))));
            image.setBackground(bitmapDrawable);
        // Else user is Adding a new Recipe
        } else {
            fab.hide();
            setTitle("Add Recipe");
            enableEdit();
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        saveState();
        outState.putSerializable(RecipeDAOImp.KEY_ID, rowId);
    }

    @Override
    protected void onPause() {
        super.onPause();
        saveState();
    }

    @Override
    protected void onResume() {
        super.onResume();
        populateData();
    }

    private void saveState() {
        // Get the values from the views
        String titleString = title.getText().toString();
        String ingredientString = ingredients.getText().toString();
        String stepsString = steps.getText().toString();
        String categoryString = category.getText().toString();
        // Get the image from imageButton
        Drawable drawable = image.getBackground();
        Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
        byte[] imageData = DbBitmapUtility.getBytes(bitmap);
        // Just to clarify image is never null as the backround is a camre image
        if (titleString.equals(null) || "".equals(titleString) || ingredientString.equals(null) || "".equals(ingredientString) || stepsString.equals(null) || "".equals(stepsString) || categoryString.equals(null) || "".equals(categoryString) || imageData.equals(null) || "".equals(imageData)) {
            Toast.makeText(this, "No Data Saved", Toast.LENGTH_SHORT).show();
        } else {
            Recipe recipe = new Recipe(titleString, ingredientString, stepsString, categoryString, imageData);
            // If rowId is not Available then user is Creating a new Recipe
            if (rowId == null) {
                long id = recipeDAOImp.createRecipe(recipe);
                if (id > 0) {
                    rowId = id;
                }
            } else {
                recipe.setId(rowId);
                recipeDAOImp.updateRecipe(recipe);
            }
        }
    }

    @Override
    public void onClick(View view) {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
            Bundle extras = data.getExtras();
            Bitmap imageBitmap = (Bitmap) extras.get("data");
            // Set the imageButton
            BitmapDrawable bitmapDrawable = new BitmapDrawable(getResources(), imageBitmap);
            image.setBackground(bitmapDrawable);
        }
    }
}

DAO

@Override
public boolean updateRecipe(Recipe recipe) {
    ContentValues contentValues = new ContentValues();
    contentValues.put(KEY_TITLE, recipe.getTitle());
    contentValues.put(KEY_INGREDIENTS, recipe.getIngredients());
    contentValues.put(KEY_STEPS, recipe.getSteps());
    contentValues.put(KEY_CATEGORY, recipe.getCategory());
    contentValues.put(KEY_IMAGE, recipe.getImage());
    return sqLiteDatabase.update(DATABASE_TABLE, contentValues, KEY_ID + "=" + recipe.getId(), null) > 0;
}

我可以更新字符串数据但保存后无法真正更新图像，这可能是什么问题？

Answer 1

经过大量研究和测试，问题只是图像按钮无法重置。

image.setBackground(bitmapDrawable);

上面的这个方法似乎不适用于更新，我的快速解决方法是简单地保留代码原样并简单地添加检测onActivityResult以确定它是否真的是更新，然后将字节数据直接添加到数据库，而不是更新图像按钮然后recreate() Activity，过程昂贵，但对于简单的应用程序来说并不昂贵。

if (rowId != null) {
                ...
                recipe.setImage(DbBitmapUtility.getBytes(imageBitmap));
                recipeDAOImp.updateRecipe(recipe);
                recreate();
            }

一切正常。

Answer 2

我的猜测是问题出在您的 DAO 代码中。我有一个类似的设置（带有 text 和 blob 列的 sqlite 表，都得到更新），所以我知道你想要做的事情是可能的。