Question

我过去常常像firstName中的SharedPreferences一样：

private String filename = "mySharedString";
private SharedPreferences someData;
someData = getSharedPreferences(filename, 0);
Editor editor = someData.edit();
editor.putString("firstName", phoneNumber);
someData.getString("firstName", "NULL");

效果很好。现在我想保存可能为4 MB

的图像的base 64

SharedPreferences可以保存base 64吗？或者那个尺寸对它来说很大？

Answer 1

不要这样做。 SharedPreferences的文件大小为4MB。 SharedPreferences旨在将私有原始数据存储在键值对中，而且肯定不会存储在文件中。对于存储大文件，请使用内部/外部存储，并在数据库中保留Uri。

Answer 2

考虑到您的图片位于路径 - ＆gt; “/sdcard/test.jpg”，请参阅下面的代码

/*Get image into file*/
File image_file = new File("/sdcard/test.jpg");
/*Get absolute path in bitmap*/
Bitmap mBitmap = BitmapFactory.decodeFile(image_file.getAbsolutePath());
/*Instantiate Byte Array Output Stream to compress the bitmap*/
ByteArrayOutputStream bao_stream = new ByteArrayOutputStream();
/*Compress bitmap*/
mBitmap.compress(Bitmap.CompressFormat.PNG, 90, stream);
/*Get byteArray from stream*/
byte[] arr_byte_image = bao_stream.toByteArray();
/*Base6e class has a method name encodeToString using which you can get string from byteArray*/
String img_base64_str = Base64.encodeToString(arr_byte_image, 0);`

现在我们有包含base64字符串格式的整个图像的字符串，我们可以轻松地将其存储到SharedPreferences

如果上述代码有任何疑问，请与我们联系。

Answer 3

尝试此操作以保存在内存中

public void savedImage(byte[] data) {
    InputStream in = new ByteArrayInputStream(data);
    BitmapFactory.Options options = new BitmapFactory.Options();
    Bitmap preview_bitmap = BitmapFactory.decodeStream(in, null, options);
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    preview_bitmap.compress(Bitmap.CompressFormat.JPEG, 70, stream);
    byte[] byteArray = stream.toByteArray();
    final String newData = Base64.encodeToString(byteArray, 0);
    FileOutputStream outStream = null;
    try {
        outStream = new FileOutputStream(new File(
                Environment.getExternalStorageDirectory(), "ImageName.jpg"));
        outStream.write(byteArray);
        outStream.close();
    } catch (FileNotFoundException e) {
        Log.d("No File", e.getMessage());
    } catch (IOException e) {
        Log.d("IO Error", e.getMessage());
    }
}

Answer 4

虽然这是个坏主意，但你可以这样做

Bitmap photo=BitmapFactory.decodeResource(getResources(), R.drawable.addphoto);

    ByteArrayOutputStream bao = new ByteArrayOutputStream();
                 photo.compress(Bitmap.CompressFormat.JPEG, 100, bao);
                 byte [] ba = bao.toByteArray();
                 String ba1=Base64.encodeBytes(ba);

and store this string ba1 to your `SharedPreferences`

private String filename = "mySharedString";
private SharedPreferences someData;
someData = getSharedPreferences(filename, 0);
Editor editor = someData.edit();
editor.putString("firstName", phoneNumber);
editor.putString("ImageData", ba1);
editor.commit()

我认为通过这种方式，您可以将图像保存在共享偏好中。

如何在共享偏好中保存图像库64？

4 个答案: