Android SharedPreferences保存位图 [英] Android SharedPreferences Save bitmap
问题描述
我的应用程序上有一个活动，该活动必须保存一些数据，并且该数据必须从其他活动中获取，所以我正在使用SharedPreferences来执行此操作，问题是，当我尝试保存位图时ImageView的内容:
I have an Activity on my app that has to save some data, and that data has to be accesed from other Activity, so i´m using SharedPreferences to do this, the problem is that, when i try to save the bitmap of an ImageView with:
ImageButton imgView = (ImageButton) findViewById(R.id.UserImageButton);
Bitmap bitmap = ((BitmapDrawable)imgView.getDrawable()).getBitmap();
editor.putInt("bitmap", bitmap);
或直接与:
ImageButton imgView = (ImageButton) findViewById(R.id.UserImageButton);;
editor.putInt("bitmap", ((BitmapDrawable)imgView.getDrawable()).getBitmap());
但是它不起作用. 我该如何保存?非常感谢
But it doesn´t work. How can I save it?? Thanks a lot
推荐答案
您只能在SharedPreference中添加布尔值，浮点数，整数，长整数，字符串值.但是您可以做的一件事是将Bitmap转换为Base64 String.然后从SharedPrefrence检索到它，然后将其转换为Bitmap.
You can add only Boolean, Float, Int, Long, String values in SharedPreference. But one thing you can do is converting Bitmap to Base64 String. And after retrieving it from SharedPrefrence convert it to Bitmap.
使用以下方法将位图转换为字节数组:
Use following method to convert bitmap to byte array:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos); //bm is the bitmap object
byte[] b = baos.toByteArray();
使用以下方法从字节数组中对base64进行编码
to encode base64 from byte array use following method
String encoded = Base64.encodeToString(b, Base64.DEFAULT);
And Save it to SharedPrefrence.
现在，假设您的图像数据在一个名为"encoded"的字符串中，那么下面的代码应该可以为您提供来自Base64字符串的BitMap:
Now assuming that your image data is in a String called encoded , the following should do give you BitMap from Base64 string:
byte[] imageAsBytes = Base64.decode(encoded.getBytes());
ImageView image = (ImageView)this.findViewById(R.id.ImageView);
image.setImageBitmap(BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length));
:)
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