Save / Load image to/from local storage

问题

First of all, my permissions:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

My methods to save and get the image:

private void saveIamgeToLocalStore(Bitmap finalBitmap) { 
        String root = Environment.getExternalStorageDirectory().toString();
        File myDir = new File(root + "/temp");    
        myDir.mkdirs(); 
        String fname = "Profile_Image.png";
        File file = new File (myDir, fname);
        if (file.exists()) file.delete(); 
        try {
            FileOutputStream out = new FileOutputStream(file);
            finalBitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
            out.flush();
            out.close(); 
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void loadImageFromLocalStore(String imageURI) { 
        try {
            Uri uri = Uri.parse(Environment.getExternalStorageDirectory().toString() + imageURI); 
            Bitmap bitmap = BitmapFactory.decodeStream(getActivity().getContentResolver().openInputStream(uri));
            profileImage.setImageBitmap(bitmap);
            profileImage.setTag("Other");
            select_image_button.setText(R.string.button_remove_profile_picture); 
        } catch (FileNotFoundException e) { 
            e.printStackTrace();
        } 
    }

Usage:

saveIamgeToLocalStore(BitmapFactory.decodeFile(picturePath));
loadImageFromLocalStore("/temp/Profile_Image.png");

I'm getting a

java.io.FileNotFoundException: No content provider: ... 

warning.

What am I missing?

PS: The image gets saved in /mnt/sdcard/temp/ . The warning appears when loading the image.

回答1:

Is your file getting saved? In case yes, may be the mediascanner is not triggered before you do a read of the file. Since the mediascanner is not triggered, so content provider wont have the entry for your file (your file is not indexed).In case your file is getting saved with "saveIamgeToLocalStore", then trigger mediascanner from code once like this:

sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri
                        .parse("file://"
                                + Environment.getExternalStorageDirectory())));

and then do a read on the file. It should work.

回答2:

You need to write file existing check. Then it'll be easier to find problem. Short example

File test = new File (URI)
if ( test.exists() )
{
    // do your computation
} else 
{
    // find problem in file path
}

来源：https://stackoverflow.com/questions/18073260/save-load-image-to-from-local-storage