CODEWITHSUNDEEP
javaandroidandroid-bitmap
Nevi
Nevi

Reputation: 171

BitmapFactory.decodeFile return null

I'm having a problem for a few days now and I can't find the solution. I've been looking on the internet for hours but I can't find any answer that works for me. I'm making an app where I have to send pictures to a webservice. I'm using Fishbun to access to the phone gallery and pick some pictures. When the pictures are picked, I use Bitmapfactory.decodeFile() with the returned path from Fishbun to display the pictures on the screen. It works good. The path at this moment is:

/storage/emulated/0/DCIM/Camera/IMG_20160321_044346.jpg

Then, I save the path in a ArrayList which will be send to the webservice. When I use BitmapFactory.decodeFile() on the path from the ArrayList, it returns null. The path is exactly the same as the first time, but it seems like I can't decode it twice.
If I restart the app and take back the same picture as the first time in fishbun, the decodeFile() also returns null. Here is the code ....
Fishbun activity result:

protected void onActivityResult(int requestCode, int resultCode,
                                Intent imageData) {
    super.onActivityResult(requestCode, resultCode, imageData);

    switch (requestCode) {
        case Define.ALBUM_REQUEST_CODE:
            if (resultCode == RESULT_OK) {
                path = imageData.getStringArrayListExtra(Define.INTENT_PATH);
                int i = 0;
                int error=0;
                while(i<path.size()){
                    Bitmap bmp = BitmapFactory.decodeFile(path.get(i));
                    if(bmp.getWidth()<bmp.getHeight()) // bmp is not null the first time, null the second time
                    {
                        error++;
                        path.remove(i);
                        i--;
                    }
                    i++;
                }
                if(error>=1){
                    Toast.makeText(newStep7.this,R.string.rerrors, Toast.LENGTH_LONG).show();
                }
                if(path.size()>0) {
                    mainAdapter.changePath(path); //display the picture on the screen without changing the path, the method name is kinda wrong
                }
                break;
            }
    }
}

This is the decodeFile() before sending my request:

    String imgPath = rep.getImgList().get(0);
    File file = new File(imgPath);
    OutputStream os = new BufferedOutputStream(new FileOutputStream(file));
    Log.d("startedfromthebottom", file.getAbsolutePath()); //show the same path as in the activityresult above
    Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath()); //bitmap is always null
    bitmap.compress(Bitmap.CompressFormat.JPEG,100,os);

Could you help me find why my bitmap is null when I decode the same file twice ?

EDIT: I found the image file in my Android Device Monitor. The image size is 0 and can't be used anymore after the Outputstream

UPDATE: Little code change after applying bwt answer:

    String imgPath = rep.getImgList().get(0);
    File file = new File(imgPath);
    AtomicFile atomicFile =
            new AtomicFile(file);
    FileOutputStream fos = null;
    ObjectOutputStream oos = null;
    try {
        fos = atomicFile.startWrite();
        Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
        Log.d("showmethebitmap", bitmap.toString()); //Error: bitmap is null !
        oos = new ObjectOutputStream(fos);
        bitmap.compress(Bitmap.CompressFormat.JPEG,0,oos);
        oos.writeObject(bitmap);
        oos.flush();
        atomicFile.finishWrite(fos);
        ...
    } catch (IOException e) {
        atomicFile.failWrite(fos);
        throw e;
    } finally {
        if (oos != null) oos.close();
    }

Upvotes: 2

Views: 8819

Answers (2)

Ahmed na
Ahmed na

Reputation: 1154

I know the question has been answered ,however if someone still getting null make sure that the application has permission to read user's files

Upvotes: 2

Philippe Banwarth
Philippe Banwarth

Reputation: 17725

You should load the image first, then open the output stream, as this erases the existing content. 

  Log.d("startedfromthebottom", file.getAbsolutePath()); //show the same path as in the activityresult above
  Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath()); //bitmap is always null
  OutputStream os = new BufferedOutputStream(new FileOutputStream(file));
  bitmap.compress(Bitmap.CompressFormat.JPEG,100,os);

This is a bit dangerous because if something goes wrong the image is lost. It could be a good idea to use an AtomicFile.

Edit (based on your updated code) :

    String imgPath = rep.getImgList().get(0);
    File file = new File(imgPath);
    AtomicFile atomicFile =  new AtomicFile(file);
    FileOutputStream fos = null;
    try {
        // read the current image
        Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
        // open the stream (backup the current content)
        // from now on (and until finishWrite/failWrite) we cannot read the file directly
        fos = atomicFile.startWrite();
        Log.d("showmethebitmap", bitmap.toString()); //Error: bitmap is null !
        OutputStream oos = new BufferedOutputStream(fos);
        bitmap.compress(Bitmap.CompressFormat.JPEG,0,oos);
        // flush but do not close the stream (@see AtomicFile doc)
        oos.flush();
        // close the stream, remove the backup
        atomicFile.finishWrite(fos);
        ...
    } catch (IOException e) {
        // recover the content from the backup
        atomicFile.failWrite(fos);
        throw e;
    }

Upvotes: 0

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