Android: decodeFile always returns null for file in internal storage

问题

I have a file saved locally into the application's private storage. I have verified it exists, however whenever I call BitmapFactory.decodeFile it always returns null.

If I save the file as a resource and use ImageView.setImageResource, it always shows up fine.

What is the problem?

Here is the snippet:

filename = "test.png";

if (doesFileExist(filename))
    Bitmap bMap = BitmapFactory.decodeFile(filename);

I've also tried:

Bitmap bMap = BitmapFactory.decodeFile(getFilesDir().getPath()
                    + filename);

回答1:

This question has been answered before such as here: BitmapFactory.decodeFile returns null even image exists

This was exactly what I needed:

String fname=new File(getFilesDir(), "test.png").getAbsolutePath();

回答2:

Folks, files stored in app resource should be referenced in special way. E.g. if file is located in assets and named as "myfile.png" it has to be referenced as:

String uriString="file:///android_asset/myfile.png";
Uri uri=Uri.parse(uriString);

回答3:

Instead of using BitmapFactory.decodeFile, try using InputStream:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) { 
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent); 

    if(resultCode == RESULT_OK){          
        Uri selectedImage = imageReturnedIntent.getData();
        InputStream imageStream = getContentResolver().openInputStream(selectedImage);
        Bitmap yourSelectedImage = BitmapFactory.decodeStream(imageStream);

回答4:

BitmapFactory.decodeFile expects a file path without the scheme. I.e. without the file:// in the beginning.

If you're handling a Uri, don't just .toString() it, but instead call .getPath() on it, and pass that to the method.

回答5:

Could you try fileList()? It

returns an array of strings naming the private files associated with this Context's application package.

回答6:

For me I was getting image from locally saved URL something like "file:///storage/emulated/0/...." (I have used Phonegap plugin to capture image. Plugin was giving me image path, which I need to use in native code)

Here is the code snippet which worked for me.

String captured_image_info = "file:///storage/emulated/0/Android/data/com.testapp/cache/1493809796526.jpg"
Uri uri=Uri.parse(captured_image_info);
largeLog("uri", "" + uri);

InputStream imageStream = getContentResolver().openInputStream(uri);

Bitmap bm = BitmapFactory.decodeStream(imageStream);

ByteArrayOutputStream baos = new ByteArrayOutputStream();

bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); //bm is the bitmap object

byte[] decodedBytes = baos.toByteArray();

Bitmap img_captured_image = BitmapFactory.decodeByteArray(decodedBytes, 0, decodedBytes.length);

来源：https://stackoverflow.com/questions/6013029/android-decodefile-always-returns-null-for-file-in-internal-storage

标签

android

bitmapfactory