在Android设备上显示所有图像

Question

I'm trying to create an application that on one of its activities it displays all the images on the device for the user to chose one of them.

I managed to only display all the images on the DCIM/Camera folder.

This is my code for displaying the images:

GridView gridview = (GridView) findViewById(R.id.gridview);
imageAdapter = new ImageAdapter(this);
gridview.setAdapter(imageAdapter);
gridview.setBackgroundColor(getResources().getColor(R.color.Black));

String ExternalStorageDirectoryPath = Environment.getExternalStorageDirectory().getAbsolutePath();

String targetPath = ExternalStorageDirectoryPath + "/DCIM/Camera";

Toast.makeText(getApplicationContext(), targetPath, Toast.LENGTH_LONG).show();
File targetDirector = new File(targetPath);

File[] files = targetDirector.listFiles();
for (File file : files)
    imageAdapter.add(file.getAbsolutePath());

Can someone help me here?

Thank you in advance!

Answer 1

On click (maybe upload button) :

 Intent intent = new Intent();
                intent.setType("image/*");
                intent.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE);

When user has selected an image :

 @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == PICK_IMAGE && resultCode == Activity.RESULT_OK && null != data) {
            Uri selectedImage = data.getData();

            BitmapFactory.Options options = new BitmapFactory.Options();
            //options.inSampleSize = 8;
            final InputStream ist;
            try {
                ist = mActivity.getContentResolver().openInputStream(selectedImage);
                Bitmap bitmap = BitmapFactory.decodeStream(ist, null, options);
                mPicturePath = compressImage(bitmap).getAbsolutePath();
                //recycling bitMap to overcome OutOfMemoryError
                if(bitmap!=null){
                    bitmap.recycle();
                    bitmap=null;
                }
                ist.close();

            //you have mPicturePath do something with it!
            } catch (FileNotFoundException e) {
                logoUploadFaied();
                e.printStackTrace();
            } catch (IOException e) {
                logoUploadFaied();
                e.printStackTrace();
            }
        } else {
           //Not uploading
        }
    }

Here is Compress Image code, it takes in a bitmap as argument, stores it locally (compressed) and returns file path. Excellent if you want to upload your images to server like whatsapp:

 public File compressImage(Bitmap bmp) {
        Bitmap scaledBitmap = null;

        int actualHeight = bmp.getHeight();
        int actualWidth = bmp.getWidth();

//      max Height and width values of the compressed image is taken as 816x612
        float imgRatio = actualWidth / actualHeight;
        float maxRatio = logoMaxWidth / logoMaxHeight;
//      width and height values are set maintaining the aspect ratio of the image
        if (actualHeight > logoMaxHeight || actualWidth > logoMaxWidth) {
            if (imgRatio < maxRatio) {
                imgRatio = logoMaxHeight / actualHeight;
                actualWidth = (int) (imgRatio * actualWidth);
                actualHeight = (int) logoMaxHeight;
            } else if (imgRatio > maxRatio) {
                imgRatio = logoMaxWidth / actualWidth;
                actualHeight = (int) (imgRatio * actualHeight);
                actualWidth = (int) logoMaxWidth;
            } else {
                actualHeight = (int) logoMaxHeight;
                actualWidth = (int) logoMaxWidth;
            }
        }
        try {
            scaledBitmap = Bitmap.createScaledBitmap(bmp, actualWidth, actualHeight, true);
        } catch (OutOfMemoryError exception) {
            logoUploadFaied();
            exception.printStackTrace();
        }
        String uriSting = (System.currentTimeMillis() + ".jpg");
        File file = new File(Environment.getExternalStorageDirectory()
                + File.separator + uriSting);
        try {
            file.createNewFile();
        } catch (IOException e) {
            logoUploadFaied();
            e.printStackTrace();
        }

        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(file);
        } catch (FileNotFoundException e) {
            logoUploadFaied();
            e.printStackTrace();
        }
        try {
            fos.write(getBytesFromBitmap(scaledBitmap));
            fos.close();
            //recycling bitMap to overcome OutOfMemoryError
            if(scaledBitmap!=null){
                scaledBitmap.recycle();
                scaledBitmap=null;
            }
        } catch (IOException e) {
            logoUploadFaied();
            e.printStackTrace();
        }
        return file;
    }