Trying to load and read images from SD card android

Question

What I am trying to do:

I am trying to load all the images that I have onto the phones SD card when the app is created. I then have a button and when I click the button, the next image should show.

What I've done:

So far I have included this code in the method, however I don't know how to add multiple images into the folder. 方法中，但是我不知道如何将多个图像添加到文件夹中。

 File sdCardDirectory = Environment.getExternalStorageDirectory();
    File image = new File(sdCardDirectory, "uct.png");
    boolean success = false;

    // Encode the file as a PNG image.
    FileOutputStream outStream;
    try {

        outStream = new FileOutputStream(image);
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, outStream);
    /* 100 to keep full quality of the image */
        outStream.flush();
        outStream.close();
        success = true;
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

At the moment I have an array of of image IDs, these images are stored in the Drawable folder at the moment.

int[] images = {R.drawable.img1,R.drawable.img2,R.drawable.img3,R.drawable.img4};

Then I have an method that increments a private index variable to set the Image Resource like so (here imgView is the ImageView). 方法，可以增加一个私有索引变量来像这样设置Image Resource（此处imgView是ImageView）。

imgView.setImageResource(images[current_image_index]);

What I don't know how to do:

Firstly, I don't know how to add multiple images to the SD card in the onCreate() method. Also I am not sure what the best way to go about loading the 'correct' image from the SD when the button is clicked.

I hope this makes sense, please remark if anything needs to be clarified.

Answer 1

If i were in your case,

1. Create the ViewPager to show all images.

2. And you can get all images url using this code.

     String[] STAR = {"*"}; ArrayList<String> imageUri = new ArrayList<>(); Cursor cursor = getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI , STAR, null, null, null); if (cursor != null) { if (cursor.moveToFirst()) { do { String path = cursor.getString(cursor .getColumnIndex(MediaStore.Images.Media.DATA)); Log.i("Path", path); imageUri.add(path); getDate(path); } while (cursor.moveToNext()); } } 

3. You can pass the imageUri ArrayList to Viewpager adapter.At viewPager adpter you can use any image library to load image. In case of Picasso .

   Picasso.with(context) .load(uri) .resize(150,150) .centerCrop() .into(imageView);