Krdytkyu

Gallery will be displayed in RecyclerView. User can select some images and delete it with one button.

It all works, but i think I have bad code, because I don't use some instruments (like fragment). I just don't understand what and where I need it exactly.

So I need help with readability (code style) and refactoring.

https://github.com/KirstenLy/GalleryApp

Some points about code:

MainActivity - Just logo and autoswitch to the next activity after two seconds.

GalleryActivity - Here i show the gallery and write code to take and save photo.

• 
  

  onCreate. I take a path to directory with images, and if it's ok, i create File files with images, then create ArrayList<String> imageNamesList which contains files names and put it into RecyclerView adapter to display.

  
  
  
  
  
  1. I use this library to animate my Recycler: https://github.com/wasabeef/recyclerview-animators. I used their methods and classes on 138 - 153 lines.
  
  
  
  


• 
  

  onActivityResult

  
  
  
  
  
  1. 
     tempFile.length() == 0 i used it, because if user activate camera and then press "back", photo will be created in tempFile but it will be empty, and RecyclerView will display empty cell with border.
  
  
  
  


• 
  

  Methods

  
  
  
  
  
  1. 
     deleteAllPhoto method. Method deleted all selected photo. I returned my own class DellAllPhotoResult and then work with it. Method count succsess and failed results.
  
  
  2. 
     takeAPhoto method. I use this to write it: https://developer.android.com/training/camera/photobasics
     
  
  
  
  

RVAdapter - my own adapter, extends RecyclerView.Adapter. He take ArrayList<String> imageNamesList, and create file and cell for every name on the list.

• 
  onBindViewHolder. Here i work with cell content. I used Glide library to avoid OOM when 5+ images displayed.
  
  
  
  
  1. 
     viewHolder.img.setOnClickListener. RecyclerView widget placed inside invisible layout named scaledImg. When user click on image, i make this layout visible and put user's image in it. This way i "scaled" image.
  
  
  
  

Functions - class with simple functions.

1. 
   prepareData. This method take file array and return Arraylist<String> with them names. Check on .jpg is about to avoid sutiation when user put file with another format in directory.

Another things are simple, in my opinion. But i can write explanation of any part, if someone need it.

MainActivity

public class MainActivity extends AppCompatActivity {



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);



        Runnable runnable = new Runnable() {

            @Override

            public void run() {

                Intent intent = new Intent(MainActivity.this, GalleryActivity.class);

                startActivity(intent);

                finish();

            }

        };

        Handler handler = new Handler();

        handler.postDelayed(runnable, 2000);

    }

}

GalleryActivity

public class GalleryActivity extends AppCompatActivity {

    final int REQUEST_TAKE_PHOTO = 1;

    private File tempFile;



    private void takeAPhoto(String PATH, int REQUEST_TAKE_PHOTO) {

        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {

            try {

                tempFile = Functions.createImageFile(PATH);

            } catch (IOException ex) {

                Toast.makeText(getApplicationContext(), "Denied. Create file error.", Toast.LENGTH_LONG).show();

                return;

            }

            if (tempFile != null) {

                Uri photoURI = FileProvider.getUriForFile(getApplicationContext(),

                        "com.kirsten.testapps.fileprovider",

                        tempFile);

                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);

                startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);

            }

        } else {

            Toast.makeText(getApplicationContext(), "Denied. Can't find a camera.", Toast.LENGTH_LONG).show();

        }

    }



    private DellAllPhotoResult deleteAllPhoto(RVAdapter adapter, ArrayList<String> imageNames, String PATH) {

        boolean isSelected = adapter.getIsSelected();

        boolean noErrorResult = true;

        int successDeletedFileCounter = 0;

        int failedDeletedFileCounter = 0;

        StringBuilder pathString = new StringBuilder();



        for (int i = 0; i < imageNames.size(); i++) {

            if (isSelected[i]) {

                tempFile = new File(pathString.

                        append(PATH).

                        append("/").

                        append(imageNames.get(i)).

                        toString());

                if (tempFile.delete() && !tempFile.exists()) {

                    successDeletedFileCounter++;

                } else {

                    failedDeletedFileCounter++;

                }

            }

        }

        if (failedDeletedFileCounter > 0) {

            noErrorResult = false;

        }

        return new DellAllPhotoResult(noErrorResult, successDeletedFileCounter, failedDeletedFileCounter);

    }



    @Override

    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

        if (requestCode == REQUEST_TAKE_PHOTO && tempFile != null) {

            if (tempFile.length() == 0) {

                if (!tempFile.delete()) {

                    Toast.makeText(this, "Unknown error, app will be closed", Toast.LENGTH_LONG).show();

                    android.os.Process.killProcess(android.os.Process.myPid());

                }

            }

        }

        recreate();

    }



    @Override

    public void onBackPressed() {

        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        builder.setMessage("Are you sure you want to exit?")

                .setCancelable(false)

                .setPositiveButton(R.string.yes_dialog, new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int id) {

                        android.os.Process.killProcess(android.os.Process.myPid());

                    }

                })

                .setNegativeButton(R.string.no_dialog, new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int id) {

                        dialog.cancel();

                    }

                });

        AlertDialog alert = builder.create();

        alert.show();

    }



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_gallery);



        final String PATH;

        try {

            PATH = getExternalFilesDir(DIRECTORY_PICTURES).getPath();

        } catch (NullPointerException ex) {

            Toast.makeText(getApplicationContext(), "Unknown error. Can't get access to app directory.", Toast.LENGTH_LONG).show();

            return;

        }



        File directory = new File(PATH);

        File files = directory.listFiles();



        if (files == null){

            Toast.makeText(getApplicationContext(), "Unknown error. App directory is not exist.", Toast.LENGTH_LONG).show();

            return;

        }



        final RecyclerView recyclerView = findViewById(R.id.image_gallery);

        recyclerView.setItemAnimator(new SlideInLeftAnimator());

        RecyclerView.LayoutManager layoutManager = new GridLayoutManager(this, 2);

        recyclerView.setLayoutManager(layoutManager);

        recyclerView.getItemAnimator().setMoveDuration(1000);

        recyclerView.getItemAnimator().setRemoveDuration(1000);

        recyclerView.getItemAnimator().setAddDuration(1000);



        final ArrayList<String> imageNamesList = Functions.prepareData(files);

        final ImageView scaledImage = findViewById(R.id.scaled_image);

        final RVAdapter adapter = new RVAdapter(getApplicationContext(), imageNamesList, PATH, scaledImage);



        ScaleInAnimationAdapter alphaAdapter = new ScaleInAnimationAdapter(adapter);

        alphaAdapter.setFirstOnly(false);

        alphaAdapter.setDuration(500);

        recyclerView.setAdapter(alphaAdapter);



        final Button takePhotoButton = findViewById(R.id.take_photo_button);

        takePhotoButton.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                takeAPhoto(PATH, REQUEST_TAKE_PHOTO);

            }

        });



        final Button delAllPhotoButton = findViewById(R.id.delete_all_photo_button);

        delAllPhotoButton.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                boolean isSelected = adapter.getIsSelected();

                boolean isSomethingSelected = Functions.checkArray(isSelected);



                if (!isSomethingSelected) {

                    Toast.makeText(getApplicationContext(), "No one image selected", Toast.LENGTH_LONG).show();

                    return;

                }



                DellAllPhotoResult result = deleteAllPhoto(adapter, imageNamesList, PATH);



                if (result.isResult()) {

                    Toast.makeText(getApplicationContext(), new StringBuilder().

                            append("Done.").

                            append(result.getSuccessResults()).

                            append(" files deleted.").

                            toString(), Toast.LENGTH_LONG).show();

                    recreate();

                } else {

                    Toast.makeText(getApplicationContext(), new StringBuilder().

                            append("Done. ").

                            append("Unknown error.").

                            append(result.getSuccessResults()).

                            append(" files deleted.").

                            append(result.getFailedResults()).

                            append(" files are not.").toString(), Toast.LENGTH_LONG).show();

                    recreate();

                }

            }

        });

    }

}

RVAdapter

public class RVAdapter extends RecyclerView.Adapter<RVAdapter.ViewHolder> {

    private ArrayList<String> imageNameList;

    private Context context;

    private final String PATH;

    private ImageView scaledImg;

    private static boolean isSelected;

    private boolean isScaled = false;





    public RVAdapter(Context context, ArrayList<String> imageNameList, String path, ImageView scaledImg) {

        this.imageNameList = imageNameList;

        this.context = context;

        this.PATH = path;

        this.scaledImg = scaledImg;

        isSelected = new boolean[imageNameList.size()];

    }



    private void deleteImageFromListWithRefresh(final RVAdapter.ViewHolder viewHolder, int i) {

        imageNameList.remove(i);

        notifyItemRemoved(i);

        notifyItemRangeChanged(i, imageNameList.size());

        viewHolder.cellLayout.removeAllViews();

        viewHolder.cellLayout.refreshDrawableState();

    }



    public boolean getIsSelected() {

        return isSelected;

    }



    @Override

    public RVAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {

        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.cell_layout, viewGroup, false);

        return new ViewHolder(view);

    }



    @Override

    public void onBindViewHolder(final RVAdapter.ViewHolder viewHolder, final int i) {

        final File image = new File(new StringBuilder().

                append(PATH).

                append("/").

                append(imageNameList.get(i)).

                toString());

        Glide.with(context).load(image).into(viewHolder.img);



        viewHolder.filename.setText(imageNameList.get(i));

        viewHolder.itemView.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                if (!isSelected[i]) {

                    isSelected[i] = !isSelected[i];

                    viewHolder.cellLayout.setBackgroundColor(context.getResources().getColor(R.color.colorCellActive));

                    viewHolder.filename.setTextColor(Color.BLACK);

                } else {

                    isSelected[i] = !isSelected[i];

                    viewHolder.cellLayout.setBackgroundColor(Color.TRANSPARENT);

                    viewHolder.filename.setTextColor(Color.WHITE);

                }

            }

        });



        viewHolder.img.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                if (!isScaled) {

                    scaledImg.setImageURI(Uri.fromFile(image));

                    scaledImg.setVisibility(View.VISIBLE);

                    isScaled = !isScaled;

                }

            }

        });





        scaledImg.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                scaledImg.setVisibility(View.INVISIBLE);

                isScaled = !isScaled;

            }

        });



        viewHolder.delButton.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                boolean isDeleted = image.delete();

                if (isDeleted) {

                    Toast.makeText(context, "Done.", Toast.LENGTH_LONG).show();

                    deleteImageFromListWithRefresh(viewHolder, i);

                } else if (image.exists()) {

                    Toast.makeText(context, "Unknown error. File was not deleted.", Toast.LENGTH_LONG).show();

                } else {

                    Toast.makeText(context, "Unknown error. Gallery refresh started...", Toast.LENGTH_LONG).show();

                    deleteImageFromListWithRefresh(viewHolder, i);

                }

            }

        });

    }



    @Override

    public int getItemCount() {

        return imageNameList.size();

    }



    class ViewHolder extends RecyclerView.ViewHolder {

        private TextView filename;

        private ImageView img;

        private Button delButton;

        private LinearLayout cellLayout;



        ViewHolder(View view) {

            super(view);

            filename = view.findViewById(R.id.filename);

            img = view.findViewById(R.id.img);

            delButton = view.findViewById(R.id.delete_button);

            cellLayout = view.findViewById(R.id.cell);

        }

    }

}

Functions

public class Functions {



    public static boolean checkArray(boolean checked) {

        for (boolean b : checked) {

            if (b) {

                return true;

            }

        }

        return false;

    }



    public static ArrayList<String> prepareData(File files) {

        if (files == null) {

            return null;

        }

        ArrayList<String> imageList = new ArrayList<>();

        for (File file : files) {

            if (!file.getName().endsWith(".jpg")) {

                continue;

            }

            imageList.add(file.getName());

        }

        return imageList;

    }



    public static File createImageFile(String path) throws IOException {

        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(new Date());

        String imageFileName = "JPEG_" + timeStamp + "_";

        return File.createTempFile(imageFileName, ".jpg", new File(path));

    }

}

DelAllPhotoResult

public class DellAllPhotoResult {



    private final boolean result;

    private final int successResults;

    private final int failedResults;



    public DellAllPhotoResult(boolean result, int sucsessResults, int failedResults) {

        this.result = result;

        this.successResults = sucsessResults;

        this.failedResults = failedResults;

    }



    public boolean isResult() {

        return result;

    }



    public int getSuccessResults() {

        return successResults;

    }



    public int getFailedResults() {

        return failedResults;

    }

}