I'm currently making a instagram type of app in Android Studio, my app only shows the newest pic at the bottom of the grid. The Collections.reverse(arrayList) is not working

here's my main.java

package com.example.mygram;


import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.example.mygram.utils.SpacingItemDecoder;



import java.util.ArrayList;
import java.util.Collections;

import de.hdodenhof.circleimageview.CircleImageView;

public class MainActivity extends AppCompatActivity {

    private static final int IMAGE_PICK_CODE=1000;
    private static final int PERMISSION_CODE=1001;

    RecyclerView recyclerView;
    TextView textView;
    Button pick, gallery;
    CircleImageView profpic;

    ArrayList <Uri> uri = new ArrayList<>();

    RecyclerAdapter adapter ;

    private static final int Read_Permission = 101;
    private static final int PICK_IMAGE = 1;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        profpic = findViewById(R.id.profile_image);
        gallery = findViewById(R.id.select);
        gallery.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(Intent.ACTION_PICK);
                intent.setType("image/*");
                galleryActivityResultLauncher.launch(intent);
            }
        });

        textView = findViewById(R.id.totalPhotos);
        recyclerView = findViewById(R.id.recyclerView_Gallery_Images);
        pick = findViewById(R.id.pick);

        adapter = new RecyclerAdapter(uri);
        recyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));
        SpacingItemDecoder itemDecorator = new SpacingItemDecoder(10);
        recyclerView.addItemDecoration(itemDecorator);
        recyclerView.setAdapter(adapter);
        Collections.reverse(uri);


        pick.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

                    ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, Read_Permission);

                    return;
                }

                Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
                intent.setType("image/*");
                if  (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2){
                    intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
                }
                //intent.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE);
            }
        });
    }

    private ActivityResultLauncher<Intent> galleryActivityResultLauncher = registerForActivityResult(
            new ActivityResultContracts.StartActivityForResult(),
            new ActivityResultCallback<ActivityResult>() {
                @Override
                public void onActivityResult(ActivityResult result) {
                    if (result.getResultCode() == Activity.RESULT_OK){
                        Intent data = result.getData();
                        Uri imageUri = data.getData();

                        profpic.setImageURI(imageUri);
                    }
                    else{
                        Toast.makeText(MainActivity.this, "Cancelled", Toast.LENGTH_SHORT).show();
                    }
                }
            }
    );



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

        if (requestCode == PICK_IMAGE && resultCode == RESULT_OK && null != data){
            if(data.getClipData()!=null){

                int countofImages = data.getClipData().getItemCount();
                for(int i=0; i<countofImages; i  ){
                    Uri imageuri = data.getClipData().getItemAt(i).getUri();
                    uri.add(imageuri);
                }
                adapter.notifyDataSetChanged();
                textView.setText("");
            }else{
                Uri imageuri = data.getData();
                uri.add(imageuri);
            }
            adapter.notifyDataSetChanged();
            textView.setText("");
        }else{
            Toast.makeText(this, "You haven't pick any images", Toast.LENGTH_SHORT).show();
        }

    }
}

here's my adapter.java

package com.example.mygram;

import android.media.Image;
import android.net.Uri;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

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

    private ArrayList<Uri> uriArrayList;

    public RecyclerAdapter(ArrayList<Uri> uriArrayList) {
        this.uriArrayList = uriArrayList;
    }

    @NonNull
    @Override
    public RecyclerAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View view = inflater.inflate(R.layout.custom_single_image,parent, false);

        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerAdapter.ViewHolder holder, int position) {
        holder.imageView.setImageURI(uriArrayList.get(position));

    }

    @Override
    public int getItemCount() {

        return uriArrayList.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        ImageView imageView;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            imageView = itemView.findViewById(R.id.image);
        }
    }
}

I want my app to display the last selected images at the top and first grid. I dont know what code should I use and where to put it. Please help, thank you!

CodePudding user response：

I think it can be work reverse you array before initialize your adapter. Like this:

 Collections.reverse(uri);
adapter = new RecyclerAdapter(uri);
   

CodePudding user response：

You Can Reverse this Layout Manager

Step1- goto your ArrayList

Step2- Reverse Collections.reverse(mArrayList);

Step3- Set Adapter