explorer v2

FileExplorer.java

import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

public class FileExplorer extends AppCompatActivity {

    private TextView tvPath;
    private ListView listView;

    private List<FileData> allFiles, dirFiles;

    private static String currentDirectory = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_file_explorer);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        initViews();

        currentDirectory = Environment.getExternalStorageDirectory().toString();
        dirFiles = new ArrayList<>();
        allFiles = getDirFiles();

        populateListView();

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

                String fName = allFiles.get(i).getfName();
                File file = new File(currentDirectory, fName);

                if (file.isFile()) {
                    Toast.makeText(getApplicationContext(), "this is a txt file", Toast.LENGTH_LONG).show();
                } else {
                    currentDirectory = file.toString();
                    populateListView();
                }
            }
        });
    }

    private List<FileData> getDirFiles() {
        dirFiles.clear();
        File dir = new File(currentDirectory);

        for (File file : dir.listFiles()) {
            if ((file.isFile() && file.getName().endsWith(".txt")) || file.isDirectory()) {
                dirFiles.add(new FileData(file.getName(), file.isDirectory()));
            }
        }
        tvPath.setText(dir.toString());
        return dirFiles;
    }

    private void populateListView() {
        allFiles = getDirFiles();
        listView.setAdapter(new FileAdapter(FileExplorer.this, allFiles));
    }

    public void clickEvent(View view) {

        switch (view.getId()) {

            case R.id.iv_new_folder:
                createNewFolderDialog();
                break;
        }
    }

    private void createNewFolderDialog() {
        final AlertDialog builder = new AlertDialog.Builder(FileExplorer.this).create();
        View v = LayoutInflater.from(this).inflate(R.layout.new_folder_dialog, null);
        final EditText folderName = v.findViewById(R.id.et_new_folder_name);
        builder.setView(v);

        builder.setTitle("New Folder");

        builder.setButton(DialogInterface.BUTTON_POSITIVE, "create", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                String name = folderName.getText().toString().trim();
                if (name.length() > 0) {
                    createFolder(name);
                }
            }
        });

        builder.setButton(DialogInterface.BUTTON_NEGATIVE, "cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                builder.dismiss();
            }
        });
        builder.show();
    }

    private void createFolder(String folderName) {

        boolean created = false;
        File dir = new File(currentDirectory, folderName);

        if (!dir.exists()) {
            created = dir.mkdirs();
        } else {
            msg("folder already exists!");
        }
        if (!created) {
            msg("unable to create new folder");
        } else {
            populateListView();
            msg("new folder created");
        }
    }

    private void initViews() {
        listView = findViewById(R.id.lv_files);
        tvPath = findViewById(R.id.tv_path);
    }

    private void msg(String s) {
        Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onBackPressed() {
        if (!currentDirectory.equals(Environment.getExternalStorageDirectory().toString())) {
            File c = new File(currentDirectory);
            currentDirectory = c.getParent();
            populateListView();
        } else {
            super.onBackPressed();
        }
    }
}