如何从Firebase仓库下载音频？

Question

我正在开发一个Android应用程序，用于从Firebase上传和下载音频，并且我已成功将三个音频文件（A.mp3，B.mp3和C.mp3）上传到Firebase存储。现在我要选择哪个文件要下载说B.mp3，这就是我遇到的问题。如何选择要下载然后下载的音频？

我有3个按钮，一个用于选择要上传的文件，一个上传按钮和一个下载按钮。

这是我的代码...

package com.hussainapplications.firebasestorageexample;

import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.OnProgressListener;
import com.google.firebase.storage.StorageReference;
import com.google.firebase.storage.UploadTask;

import java.io.File;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    Button buttonChoose,buttonUpload,buttonDownload;
    TextView fileselected;
    private StorageReference storageReference;
    private static final int PICK_IMAGE_REQUEST = 234;
    private Uri filePath;
    public static int fileCount=0;




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        buttonChoose=findViewById(R.id.buttonChoose);
        buttonUpload=findViewById(R.id.buttonUpload);
        buttonDownload=findViewById(R.id.buttonDownload);
        fileselected=findViewById(R.id.fileselected);
        storageReference = FirebaseStorage.getInstance().getReference();
        final ProgressDialog progressDialog = new ProgressDialog(this);



        buttonChoose.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


        Intent intent = new Intent();
        intent.setType("Audio/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent, "Select Audio"), PICK_IMAGE_REQUEST);


            }
        });




        buttonUpload.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

               fileCount++;



                if (filePath != null) {
            //displaying a progress dialog while upload is going on
            progressDialog.setTitle("Uploading");
            progressDialog.show();

            StorageReference riversRef = storageReference.child("Audio/audio" + fileCount);
            riversRef.putFile(filePath)
                    .addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                        @Override
                        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                            //if the upload is successfull
                            //hiding the progress dialog
                            progressDialog.dismiss();

                            //and displaying a success toast
                            Toast.makeText(getApplicationContext(), "File Uploaded ", Toast.LENGTH_LONG).show();
                        }
                    })
                    .addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception exception) {
                            //if the upload is not successfull
                            //hiding the progress dialog
                            progressDialog.dismiss();

                            //and displaying error message
                            Toast.makeText(getApplicationContext(), exception.getMessage(), Toast.LENGTH_LONG).show();
                        }
                    })
                    .addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
                        @Override
                        public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
                            //calculating progress percentage
                            double progress = (100.0 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();

                            //displaying percentage in progress dialog
                            progressDialog.setMessage("Uploading....");
                            //progressDialog.setMessage("Uploaded " + ((int) progress) + "%...");
                        }
                    });
        }
        //if there is not any file
        else {
            //you can display an error toast
        }









            }
        });


        buttonDownload.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                fileCount++;

                try {
              StorageReference riversRef = storageReference.child("Audio").child("New_Audio.mp3");
              //download
              riversRef = storageReference.child("Audio").child("New_Audio.mp3"+fileCount);
              File localFile  = new File(Environment.getExternalStoragePublicDirectory(
              Environment.DIRECTORY_DOWNLOADS), "New_Audio.mp3");
              localFile .createNewFile();
              riversRef.getFile(localFile);
              } catch (IOException e) {
              e.printStackTrace();
              }

            }
        });
    }






    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
            filePath = data.getData();
            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
                fileselected.setText("File Selected");

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }








}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:layout_width="200dp"
        android:layout_height="50dp"
        android:id="@+id/buttonChoose"
        android:text="Choose File"/>


    <Button
        android:layout_width="200dp"
        android:layout_height="50dp"
        android:id="@+id/buttonUpload"
        android:layout_below="@+id/buttonChoose"
        android:text="Upload"/>


    <Button
        android:layout_width="200dp"
        android:layout_height="50dp"
        android:id="@+id/buttonDownload"
        android:layout_below="@+id/buttonUpload"
        android:text="Download"/>

    <TextView
        android:id="@+id/fileselected"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/buttonChoose"
        android:layout_marginStart="7dp"
        android:textColor="#000"
        android:textStyle="bold"
        android:layout_toEndOf="@id/buttonChoose"
        android:textSize="20sp" />

</RelativeLayout>