android studio实现音乐下载

要实现音乐下载，你需要以下几个步骤：

1. 在AndroidManifest.xml中添加网络访问权限：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2. 创建一个异步任务类，下载音乐文件：

public class DownloadMusicTask extends AsyncTask<String, Integer, String> {

    private Context mContext;
    private ProgressDialog mProgressDialog;

    public DownloadMusicTask(Context context) {
        mContext = context;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        mProgressDialog = new ProgressDialog(mContext);
        mProgressDialog.setMessage("正在下载，请稍候...");
        mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        mProgressDialog.setMax(100);
        mProgressDialog.setCancelable(false);
        mProgressDialog.show();
    }

    @Override
    protected String doInBackground(String... params) {
        String url = params[0];
        String fileName = params[1];
        File file = new File(Environment.getExternalStorageDirectory() + "/" + fileName);
        try {
            URL musicUrl = new URL(url);
            URLConnection connection = musicUrl.openConnection();
            connection.connect();
            int fileLength = connection.getContentLength();
            InputStream input = new BufferedInputStream(musicUrl.openStream());
            OutputStream output = new FileOutputStream(file);
            byte[] data = new byte[1024];
            long total = 0;
            int count;
            while ((count = input.read(data)) != -1) {
                total += count;
                publishProgress((int) (total * 100 / fileLength));
                output.write(data, 0, count);
            }
            output.flush();
            output.close();
            input.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return file.getAbsolutePath();
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
        mProgressDialog.setProgress(values[0]);
    }

    @Override
    protected void onPostExecute(String filePath) {
        super.onPostExecute(filePath);
        mProgressDialog.dismiss();
        Toast.makeText(mContext, "下载完成，文件保存在" + filePath, Toast.LENGTH_LONG).show();
    }
}

3. 在Activity中调用异步任务类：

String url = "http://example.com/music.mp3";
String fileName = "music.mp3";
DownloadMusicTask task = new DownloadMusicTask(this);
task.execute(url, fileName);

这样就可以实现音乐文件的下载了。请注意，这里的文件保存路径默认为SD卡根目录。如果你需要保存到其他位置，请修改代码中的路径。