我有一个 Android 应用程序，可以下载和播放 mp3 文件。但我想在下载时加密音频文件，然后解密以播放它。我已经在互联网上到处检查但没有找到任何解决方案。谁能帮助我如何在下载时加密音频文件，然后在播放时解密 这是我下载文件的代码
private void download() {
if (Constant.arrayList_play.size() > 0) {
File root = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Myapp/cache");
if (!root.exists()) {
root.mkdirs();
}
File file = new File(root, Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name() + ".mp3");
if (!file.exists()) {
String url = Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Url();
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
request.setDescription(getResources().getString(R.string.downloading) + " - " + Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name());
request.setTitle(Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name());
request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationUri(Uri.parse("file://" + Environment.getExternalStorageDirectory().getAbsolutePath() + "/Myapp/cache/" + Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name() + ".mp3"));
DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
manager.enqueue(request);
new AsyncTask<String, String, String>() {
@Override
protected String doInBackground(String... strings) {
String json = JsonUtils.getJSONString(Constant.URL_DOWNLOAD_COUNT + Constant.arrayList_play.get(viewpager.getCurrentItem()).getId());
Log.e("aaa - ", json);
return null;
}
}.execute();
Toast.makeText(MainActivity.this, getResources().getString(R.string.downloading), Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, getResources().getString(R.string.already_download), Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(MainActivity.this, getResources().getString(R.string.no_song_selected), Toast.LENGTH_SHORT).show();
}
}
那么您能帮我提供一个代码吗？
我已经找到了我的问题的解决方案，并且已经在我的应用程序中使用它很多天了，没有任何问题，所以我认为回答我自己的问题也很好，因为许多用户在评论中要求解决方案。所以只需按照以下代码操作即可-
//Downloading and encrypting the audio
AesCipherDataSink encryptingDataSink = new AesCipherDataSink(
Util.getUtf8Bytes("4J95qN8RxBP8hTpk"),
new DataSink() {
private FileOutputStream fileOutputStream;
@Override
public void open(DataSpec dataSpec) throws IOException {
fileOutputStream = new FileOutputStream(file);
}
@Override
public void write(byte[] buffer, int offset, int length) throws IOException {
fileOutputStream.write(buffer, offset, length);
}
@Override
public void close() throws IOException {
fileOutputStream.close();
}
});
// Push the data through the sink, and close everything.
encryptingDataSink.open(new DataSpec(Uri.fromFile(file)));
URL downloadURL = new URL(strings[0]);
HttpURLConnection connection = (HttpURLConnection) downloadURL.openConnection();
connection.setChunkedStreamingMode(0);
connection.setDoInput(true);
connection.connect();
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
return "Server error";
}
InputStream inputStream = connection.getInputStream();
byte[] buffer = new byte[1024];
int newLength;
while ((newLength = inputStream.read(buffer)) > 0) {
encryptingDataSink.write(buffer, 0, newLength);
}
encryptingDataSink.close();
inputStream.close();
//decrypting and playing the audio
DataSource.Factory factory =
new CustomDataSourceFactory(
context,
new OkHttpDataSourceFactory(new OkHttpClient(), Util.getUserAgent(context,
context.getResources().getString(R.string.app_name)))
);
MediaSource videoSource =
new ProgressiveMediaSource.Factory(factory)
.createMediaSource(Uri.parse(tempFile.getAbsolutePath()));
exoPlayer.addMediaSource(videoSource);
//CustomDataSourceFactoryClass
public class CustomDataSourceFactory implements DataSource.Factory {
private final Context context;
private final DataSource.Factory baseDataSourceFactory;
public CustomDataSourceFactory(Context context, DataSource.Factory baseDataSourceFactory) {
this.context = context.getApplicationContext();
this.baseDataSourceFactory = baseDataSourceFactory;
}
@Override
public DataSource createDataSource() {
return new CryptedDefaultDataSource(context, baseDataSourceFactory.createDataSource());
}
}
//CryptedDafaultDataSource
public class CryptedDefaultDataSource implements DataSource {
private final List<TransferListener> transferListeners;
private final DataSource baseDataSource;
private @Nullable
DataSource fileDataSource,aesCipherDataSource,dataSource;
private Context context;
CryptedDefaultDataSource(Context context, DataSource baseDataSource) {
this.context=context;
this.baseDataSource = Assertions.checkNotNull(baseDataSource);
transferListeners = new ArrayList<>();
}
@Override
public void addTransferListener(TransferListener transferListener) {
baseDataSource.addTransferListener(transferListener);
transferListeners.add(transferListener);
maybeAddListenerToDataSource(fileDataSource, transferListener);
maybeAddListenerToDataSource(aesCipherDataSource, transferListener);
}
@Override
public long open(DataSpec dataSpec) throws IOException {
Assertions.checkState(dataSource == null);
if (Util.isLocalFileUri(dataSpec.uri)) {
dataSource = getCryptedDataSource(getFileDataSource());
} else {
dataSource = getCryptedDataSource(baseDataSource);
}
return dataSource.open(dataSpec);
}
@Override
public int read(byte[] buffer, int offset, int readLength) throws IOException {
return Assertions.checkNotNull(dataSource).read(buffer, offset, readLength);
}
@Nullable
@Override
public Uri getUri() {
return dataSource == null ? null : dataSource.getUri();
}
@Override
public Map<String, List<String>> getResponseHeaders() {
return dataSource == null
? DataSource.super.getResponseHeaders()
: dataSource.getResponseHeaders();
}
@Override
public void close() throws IOException {
if (dataSource != null) {
try {
dataSource.close();
} finally {
dataSource = null;
}
}
}
private DataSource getFileDataSource() {
if (fileDataSource == null) {
fileDataSource = new FileDataSource();
addListenersToDataSource(fileDataSource);
}
return fileDataSource;
}
private DataSource getCryptedDataSource(DataSource upstreamDataSource) {
if (aesCipherDataSource == null) {
aesCipherDataSource = new AesCipherDataSource("4J95qN8RxBP8hTpk".getBytes(),upstreamDataSource);
addListenersToDataSource(aesCipherDataSource);
}
return aesCipherDataSource;
}
private void addListenersToDataSource(DataSource dataSource) {
for (int i = 0; i < transferListeners.size(); i++) {
dataSource.addTransferListener(transferListeners.get(i));
}
}
private void maybeAddListenerToDataSource(
@Nullable DataSource dataSource, TransferListener listener) {
if (dataSource != null) {
dataSource.addTransferListener(listener);
}
}
}
亲爱的先生，我需要您的大力帮助。我已从 Android 应用程序和密钥加密音频文件...我需要一些解密帮助。 ;请发送您的电子邮件地址，我无法发送附件...请。