我在我的安卓应用中有一个要求,需要以编程的方式下载并将文件保存到SD卡的特定文件夹中。 我已经开发了源代码,它是:
我在安卓应用中有一个需求:需要通过编程的方式将文件下载并保存到SD卡上指定的文件夹中。我已经编写了相应的源码,如下所示:
String DownloadUrl = "http://myexample.com/android/";
String fileName = "myclock_db.db";
DownloadDatabase(DownloadUrl,fileName);
// and the method is
public void DownloadDatabase(String DownloadUrl, String fileName) {
try {
File root = android.os.Environment.getExternalStorageDirectory();
File dir = new File(root.getAbsolutePath() + "/myclock/databases");
if(dir.exists() == false){
dir.mkdirs();
}
URL url = new URL("http://myexample.com/android/");
File file = new File(dir,fileName);
long startTime = System.currentTimeMillis();
Log.d("DownloadManager" , "download url:" +url);
Log.d("DownloadManager" , "download file name:" + fileName);
URLConnection uconn = url.openConnection();
uconn.setReadTimeout(TIMEOUT_CONNECTION);
uconn.setConnectTimeout(TIMEOUT_SOCKET);
InputStream is = uconn.getInputStream();
BufferedInputStream bufferinstream = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(5000);
int current = 0;
while((current = bufferinstream.read()) != -1){
baf.append((byte) current);
}
FileOutputStream fos = new FileOutputStream( file);
fos.write(baf.toByteArray());
fos.flush();
fos.close();
Log.d("DownloadManager" , "download ready in" + ((System.currentTimeMillis() - startTime)/1000) + "sec");
int dotindex = fileName.lastIndexOf('.');
if(dotindex>=0){
fileName = fileName.substring(0,dotindex);
}
catch(IOException e) {
Log.d("DownloadManager" , "Error:" + e);
}
}
现在的问题是只有一个名为myclock_db.db的空文件保存在路径中。但我需要下载并将文件内容保存到特定文件夹中。尝试了几种方法来获取文件下载,但都失败了。