我正在尝试下载pdf文件它工作得很好。但是在完成下载之前如果应用程序处于销毁状态，部分下载文件将自动删除。所以我可以再次开始下载。我已经使用过这个代码，但它无法正常工作
if (!file.exists()) {
try {
URL url = new URL(url_text.replace(" ", "%20"));
Log.e("tarikul", url + "");
HttpURLConnection c = (HttpURLConnection)
url.openConnection();
c.setConnectTimeout(5000);
c.setRequestMethod("GET");
c.connect();
int lengthOfFile = c.getContentLength();
if (lengthOfFile == 0)
Log.e("tarikul", "File length: " + lengthOfFile);
if (c.getResponseCode() == HttpURLConnection.HTTP_OK) {
Constants.FILE_DOWNLOADING = true;
Log.e("tarikul", "HTTP OK");
int count;
InputStream inputFile = new
BufferedInputStream(url.openStream(), 10 * 1024);
OutputStream outFile = new FileOutputStream(file);
Log.e("tarikul", "22");
byte data[] = new byte[1024];
long total = 0;
while ((count = inputFile.read(data)) != -1) {
total += count;
publishProgress("" + (int) ((total * 100) /
lengthOfFile));
outFile.write(data, 0, count);
}
Log.i("TEST", "Length Of File: " +lengthOfFile +
"\nTotal Downloaded: " +total);
if (lengthOfFile == total) {
Log.i("TEST", "Download Succeeded.");
}
outFile.flush();
outFile.close();
inputFile.close();
} else {
Log.i("TEST", "Response error.");
}
c.disconnect();
} catch (Exception e) {
Log.e("hello", "" + e.getMessage());
if (file.exists()) {
file.delete();
}
Constants.FILE_DOWNLOADING = false;
`