我使用以下类下载文件并将其保存到SD卡。
class DownloadFileAsync extends AsyncTask<String, String, String> {
@SuppressWarnings("deprecation")
@Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_PROGRESS);
}
@Override
protected String doInBackground(String... aurl) {
int count;
try {
URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
int lenghtOfFile = conexion.getContentLength();
Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream(Environment.getExternalStorageDirectory().getAbsolutePath()+"PurchasedFrames/"+filename);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress(""+(int)((total*100)/lenghtOfFile));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
} catch (Exception e) {}
return null;
}
protected void onProgressUpdate(String... progress) {
Log.d("ANDRO_ASYNC",progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@Override
protected void onPostExecute(String unused) {
File file = new File("/sdcard/PurchasedFrames/", filename );
Bitmap myBitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
ImageView frame = (ImageView) findViewById(R.id.frame);
frame.setImageBitmap(myBitmap);
dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
}
}
对话框方法
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_DOWNLOAD_PROGRESS:
mProgressDialog = new ProgressDialog(this);
mProgressDialog.setMessage("Downloading file..");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(false);
mProgressDialog.show();
return mProgressDialog;
default:
return null;
}
}
我使用上述代码的问题,进度条会出现,但它会在没有完成的情况下消失,也不会发生下载。我无法注意到任何日志猫错误或调试中的任何其他错误。谁能说出会发生什么或如何克服这个问题?
所以我的
假设是正确的。在我的应用程序中,我使用了一个静态方法来返回一个文件路径,如果该路径不存在,则调用mkdirs()
。
对于您的代码,此方法如下所示:
public static File getSaveFilePath(String fileName) {
File dir = new File(Environment.getExternalStorageDirectory(), "PurchasedFrames");
dir.mkdirs();
File file = new File(dir, fileName);
return file;
}
然后将该行替换为输出流:
OutputStream output = new FileOutputStream(getSaveFilePath(fileName));
同时将异常块替换为catch (Exception e) { Log.e("DownloadFileAsync", e.toString()); "}