Android Download Manager save to /system

问题

I'm just playing around with Android Studio and I'm trying to figure out how to Download a file into /system.

I understand I need root for this and I already got that part working, the only trouble I'm having is with

request.setDestinationInExternalPublicDir("/system/", "test.jpg");

The goal is to download a file and save it to /system with the file name being test.jpg.

So the end is the file is located at /system/test.jpg.

The issue with this is that DownloadManager is saving it to internal storage and is creating a new folder named 'system'.

I can tell it has something to do with setDestinationInExternalPublicDir but I'm just not sure what to change it to.

Thanks again

回答1:

What I did is that:
(It's a part in one of my projects)

/*****DOWNLOAD FILE*****/
DownloadManager.Request request = new DownloadManager.Request(Uri.parse("https://github.com/pelya/android-keyboard-gadget/blob/master/hid-gadget-test/hid-gadget-test?raw=true"));
request.setDescription("hid-gadget-test");
request.setTitle("hid-gadget-test");
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
    request.allowScanningByMediaScanner();
    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE);
}
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "hid-gadget-test"); /*****SAVE TO DOWNLOAD FOLDER*****/


DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
manager.enqueue(request);

File mvfile = new File("/sdcard/"+Environment.DIRECTORY_DOWNLOADS+"/hid-gadget-test");
while (!mvfile.exists()) {}  /*****WAIT UNTIL DOWNLOAD COMPLETE*****/
try {
    Thread.sleep(5000);
} catch (InterruptedException ignored) {}


try {  /*****RUN MV-COMMAND TO MOVE TO ROOT DIR*****/
    Process su = Runtime.getRuntime().exec("su");
    DataOutputStream outputStream = new DataOutputStream(su.getOutputStream());

    outputStream.writeBytes("mv /sdcard/"+Environment.DIRECTORY_DOWNLOADS+"/hid-gadget-test /data/local/tmp/hid-gadget-test\n");
    outputStream.flush();

    outputStream.writeBytes("exit\n");
    outputStream.flush();
    su.waitFor();
} catch (IOException e) {
    Toast.makeText(getApplicationContext(), "IOException", Toast.LENGTH_SHORT).show();
} catch (InterruptedException e) {
    Toast.makeText(getApplicationContext(), "InterruptedException", Toast.LENGTH_SHORT).show();
}

The wait-until-download-complete-thingy is a bit hacky, I found it here. It will maybe not work with files that take more than 5 seconds to download

来源：https://stackoverflow.com/questions/35197618/android-download-manager-save-to-system

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java

android

android-download-manager