将文件从 URL 替换为原始文件夹

Question

伙计们，我的 URL 中有一个文本文件。单击按钮后，我可以将其下载到 sdcard。

但我需要用原始文件夹中的文件替换下载的文件。两者是不同的文件。

这就是我从 URL 下载的方式

File sdcard = Environment.getExternalStorageDirectory();
File dir = new File (sdcard.getAbsolutePath() + "/varun");
dir.mkdirs();
try {
    u = new URL("http://hihowru.com/123.xml");
            file = new File(dir,"123.xml");
            startTime = System.currentTimeMillis();
                   Log.d("DownloadManager", "download begining");
                   Log.d("DownloadManager", "download url:" + url);
                   Log.d("DownloadManager", "downloaded file name:" + "a.mp3");
        URLConnection uconnection = u.openConnection();
        InputStream is = uconnection.getInputStream();
        BufferedInputStream bis = new BufferedInputStream(is);
                    baf = new ByteArrayBuffer(5000);
                       int current = 0;
                       while ((current = bis.read()) != -1) {
                          baf.append((byte) current);
                       }

                FileOutputStream fos;

                fos = new FileOutputStream(file);
                fos.write(baf.toByteArray());
                fos.flush();
                fos.close();

                Toast toast = Toast.makeText(getApplicationContext(), "Downloaded to Sdcard/varun"+audioxml, 0);
                toast.show();
                Log.d("DownloadManager", "download ready in" + ((System.currentTimeMillis() - startTime) / 1000) + " sec");
                Intent ii = new Intent(DownloadFiles.this,Relaxation.class);
                startActivity(ii);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

但我需要用原始文件夹中的文件替换这个文件（下载的文件）

下载文件名：hi.txt 原始文件夹名称：hw.txt

如何实现，请帮忙

Answer 1

您不能在android resources 或asset 目录中修改或写入文件。因为android apk文件是read only。所以你只能阅读它。最好的方法是将该文件复制到internal storage 中，然后从该路径使用，同样在从 url 下载文件更新到内部存储路径之后。

更新：

将文件从 /asset 复制到应用程序内部存储的代码。

private void copyFile(String filename) {
    AssetManager assetManager = this.getAssets();

    InputStream in = null;
    OutputStream out = null;
    try {
        in = assetManager.open(filename);
        String newFileName = "/data/data/" + this.getPackageName() + "/" + filename;
        out = new FileOutputStream(newFileName);

        byte[] buffer = new byte[1024];
        int read;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
        in.close();
        in = null;
        out.flush();
        out.close();
        out = null;
    } catch (Exception e) {
        Log.e("tag", e.getMessage());
    }

}