Question

我创建了一个Android应用程序来下载图像并将其保存到外部目录，但应用程序下载文件并将其保存到内部目录。这是我的代码

protected String doInBackground(String... aurl) {
        int count;

        try {

            File root = Environment.getExternalStorageDirectory();
            File dir = new File(root.getAbsolutePath() + "/storage/extSdCard/prateek");
            if(dir.exists() == false){
                dir.mkdirs();
            }

            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());

           // File SDCardRoot = Environment.getExternalStorageDirectory();
            //create a new file, to save the downloaded file
            File file = new File(dir,"downloaded_file.png");

            OutputStream output = new FileOutputStream(file);

            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;

    }

Answer 1

使用此 -

String exStoragePath = Environment.getExternalStorageDirectory().getAbsolutePath();
File dir = new File(exStoragePath + "/prateek/");

还在您的清单中加入<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />。

Answer 2

这是一些创建文件并在其中编写“Hello world”的代码。该文件将存储在/ myDir目录中。

你应该添加

＆LT; uses-permission android：name =“android.permission.WRITE_EXTERNAL_STORAGE”/＆gt;

到你的清单上工作。

    try {
        String root = Environment.getExternalStorageDirectory().toString();
        File myDir = new File(root + "/myDir");    
        myDir.mkdirs();
        File outFile = new File (myDir, "myFile");
        FileWriter fileWriter = new FileWriter(outFile);
        BufferedWriter out = new BufferedWriter(fileWriter);
        out.write("Hello world");
        out.close();
        Toast.makeText(this, "File successfully created to "+outFile.getAbsolutePath(), Toast.LENGTH_SHORT).show();
    } catch (IOException e) {
        Log.d("debug", "IOException: " + e.getMessage());
        Toast.makeText(this, "Error: file NOT created", Toast.LENGTH_SHORT).show();
    }

玩得开心。

Answer 3

File root = Environment.getExternalStorageDirectory();
            File dir = new File(root.getAbsolutePath() + "/storage/extSdCard/prateek");

如果我是对的，你的上述代码会给你路径为＆＃34; mnt / sdcard / storage / extSdCard / prateek＆＃34;所以不要使用root.getAbsolutePath（）直接给出路径＆＃34; / storage / extSdCard / prateek＆＃34;和它也不是存储在外部卡中的好习惯，因为在kitkat版本和其他一些手机中它不提供外部卡它会假设内存作为extsdcard

如何将下载的文件保存到外部存储

3 个答案: