下载pdf文件并将其保存到sdcard，然后从那里读取[重复]

Question

可能重复：
Download PDF from url and read it

我必须从一个 url 下载一个 pdf 文件并将其保存到 sd 卡中，然后才能阅读它。 我通过了很多代码，我发现了这个

Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("*url for your pdf*"));
startActivity(browserIntent);

但是如何将它保存在我想要的路径中的 sd 卡中，然后从那里读取它。

Answer 1

请看一下这个link。

它包含您要求的示例。下面是链接中的信息摘要。

第一步在 AndroidManifest.xml 中声明权限

<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

创建一个下载器类

public class Downloader {

    public static void DownloadFile(String fileURL, File directory) {
        try {

            FileOutputStream f = new FileOutputStream(directory);
            URL u = new URL(fileURL);
            HttpURLConnection c = (HttpURLConnection) u.openConnection();
            c.setRequestMethod("GET");
            c.setDoOutput(true);
            c.connect();

            InputStream in = c.getInputStream();

            byte[] buffer = new byte[1024];
            int len1 = 0;
            while ((len1 = in.read(buffer)) > 0) {
                f.write(buffer, 0, len1);
            }
            f.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

最后创建一个从互联网下载 PDF 文件的活动，

public class PDFFromServerActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        String extStorageDirectory = Environment.getExternalStorageDirectory()
        .toString();
        File folder = new File(extStorageDirectory, "pdf");
        folder.mkdir();
        File file = new File(folder, "Read.pdf");
        try {
            file.createNewFile();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        Downloader.DownloadFile("http://www.nmu.ac.in/ejournals/aspx/courselist.pdf", file);

        showPdf();
    }
    public void showPdf()
        {
            File file = new File(Environment.getExternalStorageDirectory()+"/pdf/Read.pdf");
            PackageManager packageManager = getPackageManager();
            Intent testIntent = new Intent(Intent.ACTION_VIEW);
            testIntent.setType("application/pdf");
            List list = packageManager.queryIntentActivities(testIntent, PackageManager.MATCH_DEFAULT_ONLY);
            Intent intent = new Intent();
            intent.setAction(Intent.ACTION_VIEW);
            Uri uri = Uri.fromFile(file);
            intent.setDataAndType(uri, "application/pdf");
            startActivity(intent);
        }
}