ANDROID：如何将视频文件下载到 SD 卡？

Question

我在网站上有一个 .MP4 格式的视频文件，我希望用户能够通过单击链接将该视频下载到他们的 SD 卡上。有没有一种简单的方法可以做到这一点。我目前有这段代码，但它不起作用......不知道我做错了什么。感谢您的帮助！

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

import org.apache.http.util.ByteArrayBuffer;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class VideoManager extends Activity {
 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);}



        private final String PATH = "/sdcard/download/";  //put the downloaded file here


        public void DownloadFromUrl(String VideoURL, String fileName) {  //this is the downloader method
                try {
                        URL url = new URL("http://www.ericmoyer.com/episode1.mp4"); //you can write here any link
                        File file = new File(fileName);

                        long startTime = System.currentTimeMillis();
                        Log.d("VideoManager", "download begining");
                        Log.d("VideoManager", "download url:" + url);
                        Log.d("VideoManager", "downloaded file name:" + fileName);
                        /* Open a connection to that URL. */
                        URLConnection ucon = url.openConnection();

                        /*
                         * Define InputStreams to read from the URLConnection.
                         */
                        InputStream is = ucon.getInputStream();
                        BufferedInputStream bis = new BufferedInputStream(is);

                        /*
                         * Read bytes to the Buffer until there is nothing more to read(-1).
                         */
                        ByteArrayBuffer baf = new ByteArrayBuffer(50);
                        int current = 0;
                        while ((current = bis.read()) != -1) {
                                baf.append((byte) current);
                        }

                        /* Convert the Bytes read to a String. */
                        FileOutputStream fos = new FileOutputStream(PATH+file);
                        fos.write(baf.toByteArray());
                        fos.close();
                        Log.d("VideoManager", "download ready in"
                                        + ((System.currentTimeMillis() - startTime) / 1000)
                                        + " sec");

                } catch (IOException e) {
                        Log.d("VideoManager", "Error: " + e);
                }

        }
}

Answer 1

内存没有用完吗？
我想象视频文件非常大 - 您在写入文件之前对其进行缓冲。

我知道你的示例代码遍布互联网 - 但它不适合下载！
使用这个：

private final int TIMEOUT_CONNECTION = 5000;//5sec
private final int TIMEOUT_SOCKET = 30000;//30sec


            URL url = new URL(imageURL);
            long startTime = System.currentTimeMillis();
            Log.i(TAG, "image download beginning: "+imageURL);

            //Open a connection to that URL.
            URLConnection ucon = url.openConnection();

            //this timeout affects how long it takes for the app to realize there's a connection problem
            ucon.setReadTimeout(TIMEOUT_CONNECTION);
            ucon.setConnectTimeout(TIMEOUT_SOCKET);


            //Define InputStreams to read from the URLConnection.
            // uses 3KB download buffer
            InputStream is = ucon.getInputStream();
            BufferedInputStream inStream = new BufferedInputStream(is, 1024 * 5);
            FileOutputStream outStream = new FileOutputStream(file);
            byte[] buff = new byte[5 * 1024];

            //Read bytes (and store them) until there is nothing more to read(-1)
            int len;
            while ((len = inStream.read(buff)) != -1)
            {
                outStream.write(buff,0,len);
            }

            //clean up
            outStream.flush();
            outStream.close();
            inStream.close();

            Log.i(TAG, "download completed in "
                    + ((System.currentTimeMillis() - startTime) / 1000)
                    + " sec");5

Answer 2

切勿硬连线路径，尤其是到外部存储的路径。您的路径在许多设备上都是错误的。使用 Environment.getExternalStoragePath() 获取外部存储的根目录（可能为 /sdcard 或 /mnt/sdcard或其他）。

请务必使用从 Environment.getExternalStoragePath() 返回的 File 对象创建子目录。

最后，不要只说“但它不起作用”。我们不知道“但它不起作用”在您的情况下意味着什么。如果没有这些信息，就很难为您提供帮助。