Asynctask下载Bitmap图像时的存储位置

Question

我正在使用 AsyncTask 下载图像文件以保存在应用程序内部存储中，但我在模拟器设备管理器中找不到该文件。这是代码，你能告诉我它保存图像的确切位置吗

private class ImageDownloader extends AsyncTask<String,Void,Bitmap>{
    HttpURLConnection httpURLConnection;
    @Override
    protected Bitmap doInBackground(String... strings) {
        try {
            URL url = new URL(strings[0]);
            httpURLConnection = (HttpURLConnection) url.openConnection();
            InputStream inputStream = new BufferedInputStream(httpURLConnection.getInputStream());
            Bitmap temp = BitmapFactory.decodeStream(inputStream);
            return temp;

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            httpURLConnection.disconnect();
        }
        return null;
    }

Answer 1

在下面的示例中，我将使用冗长但详细的方法。这种方法可以让你手动给一个文件目录，让你保存到指定的目录或路径。

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;


/**
 * A utility that downloads a file from a URL.
 * @author www.codejava.net
 *
 */

public class HttpDownloadUtility {
    private static final int BUFFER_SIZE = 4096;
 
    /**
     * Downloads a file from a URL
     * @param fileURL HTTP URL of the file to be downloaded
     * @param saveDir path of the directory to save the file
     * @throws IOException
     */
    public static void downloadFile(String fileURL, String saveDir)
            throws IOException {
        URL url = new URL(fileURL);
        HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
        int responseCode = httpConn.getResponseCode();
 
        // always check HTTP response code first
        if (responseCode == HttpURLConnection.HTTP_OK) {
            String fileName = "";
            String disposition = httpConn.getHeaderField("Content-Disposition");
            String contentType = httpConn.getContentType();
            int contentLength = httpConn.getContentLength();
 
            if (disposition != null) {
                // extracts file name from header field
                int index = disposition.indexOf("filename=");
                if (index > 0) {
                    fileName = disposition.substring(index + 10,
                            disposition.length() - 1);
                }
            } else {
                // extracts file name from URL
                fileName = fileURL.substring(fileURL.lastIndexOf("/") + 1,
                        fileURL.length());
            }
 
            System.out.println("Content-Type = " + contentType);
            System.out.println("Content-Disposition = " + disposition);
            System.out.println("Content-Length = " + contentLength);
            System.out.println("fileName = " + fileName);
 
            // opens input stream from the HTTP connection
            InputStream inputStream = httpConn.getInputStream();
            String saveFilePath = saveDir + File.separator + fileName;
             
            // opens an output stream to save into file
            FileOutputStream outputStream = new FileOutputStream(saveFilePath);
 
            int bytesRead = -1;
            byte[] buffer = new byte[BUFFER_SIZE];
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
 
            outputStream.close();
            inputStream.close();
 
            System.out.println("File downloaded");
        } else {
            System.out.println("No file to download. Server replied HTTP code: " + responseCode);
        }
        httpConn.disconnect();
    }
}

Asynctask下载Bitmap图像时的存储位置

Storage location of Bitmap image when it is downloaded by Asynctask

java

android

mediastore

android-studio