How to store the downloaded file to sdcard and then retrieve it?

In my activity, I am downloading images from url. I want these images to be downloaded only for the first time. Later on when I visit this page, it should take the image from the sdcard. How can I do that? Can anyone help?

In manifest I have set permission:

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

The method which I use for downloading is:

public static Bitmap downloadFileFromUrl(String fileUrl){

        URL myFileUrl =null;  
        Bitmap imageBitmap = null;

        try {
            myFileUrl= new URL(fileUrl);
        } 
        catch (MalformedURLException e) {
            e.printStackTrace();
        }

        try {
            HttpURLConnection connection= (HttpURLConnection)myFileUrl.openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream is = connection.getInputStream();
            imageBitmap = BitmapFactory.decodeStream(is);

            //Below two lines I just tried out for saving to sd card.
            FileOutputStream out = new FileOutputStream(fileUrl);
            imageBitmap.compr开发者_如何转开发ess(Bitmap.CompressFormat.PNG, 90, out);
        } 
        catch (IOException e) {
            e.printStackTrace();
        }catch (Exception e) {
            e.printStackTrace();
        }

        return imageBitmap;
    }

Try this method

public void DownloadImage(String imageUrl)      
    {
        InputStream is = null;
        if((imageUrl == null) || (imageUrl.length() == 0) || (imageUrl == " "))
        {
            System.out.println("No need to download images now");
        }
        else
        {
            System.gc();


            String[] items; 

            String ImageName = null;

            URL myFileUrl =null; 
            Bitmap bmImg = null;

            String path = IMAGE_DOWNLOAD_PATH;

            FileOutputStream outStream = null;
            File file = new File(path);

            if(!file.exists())
            {
                file.mkdirs();  
            }

            File outputFile;
            BufferedOutputStream bos;

                try {   
                    myFileUrl= new URL(imageUrl.trim());

                    HttpURLConnection conn= (HttpURLConnection)myFileUrl.openConnection();
                    conn.setRequestMethod("GET");

                    conn.setDoInput(true);
                    conn.setConnectTimeout(20000);
                    conn.connect();

                    is = conn.getInputStream();


            } catch (MalformedURLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                    e.printStackTrace();
                }



                 ImageName = getImageName(imageUrl);

                 try {
                     outputFile = new File(file, ImageName);

                     if(outputFile.exists())                
                     {
                         System.out.println("No need to download image it already exist");
                         outputFile.delete();
                     }
                         outputFile.createNewFile();

                         outStream = new FileOutputStream(outputFile);
                         //bos = new BufferedOutputStream(outStream);
                         BufferedInputStream bis = new BufferedInputStream(is);

                            ByteArrayBuffer baf = new ByteArrayBuffer(50);

                            int current = 0;
                            while ((current = bis.read()) != -1) 
                            {
                                baf.append((byte) current);
                            }

                            outStream.write(baf.toByteArray());
                            outStream.close();




                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }   
        }

    }

and then to retrieve image from sdcard,

File extStore = Environment.getExternalStorageDirectory();
        String file_path = "/(folder name)/"+"(image name)".trim()+".extension".trim();

        String mypath = extStore + file_path;
        Bitmap bmp=BitmapFactory.decodeFile(mypath);
ImageView image = (ImageView) v.findViewById(R.id.image);
        image.setImageBitmap(bmp);

You should store somewhere what you've got in cache.

Or if your filename are unique you've to check than the file exist or not.

You have to write the data got from InputStream to specified SD card location ..