Question

我想从url下载图片并存储在sdcard的文件夹中。
如果文件夹不存在，请创建文件夹并保存。
但是它给出以下例外：

java.io.FileNotFoundException: /mnt/sdcard (Is a directory)

Answer 1

信息很清楚。 / mnt / sdcard 是一个目录而不是一个文件。您需要创建写入非目录路径的 FileOutputStream 。

例如：

//Setting up cache directory to store the image
File cacheDir=new File(context.getCacheDir(),"cache_folder");

// Check if cache folder exists, otherwise create folder. 
if(!cacheDir.exists())cacheDir.mkdirs();

// Setting up file to write the image to. 
File f=new File(cacheDir, "img.png");

// Open InputStream to download the image. 
InputStream is=new URL(url).openStream();

// Set up OutputStream to write data into image file. 
OutputStream os = new FileOutputStream(f);

HelperUtil.CopyStream(is, os);

...



/**
 * Copy all data from InputStream and write using OutputStream
 * @param is InputStream
 * @param os OutputStream
 */
public static void CopyStream(InputStream is, OutputStream os)
{
    final int buffer_size=1024;
    try
    {
        byte[] bytes=new byte[buffer_size];
        for(;;)
        {
          int count=is.read(bytes, 0, buffer_size);
          if(count==-1)
              break;
          os.write(bytes, 0, count);
        }
    }
    catch(Exception ex){}
}

Answer 2

尝试这样的事情

String image_URL="http://chart.apis.google.com/chart?chs=200x200&cht=qr&chl=http%3A%2F%2Fandroid-er.blogspot.com%2F";

String extStorageDirectory;
File file;
Bitmap bm;
if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED)){
        file=new File(android.os.Environment.getExternalStorageDirectory(),"Your FolderName");
        extStorageDirectory = Environment.getExternalStorageDirectory().toString();
  }else{
        file=YourActivity.this.getCacheDir();
 }
if(!file.exists())
  file.mkdirs();


  extStorageDirectory+="Your FolderName/yourimagename.PNG";
  File imageFile = new File(extStorageDirectory);

  Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
  if(bitmap!=null){
  imageview.setImageBitmap(bitmap);
  }else{
    extStorageDirectory = Environment.getExternalStorageDirectory().toString();
    BitmapFactory.Options bmOptions;
    bmOptions = new BitmapFactory.Options();
    bmOptions.inSampleSize = 1;
    bm = LoadImage(image_URL, bmOptions);
    imageview.setImageBitmap(bm);

    OutputStream outStream = null;
    file=new File(android.os.Environment.getExternalStorageDirectory(),"Your FolderName");

    file=new File(extStorageDirectory, "Your FolderName/yourimagename.PNG");
     try {
        outStream = new FileOutputStream(file);
        bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
        outStream.flush();
        outStream.close();



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

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

      }
  }

其中方法为

private Bitmap LoadImage(String URL, BitmapFactory.Options options)
 {      
  Bitmap bitmap = null;
  InputStream in = null;      
    try {
      in = OpenHttpConnection(URL);
      bitmap = BitmapFactory.decodeStream(in, null, options);
      in.close();
    } catch (IOException e1) {
   }
  return bitmap;              
}

 private InputStream OpenHttpConnection(String strURL) throws IOException{
    InputStream inputStream = null;
    URL url = new URL(strURL);
    URLConnection conn = url.openConnection();

  try{
   HttpURLConnection httpConn = (HttpURLConnection)conn;
   httpConn.setRequestMethod("GET");
   httpConn.connect();

    if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
       inputStream = httpConn.getInputStream();
      }
  }catch (Exception ex){ 
       Log.e("error",ex.toString());
       }
  return inputStream;
 }

Answer 3

尝试保存图片时，您提供了错误的路径。你似乎使用“/ mnt / sdcard”，而它应该是“/mnt/sdcard/image.jpg”

Answer 4

BitmapFactory.Options bmOptions;
        bmOptions = new BitmapFactory.Options();
        bmOptions.inSampleSize = 1;
        bm = LoadImage(image_url, bmOptions);
        extStorageDirectory = Environment.getExternalStorageDirectory()
                .toString() + "/image_folder";

        OutputStream outStream = null;

        File wallpaperDirectory = new File(extStorageDirectory);
        wallpaperDirectory.mkdirs();
        File outputFile = new File(wallpaperDirectory, "image.PNG");

        try {
            outStream = new FileOutputStream(outputFile);
        } catch (FileNotFoundException e1) {
            e1.printStackTrace();
        }


        try {
            bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
            outStream.flush();
            outStream.close();


        } catch (FileNotFoundException e) {
            e.printStackTrace();

        } catch (IOException e) {
            e.printStackTrace();
        }
  private Bitmap LoadImage(String URL, BitmapFactory.Options options) {
Bitmap bitmap = null;
InputStream in = null;
try {
    in = OpenHttpConnection(URL);
    bitmap = BitmapFactory.decodeStream(in, null, options);
    in.close();
} catch (IOException e1) {
}
return bitmap;
 }

  private InputStream OpenHttpConnection(String strURL) throws IOException {
InputStream inputStream = null;
URL url = new URL(strURL);
URLConnection conn = url.openConnection();

try {
    HttpURLConnection httpConn = (HttpURLConnection) conn;
    httpConn.setRequestMethod("GET");
    httpConn.connect();

    if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
        inputStream = httpConn.getInputStream();
    }
} catch (Exception ex) {
}
return inputStream;
}

Answer 5

尝试这个，如果它存在，将返回外部存储器，否则它将返回手机存储器目录。构造函数将Context和要创建的文件夹的名称作为参数。并尝试这个链接，它是你需要的相当不错的东西。 Image Loader

public class FileCache {

private File cacheDir;
private String applicationDirectory = Config.applicationMainFolder;

public FileCache(Context context, String folderName){
    //Find the dir to save cached images
    if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
        cacheDir=new File(context.getExternalFilesDir(null), applicationDirectory + folderName);
    else
        cacheDir = new File(context.getCacheDir(), applicationDirectory + folderName);
    if(!cacheDir.exists())
        cacheDir.mkdirs();
}

public File getFile(String url){
    String filename=String.valueOf(url.hashCode());
    File f = new File(cacheDir, filename);
    return f;
}

public void clear(){
    File[] files=cacheDir.listFiles();
    if(files==null)
        return;
    for(File f:files)
        f.delete();
}
}

Answer 6

使用此

if(Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
        File file=new File(Environment.getExternalStorageDirectory()+path);  

        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG,100, bytes);
        byte b[] = bytes.toByteArray();
        try
        {
            FileOutputStream fos = new FileOutputStream(file);
            fos.write(b);
            fos.flush();
            fos.close();

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

    }

路径将是sdcard中的文件夹，而位图是图像的对象

下载图像并存储在sdcard文件夹中

6 个答案: