java - 无法将图像保存到 SD 卡

Question

我尝试使用此代码下载图像并保存:在这一行中:

OutputStream os =new FileOutputStream(f);

我在模拟器上试了一下。我的应用程序得到异常，没有权限保存到这个路径:

java.io.FileNotFoundException: /mnt/sdcard/InterFlora/1221618532: open failed: EACCES (Permission denied)

我还添加了这一行:

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

这是代码:

   RetreiveImage extends AsyncTask<String, Void,Bitmap> {
           Item m_item;
           File f;

           public RetreiveImage(Item aItem , File aFile){
               m_item = aItem;
               f = File (m_Sdcard.getAbsolutePath() + "/myFolder");
           }

        @Override
        protected Bitmap doInBackground(String... params) {

        try
        {
            Bitmap bitmap=null;
            InputStream is=new URL(m_item.small).openStream();
            OutputStream os =new FileOutputStream(f);
            os.close();

            return bitmap;
        }
        catch (MalformedURLException e) {
            return null;
        } catch (IOException e) {
            return null;
        }
    }
}

编辑

File m_Sdcard = Environment.getExternalStorageDirectory();
File cacheDir =new File (m_Sdcard.getAbsolutePath() + "/MyFolder");
if(!cacheDir.exists())
cacheDir.mkdirs();

Answer 1

将此行添加到 manifest.xml 有效!!!

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