Android 將檔案儲存到SD卡，從卡中取檔案，及刪除檔案

//儲存到SD卡    private static String sdState = Environment.getExternalStorageState();    private static String path = Environment.getExternalStorageDirectory().toString();    public static void saveBitmap(Bitmap bitmap,String imageName)    {      File file;     File PicName;     if(sdState.equals(Environment.MEDIA_MOUNTED))     {      //獲得sd卡根目錄      file = new File(path + "/Huai/TicketsPic");      if(!file.exists())      {       file.mkdirs();      }      PicName = new File(file, imageName);      try {       if(!PicName.exists())       {        PicName.createNewFile();       }    FileOutputStream fos = new FileOutputStream(PicName);    if(PicName.getName().endsWith(".png"))    {     bitmap.compress(CompressFormat.PNG, 100, fos);    }    else if(PicName.getName().endsWith(".jpg"))    {     bitmap.compress(CompressFormat.JPEG, 100, fos);    }    fos.flush();    fos.close();   } catch (FileNotFoundException e) {    e.printStackTrace();   } catch (IOException e) {    e.printStackTrace();   }          }    }   //從SD卡取    public static Bitmap getBitmap(String imageName)    {     Bitmap bitmap = null;     File imagePic;     if(sdState.equals(Environment.MEDIA_MOUNTED))     {            imagePic = new File(path + "/Huai/TicketsPic", imageName);      if(imagePic.exists())      {       try {        bitmap = BitmapFactory.decodeStream(new FileInputStream(imagePic));       } catch (FileNotFoundException e) {//        e.printStackTrace();       }      }     }  return bitmap;    }    ／／將SD卡檔案刪除    public static void  deleteFile(File file)    {     if(sdState.equals(Environment.MEDIA_MOUNTED))     {      if (file.exists())      {       if (file.isFile())       {        file.delete();       }       // 如果它是一個目錄       else if (file.isDirectory())       {        // 聲明目錄下所有的檔案 files[];        File files[] = file.listFiles();        for (int i = 0; i < files.length; i++)        { // 遍曆目錄下所有的檔案         deleteFile(files[i]); // 把每個檔案 用這個方法進行迭代        }       }       file.delete();      }     }    }