Android内部存储与外部存储的文件操作类

 public class SDCardHelper {

      // 判断SD卡是否被挂载
      public static boolean isSDCardMounted() {
          // return Environment.getExternalStorageState().equals("mounted");
          return Environment.getExternalStorageState().equals(
          Environment.MEDIA_MOUNTED);
     }

     // 获取SD卡的根目录
     public static String getSDCardBaseDir() {
          if (isSDCardMounted()) {
                return Environment.getExternalStorageDirectory().getAbsolutePath();
          }
          return null;
     }

     // 获取SD卡的完整空间大小，返回MB
     public static long getSDCardSize() {
          if (isSDCardMounted()) {
               StatFs fs = new StatFs(getSDCardBaseDir());
               long count = fs.getBlockCountLong();
               long size = fs.getBlockSizeLong();
               return count * size / 1024 / 1024;
          }
          return 0;
     }

     // 获取SD卡的剩余空间大小
     public static long getSDCardFreeSize() {
          if (isSDCardMounted()) {
                StatFs fs = new StatFs(getSDCardBaseDir());
                long count = fs.getFreeBlocksLong();
                long size = fs.getBlockSizeLong();
                return count * size / 1024 / 1024;
          }
          return 0;
     }

     // 获取SD卡的可用空间大小
     public static long getSDCardAvailableSize() {
          if (isSDCardMounted()) {
                StatFs fs = new StatFs(getSDCardBaseDir());
                long count = fs.getAvailableBlocksLong();
                long size = fs.getBlockSizeLong();
                return count * size / 1024 / 1024;
          }
          return 0;
     }

     // 往SD卡的公有目录下保存文件
     public static boolean saveFileToSDCardPublicDir(byte[] data, String type, String fileName) {
          BufferedOutputStream bos = null;
          if (isSDCardMounted()) {
                File file = Environment.getExternalStoragePublicDirectory(type);
                try {
                     bos = new BufferedOutputStream(new FileOutputStream(new File(file, fileName)));
                     bos.write(data);
                     bos.flush();
                     return true;
                } catch (Exception e) {
                     e.printStackTrace();
                } finally {
                     try {
                           bos.close();
                     } catch (IOException e) {
                           // TODO Auto-generated catch block
                           e.printStackTrace();
                     }
                }
           }
           return false;
      }

      // 往SD卡的自定义目录下保存文件
      public static boolean saveFileToSDCardCustomDir(byte[] data, String dir, String fileName) {
           BufferedOutputStream bos = null;
           if (isSDCardMounted()) {
                 File file = new File(getSDCardBaseDir() + File.separator + dir);
                 if (!file.exists()) {
                       file.mkdirs();// 递归创建自定义目录
                 }
                 try {
                       bos = new BufferedOutputStream(new FileOutputStream(new File(file, fileName)));
                       bos.write(data);
                       bos.flush();
                       return true;
                 } catch (Exception e) {
                       e.printStackTrace();
                 } finally {
                       try {
                             bos.close();
                       } catch (IOException e) {
                             // TODO Auto-generated catch block
                             e.printStackTrace();
                       }
                 }
            }
            return false;
      }

      // 往SD卡的私有Files目录下保存文件
      public static boolean saveFileToSDCardPrivateFilesDir(byte[] data, String type, String fileName, Context context) {
          BufferedOutputStream bos = null;
          if (isSDCardMounted()) {
                File file = context.getExternalFilesDir(type);
                try {
                       bos = new BufferedOutputStream(new FileOutputStream(new File(file, fileName)));
                       bos.write(data);
                       bos.flush();
                       return true;
                } catch (Exception e) {
                       e.printStackTrace();
                } finally {
                       try {
                             bos.close();
                       } catch (IOException e) {
                             // TODO Auto-generated catch block
                             e.printStackTrace();
                       }
                }
           }
           return false;
      }

      // 往SD卡的私有Cache目录下保存文件
      public static boolean saveFileToSDCardPrivateCacheDir(byte[] data, String fileName, Context context) {
           BufferedOutputStream bos = null;
           if (isSDCardMounted()) {
                 File file = context.getExternalCacheDir();
                 try {
                       bos = new BufferedOutputStream(new FileOutputStream(new File(file, fileName)));
                       bos.write(data);
                       bos.flush();
                       return true;
                 } catch (Exception e) {
                       e.printStackTrace();
                 } finally {
                       try {
                             bos.close();
                       } catch (IOException e) {
                             // TODO Auto-generated catch block
                             e.printStackTrace();
                       }
                }
           }
           return false;
      }

      // 保存bitmap图片到SDCard的私有Cache目录
      public static boolean saveBitmapToSDCardPrivateCacheDir(Bitmap bitmap, String fileName, Context context) {
           if (isSDCardMounted()) {
                 BufferedOutputStream bos = null;
                 // 获取私有的Cache缓存目录
                 File file = context.getExternalCacheDir();

                 try {
                        bos = new BufferedOutputStream(new FileOutputStream(new File(file, fileName)));
                        if (fileName != null && (fileName.contains(".png") || fileName.contains(".PNG"))) {
                               bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
                        } else {
                               bitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
                        }
                        bos.flush();
                 } catch (Exception e) {
                        e.printStackTrace();
                 } finally {
                        if (bos != null) {
                             try {
                                  bos.close();
                             } catch (IOException e) {
                                  e.printStackTrace();
                             }
                        }
                  }
                  return true;
           } else {
                 return false;
           }
      }

      // 从SD卡获取文件
      public static byte[] loadFileFromSDCard(String fileDir) {
           BufferedInputStream bis = null;
           ByteArrayOutputStream baos = new ByteArrayOutputStream();

           try {
                 bis = new BufferedInputStream(new FileInputStream(new File(fileDir)));
                 byte[] buffer = new byte[8 * 1024];
                 int c = 0;
                 while ((c = bis.read(buffer)) != -1) {
                      baos.write(buffer, 0, c);
                      baos.flush();
                 }
                 return baos.toByteArray();
           } catch (Exception e) {
                 e.printStackTrace();
           } finally {
                 try {
                      baos.close();
                      bis.close();
                 } catch (IOException e) {
                      e.printStackTrace();
                 }
           }
           return null;
      }

      // 从SDCard中寻找指定目录下的文件，返回Bitmap
      public Bitmap loadBitmapFromSDCard(String filePath) {
           byte[] data = loadFileFromSDCard(filePath);
           if (data != null) {
                Bitmap bm = BitmapFactory.decodeByteArray(data, 0, data.length);
                if (bm != null) {
                      return bm;
                }
           }
           return null;
      }

      // 获取SD卡公有目录的路径
      public static String getSDCardPublicDir(String type) {
           return Environment.getExternalStoragePublicDirectory(type).toString();
      }

      // 获取SD卡私有Cache目录的路径
      public static String getSDCardPrivateCacheDir(Context context) {
           return context.getExternalCacheDir().getAbsolutePath();
      }

      // 获取SD卡私有Files目录的路径
      public static String getSDCardPrivateFilesDir(Context context, String type) {
           return context.getExternalFilesDir(type).getAbsolutePath();
      }

      public static boolean isFileExist(String filePath) {
           File file = new File(filePath);
           return file.isFile();
      }

      // 从sdcard中删除文件
      public static boolean removeFileFromSDCard(String filePath) {
           File file = new File(filePath);
           if (file.exists()) {
                try {
                      file.delete();
                      return true;
                } catch (Exception e) {
                      return false;
                }
           } else {
                return false;
           }
      }
 }