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;
          }
     }
}