SDcard

 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.os.Environment;
 import android.os.StatFs;

 public class SDCardUtils {

     // 判断SDCard是否挂载
     public static boolean isSDCardMounted() {
         if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
             return true;
         }
         return false;
     }

     // 获得SDCard的根目录 如/storage/sdcard/
     public static String getSDCardBaseDir() {
         if (isSDCardMounted()) {
             File dir = Environment.getExternalStorageDirectory();
             return dir.getAbsolutePath();
         }
         return null;
     }

     // 获得SD卡的全部空间大小(单位:M)
     public static long getSDCardSize() {
         if (isSDCardMounted()) {
             String dir = getSDCardBaseDir();
             StatFs statFs = new StatFs(dir); // StatFs是C语言引入过来的
             long blockCount = statFs.getBlockCountLong(); // 有多少块
             long blockSize = statFs.getBlockSizeLong(); // 每块有多大
             return blockCount * blockSize / 1024 / 1024;
         }
         return 0;
     }

     // 获取SDCard空闲空间的大小(单位:M) (有多少空间还没被占用的)
     public static long getSDCardFreeSize() {
         if (isSDCardMounted()) {
             String dir = getSDCardBaseDir();
             StatFs statFs = new StatFs(dir); // StatFs是C语言引入过来的
             long freeBlockCount = statFs.getFreeBlocksLong(); // 空闲的块
             long blockSize = statFs.getBlockSizeLong(); // 每块有多大
             return freeBlockCount * blockSize / 1024 / 1024;
         }
         return 0;
     }

     // 获取SDCard可用空间的大小(单位:M) (有多少空间你可以使用的)
     public static long getSDCardAvailSize() {
         if (isSDCardMounted()) {
             String dir = getSDCardBaseDir();
             StatFs statFs = new StatFs(dir); // StatFs是C语言引入过来的
             long availBlockCount = statFs.getAvailableBlocksLong(); // 可用的块
             long blockSize = statFs.getBlockSizeLong(); // 每块有多大
             return availBlockCount * blockSize / 1024 / 1024;
         }
         return 0;
     }

     // 往SDCard公有目录下保存文件 (九大公有目录中的一个，具体由type指定) /storage/sdcard/{type}
     public static boolean saveData2SDCardPublicDir(byte[] data, String type, String filename) {
         if (isSDCardMounted()) {
             // 文件名:/storage/sdcard/Musics/111.txt
             // 文件名:getSDCardBaseDir()/{type}/{filename}
             String baseDir = getSDCardBaseDir();
             String file = baseDir + File.separator + type + "/" + filename;
             try {
                 OutputStream os = new FileOutputStream(file);
                 os.write(data);
                 os.close();
                 return true;
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         return false;
     }

     // 往SDCard的自定义目录中保存数据 /storage/sdcard/{dir}
     public static boolean saveData2SDCardCustomDir(byte[] data, String dir, String filename) {
         if (isSDCardMounted()) {
             // /storage/sdcard/{dir}
             // getSDCardBaseDir()/{dir}/{filename}
             String baseDir = getSDCardBaseDir(); // SDCard目录
             String path = baseDir + "/" + dir; // SDCard中自定义的目录
             // 如果path不存在的话 需要创建目录
             File customPath = new File(path);
             if (!customPath.exists()) {
                 customPath.mkdir();
             }
             String file = path + "/" + filename; // SDCard中自定义目录中的文件
             try {
                 OutputStream os = new FileOutputStream(file);
                 os.write(data);
                 os.close();
                 return true;
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }

         }
         return false;
     }

     // ：往SDCard的私有File目录下保存文件
     // /storage/sdcard/Android/data/包名/files/{type}/{filename}
     public static boolean saveData2SDCardPrivateFileDir(byte[] data, String type, String filename, Context context) {
         if (isSDCardMounted()) {
             // storage/sdcard/Android/data/包名/files/{type}/{filename}
             File path = context.getExternalFilesDir(type);
             if (!path.exists()) {
                 path.mkdir();
             }
             String file = path.getAbsolutePath() + "/" + filename; // 文件路径
             try {
                 OutputStream os = new FileOutputStream(file);
                 os.write(data);
                 os.close();
                 return true;
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         return false;
     }

     // 往SDCard的私有Cache目录下保存文件 /storage/sdcard/Android/data/包名/cache/{filename}
     public static boolean saveData2SDCardPrivateCacheDir(byte[] data, String filename, Context context) {
         if (isSDCardMounted()) {
             // storage/sdcard/Android/data/包名/cache/{filename}
             File path = context.getExternalCacheDir();
             if (!path.exists()) {
                 path.mkdir();
             }
             String file = path.getAbsolutePath() + "/" + filename;
             try {
                 OutputStream os = new FileOutputStream(file);
                 os.write(data);
                 os.close();
                 return true;
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         return false;
     }

     // 往SDCard的私有Cache目录下保存图像 /storage/sdcard/Android/data/包名/cache/{filename}  xxx.png xxx.jpg
     public static boolean saveBitmap2SDCardPrivateCacheDir(Bitmap bitmap,
             String filename, Context context) {
         if(isSDCardMounted()) {
             // 路径/storage/sdcard/Android/data/包名/cache/{filename}
             File path = context.getExternalCacheDir();
             if(!path.exists()) {
                 path.mkdir();
             }
             String file = path.getAbsolutePath() + "/" + filename; // bmp、jpg
             try {
                 OutputStream os = new FileOutputStream(file);
                 // 图片转换成byte[] 下面的代码代替os.write(...);
                 // 判断到底是哪种图片的格式(jpg、png)
                 if(filename.endsWith(".jpg") || filename.endsWith(".JPG")) {
                     bitmap.compress(Bitmap.CompressFormat.JPEG, 100, os);
                 } else if (filename.endsWith(".png") || filename.endsWith(".PNG")) {
                     bitmap.compress(Bitmap.CompressFormat.PNG, 100, os);
                 }
                 os.close();
                 return true;
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }

         return false;
     }

     // 从SDCard读取指定文件 /storage/sdcard/{filePath}
     public static byte[] loadFileFromSDCard(String filePath) {
         if(isSDCardMounted()) {
             // /storage/sdcard/{filePath}
             // getSDCardBaseDir()/{filePath}
             String path = getSDCardBaseDir();
             String file = path + "/" + filePath;
             try {
                 InputStream is = new FileInputStream(file);
                 ByteArrayOutputStream baos = new ByteArrayOutputStream();
                 byte[] buffer = new byte[1024];
                 int ret;
                 while(true) {
                     ret = is.read(buffer);
                     if(ret < 0) {
                         break;
                     }
                     baos.write(buffer, 0, ret);
                 }
                 return baos.toByteArray(); // 返回字节数组
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         return null;
     }

     // 从SDCard读取Bitmap并返回 /storage/sdcard/{filePath}
     public static Bitmap loadBitmapFromSDCard(String filePath) {
         if(isSDCardMounted()) {
             // 由于传入的参数已经是全路径了 因此不需要加上getSDCardBaseDir()
             try {
                 InputStream is = new FileInputStream(filePath);
                 byte[] buffer = new byte[1024];
                 ByteArrayOutputStream baos = new ByteArrayOutputStream();
                 int ret;
                 while(true) {
                     ret = is.read(buffer);
                     if(ret < 0) {
                         break;
                     }
                     baos.write(buffer, 0, ret);
                 }
                 byte[] data = baos.toByteArray();
                 return BitmapFactory.decodeByteArray(data, 0, data.length);
             } catch (FileNotFoundException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         return null;
     }
 }