Android开发中的内存读写一些工具类

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**在我们实际开发过程中经常会遇到关于手机内存的管理，比如说读取内存卡，下载图片、音乐、视频等等。每次使用的时候比较麻烦，下面这是一个关于手机内存的封装类，大家可以借鉴下：**

    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卡的跟路径    public static String getSDCardBaseDir() {        if (isSDCardMounted()) {            return Environment.getExternalStorageDirectory().getAbsolutePath();        }        return "";    }    // 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());            int count = fs.getBlockCount();            int size = fs.getBlockSize();            return count * size / 1024 / 1024;        }        return 0;    }    // 获取SD卡的剩余空间大小，返回MB    public static long getSDCardFreeSize() {        if (isSDCardMounted()) {            StatFs fs = new StatFs(getSDCardBaseDir());            int count = fs.getFreeBlocks();            int size = fs.getBlockSize();            return count * size / 1024 / 1024;        }        return 0;    }    // 获取SD卡的可用空间大小，返回MB    public static long getSDCardAvailableSize() {        if (isSDCardMounted()) {            StatFs fs = new StatFs(getSDCardBaseDir());            int count = fs.getAvailableBlocks();            int size = fs.getBlockSize();            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(Environment.DIRECTORY_MOVIES);            // Log.i("SDCardHelper", "--->" + file.getAbsolutePath());            try {                bos = new BufferedOutputStream(new FileOutputStream(new File(                        file, fileName)));                bos.write(data);                bos.flush();                return true;            } catch (Exception e) {                e.printStackTrace();            } finally {                try {                    if (bos != null) {                        bos.close();                    }                } catch (IOException e) {                    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 {                    if (bos != null) {                        bos.close();                    }                } catch (IOException e) {                    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 {                    if (bos != null) {                        bos.close();                    }                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return false;    }    // 往SD卡的私有Cache目录下保存文件    public static boolean saveFileToSDCardPrivateCacheDir(InputStream data, String fileName, Context context) {        BufferedInputStream bis = null;        BufferedOutputStream bos = null;        if (isSDCardMounted()) {            File file = context.getExternalCacheDir();            try {                bis = new BufferedInputStream(data);                bos = new BufferedOutputStream(new FileOutputStream(new File(                        file, fileName)));                byte[] buffer = new byte[1024*8];                int c=0;                while((c=bis.read(buffer))!=-1) {                    bos.write(buffer, 0 ,c);                    bos.flush();                }                return true;            } catch (Exception e) {                e.printStackTrace();            } finally {                try {                    if (bis != null) {                        bis.close();                    }                    if (bos != null) {                        bos.close();                    }                } catch (IOException e) {                    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();            }            try {                bos = new BufferedOutputStream(new FileOutputStream(new File(                        file, fileName)));                bos.write(data);                bos.flush();                return true;            } catch (Exception e) {                e.printStackTrace();            } finally {                try {                    if (bos != null) {                        bos.close();                    }                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return false;    }    // 从SD卡获取文件    public static byte[] loadFileFromSDCard(String filePath) {        BufferedInputStream bis = null;        ByteArrayOutputStream baos = new ByteArrayOutputStream();        try {            bis = new BufferedInputStream(new FileInputStream(                    new File(filePath)));            byte[] buffer = new byte[1024 * 8];            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 {                if (bis != null) {                    bis.close();                }                if (baos != null) {                    baos.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }        return null;    }    // 获取SD卡公有目录的路径    public static String getSDCardPublicDir(String type) {        return Environment.getExternalStoragePublicDirectory(type)                .getAbsolutePath();    }    // 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();    }}

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