前言

有获取外部SD卡存储空间的需求，但是某度出来的方法都千篇一律采用Environment类的getExternalStorageDirectory方法，但是此方法Deprecated。所以只能用其他方式。

1.StorageManager

获取StorageManager的实例

storageManager = (StorageManager)mContext.getSystemService(mContext.STORAGE_SERVICE);

2.获取存储卡路径

   private String[] getExtSDCardPath() {
        Log.d("SDRemount ","getExtSDCardPath");
        try {
            Class<?>[] paramClasses = {};
            Method getVolumePathsMethod = StorageManager.class.getMethod("getVolumePaths", paramClasses);
            getVolumePathsMethod.setAccessible(true);
            Object[] params = {};
            Object invoke = getVolumePathsMethod.invoke(storageManager, params);
            return (String[])invoke;
        } catch (NoSuchMethodException e1) {
            e1.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

3.检查挂载

返回挂载的SD卡路径，经多次测试，上一步获取到的路径全都为挂载的。其中第一个路径为：/storage/emulated/0，其为本身内部存储。所以当返回的路径个数大于1时，存在外部存储。

    public String[] sdCardRemounted()
    {
        Log.d("SDRemount ","sdCardRemounted checked");
        String[] data = getExtSDCardPath();
        List<String> list =new ArrayList<>();

        if (data.length > 0){
            for(String path : data){
                if(checkMounted(mContext,path)){
                    list.add(path);
                }
            }
        }

        int count = list.size();
        String[] result =new String[count];
        /*for (int i = 0;i < count; i++)
        {
            result[i]=list.get(i);
        }*/
        return  list.toArray(result);
    }

检查挂载：

    private boolean checkMounted(Context context, String mountPoint) {
        if (mountPoint == null) {
            Log.d("SDRemount ","mountPoint == null");
            return false;
        }
        //StorageManager storageManager = (StorageManager) context
                //.getSystemService(Context.STORAGE_SERVICE);
        try {
            Method getVolumeState = storageManager.getClass().getMethod(
                    "getVolumeState", String.class);
            String state = (String) getVolumeState.invoke(storageManager,
                    mountPoint);
            //Log.d("SDRemount ","SDCard path " + mountPoint +" and state " +state);
            StatFs statFs = new StatFs(mountPoint);
            long blockSize=statFs.getBlockSizeLong();
            long availableSize=statFs.getAvailableBlocksLong();
            long totalSize=statFs.getBlockCountLong();
            Log.d("SDRemount ","SDCard path " + mountPoint +" and state " +state +
                    " total size "+ totalSize*blockSize + " available size " + availableSize*blockSize);
            return Environment.MEDIA_MOUNTED.equals(state);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

4.根据路径获取存储空间

4.1 全部空间

    public long getTotalSize(String path){
        StatFs statFs = new StatFs(path);
        long blockSize=statFs.getBlockSizeLong();
        //long availableSize=statFs.getAvailableBlocksLong();
        long totalSize=statFs.getBlockCountLong();
        long total = blockSize * totalSize;
        Log.d("SDRemount ","SDCard path " + path +" total size "+ total);

        return total;
    }

4.2 可用空间

    public long getAvailableSize(String path){
        StatFs statFs = new StatFs(path);
        long blockSize=statFs.getBlockSizeLong();
        long availableSize=statFs.getAvailableBlocksLong();
        //long totalSize=statFs.getBlockCountLong();
        long total = blockSize * availableSize;
        Log.d("SDRemount ","SDCard path " + path +" total size "+ total);

        return total;
    }