就是利用反射原理。5.1 6.0 基本都一样。

8.1外置Sd卡路径

   public String getSdCardPath() {
       
       int TYPE_PUBLIC = 0;
       
       File file = null;
       
       String path = null;
       
       StorageManager mStorageManager = getSystemService(StorageManager.class);
       
       
       Class<?> mVolumeInfo = null;
       try {
           mVolumeInfo = Class.forName("android.os.storage.VolumeInfo");
       
           
           Method getVolumes = mStorageManager.getClass().getMethod(
                   "getVolumes");
           
           
           Method volType = mVolumeInfo.getMethod("getType");
           
           Method isMount = mVolumeInfo.getMethod("isMountedReadable");

           Method getPath = mVolumeInfo.getMethod("getPath");

           List<Object> mListVolumeinfo = (List<Object>) getVolumes
                   .invoke(mStorageManager);
           
     
           
           Log.d("getSdCardPath", "mListVolumeinfo.size="+mListVolumeinfo.size());
           
           for (int i = 0; i < mListVolumeinfo.size(); i++) {
               
               int mType = (Integer) volType.invoke(mListVolumeinfo.get(i));
               
               Log.d("getSdCardPath", "mType=" + mType);
               
               if (mType == TYPE_PUBLIC) {
                   boolean misMount = (Boolean) isMount.invoke(mListVolumeinfo.get(i));
                   Log.d("getSdCardPath", "misMount=" + misMount);
                   if (misMount) {
                       file = (File) getPath.invoke(mListVolumeinfo.get(i));
                       if (file != null) {
                           path = file.getAbsolutePath();
                           Log.d("getSdCardPath", "path=" + path);
                           return path;
                       }
                   }
               }

           }

       } catch (ClassNotFoundException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchMethodException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalAccessException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalArgumentException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvocationTargetException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       return "";
   }

7.0

private static String getStoragePath(Context mContext, boolean is_removale) {  

      StorageManager mStorageManager = (StorageManager) mContext.getSystemService(Context.STORAGE_SERVICE);
        Class<?> storageVolumeClazz = null;
        try {
            storageVolumeClazz = Class.forName("android.os.storage.StorageVolume");
            Method getVolumeList = mStorageManager.getClass().getMethod("getVolumeList");
            Method getPath = storageVolumeClazz.getMethod("getPath");
            Method isRemovable = storageVolumeClazz.getMethod("isRemovable");
            Object result = getVolumeList.invoke(mStorageManager);
            final int length = Array.getLength(result);
            for (int i = 0; i < length; i++) {
                Object storageVolumeElement = Array.get(result, i);
                String path = (String) getPath.invoke(storageVolumeElement);
                boolean removable = (Boolean) isRemovable.invoke(storageVolumeElement);
                if (is_removale == removable) {
                    return path;
                }
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
}

外置SD卡大小

String path="/storage/sdcard1";
public void volumeSizeTest2(boolean existed){
  if(existed){
           android.os.StatFs f=new  android.os.StatFs(path);
          long blockSize= f.getBlockSizeLong();
              long totalSize=f.getBlockCountLong();
        long availableBlocks=f.getAvailableBlocksLong();

        double sd1=(blockSize*totalSize*1.0)/1024/1024/1024;
        double sd2=(blockSize*availableBlocks*1.0)/1024/1024/1024;
                
            String totalSize1 = String.valueOf(sd1);
        String str1 = totalSize1.substring(0, 5);
                    
        String availableBlocks1 = String.valueOf(sd2);
        String str2 = availableBlocks1.substring(0, 5);
                
        mInfo.setText(getString(R.string.sdcard_freesize)+   str2+"GB"+"\n\n"+getString(R.string.sdcard_totalsize)
                    +str1+"GB");
        }else{
                mInfo.setText(getString(R.string.sdcard_tips_failed));
            }
      }