StorageManager是Android SDK中管理存储设备的一个类。其中的存储设备分内部存储和外部存储，外部存储可以有SDCard、U盘等其他挂载的外设。
StorageVolume代表的是一个设备信息的数据结构，里面包含了名称、路径、挂载状态等等信息。
以前获取设备列表的方法大多是通过反射获getVolumeList（）方法获取到StorageVolume[]数组，但是现在发现完全没有必要的，通过getStorageVolumes（）方法便可以获取到StorageVolume的集合。只是在取StorageVolume里面的字段的时候，像Path、ID这些属性的get方法是隐藏的，需要使用反射来获取。示例代码如下：
mStorageManager = getSystemService(StorageManager.class);List<StorageVolume> volumeList = mStorageManager.getStorageVolumes();for (StorageVolume volume : volumeList) {if (null != volume && volume.isRemovable()) {String label = volume.getDescription(this); //这个其实就是U盘的名称String status = volume.getState(); //设备挂载的状态，如:mounted、unmountedboolean isEmulated = volume.isEmulated(); //是否是内部存储设备boolean isRemovable = volume.isRemovable(); //是否是可移除的外部存储设备String mPath=""; //设备的路径try {Class myclass = Class.forName(volume.getClass().getName());Method getPath = myclass.getDeclaredMethod("getPath",null);getPath.setAccessible(true);mPath = (String) getPath.invoke(volume);Log.i(TAG,"name:"+label);Log.i(TAG,"status:"+status);Log.i(TAG,"isEmulated:"+isEmulated);Log.i(TAG,"isRemovable:"+isRemovable);Log.i(TAG,"mPath:"+mPath);} catch (ClassNotFoundException e) {e.printStackTrace();}catch (NoSuchMethodException e) {e.printStackTrace();}catch (InvocationTargetException e) {e.printStackTrace();}catch (IllegalAccessException e) {e.printStackTrace();}}}
当然，如果U盘通过转换器连接手机，我们可以写一个获取外置U盘存储路径的方法：
public String externalSDCardPath() {String externalSDCardPath = "";try {StorageManager storageManager = (StorageManager) getSystemService(Context.STORAGE_SERVICE);// 7.0才有的方法List<StorageVolume> storageVolumes = storageManager.getStorageVolumes();Class<?> volumeClass = Class.forName("android.os.storage.StorageVolume");Method getPath = volumeClass.getDeclaredMethod("getPath");Method isRemovable = volumeClass.getDeclaredMethod("isRemovable");getPath.setAccessible(true);isRemovable.setAccessible(true);for (int i = 0; i < storageVolumes.size(); i++) {StorageVolume storageVolume = storageVolumes.get(i);String mPath = (String) getPath.invoke(storageVolume);Boolean isRemove = (Boolean) isRemovable.invoke(storageVolume);if(isRemove){externalSDCardPath = mPath;}Log.i("tag2", "mPath is === " + mPath + "isRemoveble == " + isRemove);}}catch (Exception e){Log.i("tag2","e == "+e.getMessage());}return externalSDCardPath;}