Android U盘SD卡插拔监听

现在有这个需求,就是U盘插入和拔出,这两个监听我能获取到,但是U盘或者SD卡已经插入了
然后再启动app,这个怎么监听,或者获取它的路径,因为不同的U盘或者SD卡的根目录不一样,
求大神指导!!!!!!万分感谢

/**
* 获取扩展存储路径，TF卡、U盘
*/
public static String getExternalStorageDirectory () {
String dir = new String();
try {
Runtime runtime = Runtime.getRuntime();
Process proc = runtime.exec("mount");
InputStream is = proc.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
String line;
BufferedReader br = new BufferedReader(isr);
while ((line = br.readLine()) != null) {
if (line.contains("secure")) continue;
if (line.contains("asec")) continue;

            if (line.contains("fat")) {
                String columns[] = line.split(" ");
                if (columns != null && columns.length > 1) {
                    dir = dir.concat(columns[1] + "\n");
                }
            } else if (line.contains("fuse")) {
                String columns[] = line.split(" ");
                if (columns != null && columns.length > 1) {
                    dir = dir.concat(columns[1] + "\n");
                }
            }
        }
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return dir;
}