(转)获取系统剩余内存
原文：http://mingkg21.iteye.com/blog/605846

    private String getAvailMemory( ){          ActivityManager am = (ActivityManager) getSystemService( Context.ACTIVITY_SERVICE );          MemoryInfo mi = new MemoryInfo( );          am.getMemoryInfo( mi );          return Formatter.formatFileSize( context, mi.availMem );      }