Qt使用小技巧

1，switch 使用：如果在case语句中定义变量 需要把 case 后面的代码用大括号括起来 否则会提示《 error: C2361: “default”标签跳过“time”的初始化操作》错误。

　　如 

    case libvlc_MediaPlayerTimeChanged:

        qDebug()<<"New time is"<<event->u.media_player_time_changed.new_time;

        int time = event->u.media_player_time_changed.new_time;

        emit obj->playCurrentTime(time/1000);

        break;

需要改为
　　

    case libvlc_MediaPlayerTimeChanged:{

        qDebug()<<"New time is"<<event->u.media_player_time_changed.new_time;

        int time = event->u.media_player_time_changed.new_time;

        emit obj->playCurrentTime(time/1000);

        break;}