Question

我有一个oc版本

func locationManager(_ manager: CLLocationManager, didUpdateHeading newHeading: CLHeading) {        
    let trueHeading = newHeading.trueHeading
    let angle = Double.pi / 180 * trueHeading

    let dir = [ "N","NE","E","SE","S","SW","W","NW" ]
    let dir2=dir[(((trueHeading-22.5)/45.0)) as Int & 7]
}

然后我转换为swift版本

let dir2=dir[(((trueHeading-22.5)/45.0)) as Int & 7]

但它不起作用，有错误＆＃34;预期＆＃39;，＆＃39;分离器＆＃34;在这一行

<table id="post-table" class="table display-table table-striped table-
bordered" width="100%" cellspacing="0">
<thead>
<tr>
  <th>Class</th>
  <th>Published</th>
  <th>Quiz</th>
  <th>Create Quiz</th>
  <th>View Quiz</th>
</tr>
</thead>
<tbody>
<?php foreach ($allposts as $allpost) { ?>
<tr>
  <td><?php echo $grades->getGradename($allpost['grade_id']); ?></td>
  <td><?php echo $others->milliToTime($allpost['created_at']); ?></td>
  <td><?php echo $quiz->quizCount($allpost['post_id']); ?></td>
  <td>
    <a href="#" data-post-id='<?php echo $allpost['post_id']; ?>' class="create-quiz"><i class="fa fa-plus-circle" aria-hidden="true"></i></a>
  </td>
  <td><a href="/admin/quiz/allquiz.php?post_id=<?php echo $allpost['post_id'] ?>"><i class="fa fa-eye" aria-hidden="true"></i></a></td>
</tr>
<?php } ?>
</tbody>
</table>

Answer 1

你想要：

func compassDirection(for heading: CLLocationDirection) -> String? {
    if heading < 0 { return nil }

    let directions = ["N", "NE", "E", "SE", "S", "SW", "W", "NW"]
    let index = Int((heading + 22.5) / 45.0) & 7
    return directions[index]
}

注意，它是+，而不是-。

或者您可以使用rounded来避免混淆是否添加或减去22.5：

let index = Int((heading / 45).rounded()) % 8

然后您可以使用此compassDirection结果：

func locationManager(_ manager: CLLocationManager, didUpdateHeading newHeading: CLHeading) {
    guard let direction = compassDirection(for: newHeading.trueHeading) else {
        // handle lack of heading here
        return
    }

    // you can use `direction` here
}

Answer 2

试试这个let dir2=dir[Int((trueHeading - 22.5) / 45.0) & 7]

如何使用swift将方向度转换为文本？

2 个答案: