Question

我正在尝试确定用户触摸屏幕的确切时间。我想出了这个（在我的ViewController中）：

var startTime: Date?

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    startTime = Date()
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    let endTime = Date()
    print(endTime.timeIntervalSince(startTime!))
}

似乎工作得很好。
这是否准确无误？有没有办法测试这是多么精确？

Answer 1

我会采用与你完成相同的结构。您的print(endTime.timeIntervalSince(startTime!))会为您打印出精确的Double值。

我会稍微调整一下，检查注释的解释：

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    startTime = Date()
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    // Don´t use startTime!, use if let instead
    if let startTime = startTime {
        // Use 2 decimals on your difference, or 3, or whatever suits your needs best
        let difference = String(format: "%.2f", Date().timeIntervalSince(startTime))
        print(difference)
    }
}

确定两次触摸之间的确切时间

1 个答案: