ios - 手势结束后，实例变量将重置为零

Question

@IBAction func OnRightSwipeGesture(sender: UIPanGestureRecognizer) {
    let translated = sender.translationInView(self.view);

    let diffTrans = (translated.y - previouslyTranslated.y) / 75;
    sum += diffTrans;
    print(sum);
    colorWheel.transform = CGAffineTransformMakeRotation(sum);
    previouslyTranslated = translated;
}

在此函数中，我在每次调用后添加翻译差异。然而，当我将手指从设备上移开并尝试做出新手势后，总和重置为 0。总和在类的顶部声明，我非常困惑......

Answer 1

您应该检查手势识别器的状态，并且仅在变量等于UIGestureRecognizerStateChanged时更新变量。