UIView/Drawer 使用平移/滑动手势答案

【问题标题】：UIView/Drawer using Pan/Swipe GestureUIView/Drawer 使用平移/滑动手势
【发布时间】：2016-08-10 11:19:34
【问题描述】：

我正在尝试在滑动/平移手势上打开和关闭UIView，我从以下链接中找到了一些帮助 Link，和我想做的很接近。

我希望 UIView 默认打开 100 像素，用户可以使用手势滑动/平移 UIView 直到父 UIViewController 的 75% 并回到 100 像素，但它在下面的代码中闪烁。我希望UIView 的X 位置为0，这样它就可以像从顶部打开的抽屉一样。

- (void)viewDidLoad {
    [super viewDidLoad];
UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
  drawerView = [self.storyboard instantiateViewControllerWithIdentifier:@"drawerVC"];

    [drawerView.view setFrame:CGRectMake(0, -self.view.frame.size.height + 100, self.view.frame.size.width, self.view.frame.size.height * 0.75)];
    [drawerView.view setBackgroundColor:[UIColor redColor]];

    [drawerView.view addGestureRecognizer:panGesture];
}

-(void)move:(UIPanGestureRecognizer*)recognizer {

 recognizer.view.center = CGPointMake(self.view.frame.size.width/2,
                                         recognizer.view.center.y + translation.y);
    [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];




   if (recognizer.state == UIGestureRecognizerStateEnded) {

        CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));
        CGFloat slideMult = magnitude / 200;
        NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);

        float slideFactor = 0.1 * slideMult; // Increase for more of a slide
        CGPoint finalPoint = CGPointMake(0,
                                         recognizer.view.center.y + (velocity.y * slideFactor));
        finalPoint.x = 0;
        finalPoint.y = MIN(MAX(finalPoint.y, 0), drawerView.view.frame.size.height*.75);


        if (fabs(recognizer.view.frame.origin.y) >= fabs(yOffset))
        {
            return;
        }
        NSLog(@"ended %f",finalPoint.y);
        if (finalPoint.y < recognizer.view.frame.size.height/2) {
          //  [self movePanelToOriginalPosition];

        }
        else{
            [self movePanelToCenterPosition];
        }


    }
}

-(void)movePanelToCenterPosition {
    [UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseIn animations:^{
        drawerView.view.frame = CGRectMake(0, 0, drawerView.view.frame.size.width, drawerView.view.frame.size.height);
    }
                     completion:^(BOOL finished) {
                         // Stuff to do
                     }];
}

如果 UIView 处于默认状态（100 像素）并且只能向下滑动到所需的 CGPoint，是否有任何东西可以阻止用户在顶部（向上）方向平移 UIView。

【问题讨论】：

标签： ios objective-c uiview uigesturerecognizer uiviewanimation

【解决方案1】：

在你的移动中：检查移动是否开始或正在进行的方法

else if (recognizer.state == UIGestureRecognizerStateBegin || Recognizer.state == UIGestureRecognizerStateChanged)" 并且在 if 视图中处于其极限。如果是这样，您可以禁用/重新启用手势识别器。这将取消平移.. .

- (void) move:(UIGestureRecognizer *)sender
{
    if(sender.state == UIGestureRecognizerStateBegan || sender.state == UIGestureRecognizerStateChanged)
    {
        BOOL shouldEnablePan = NO; // TODO: do some logic here to figure out if you want to allow pan

        if(!shouldEnablePan && [sender isKindOfClass:[UIPanGestureRecognizer class]])
        {
            sender.enabled = NO;
            sender.enabled = YES;
        }

    } else ...
}

【讨论】：