我正在尝试在我的UITableViewController中实现一个UIPanGestureRecognizer,用于滑动以删除动画.与清除应用程序中使用的滑动删除类似,如果您向左或向右滑动UITableViewCell,则单元格会移动并被删除.
我已经尝试在我的UITableViewCell子类中实现它,但它似乎永远不会收到该事件.
这是我在UITableViewCell子类中放置的代码,用于尝试此功能.在我的init方法中
UIGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
recognizer.delegate = self;
[self addGestureRecognizer:recognizer];
然后处理它的方法：
- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer {
CGPoint translation = [gestureRecognizer translationInView:self.superview];
//might have to change view to tableView
//check for the horizontal gesture
if (fabsf(translation.x) > fabsf(translation.y)) {
return YES;
NSLog(@"Panning");
}
return NO;
}
- (void)handlePan:(UIPanGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateBegan) {
//if the gesture has just started record the center location
NSLog(@"handlePan");
_originalCenter = self.center; //Declared as a CGPoint at the top of my TableViewCell
}
if (recognizer.state == UIGestureRecognizerStateChanged) {
//translate the center (aka translate from the center of the cell)
CGPoint translation = [recognizer translationInView:self];
self.center = CGPointMake(_originalCenter.x + translation.x,_originalCenter.y);
// determine whether the item has been dragged far enough to delete/complete
}
if (recognizer.state == UIGestureRecognizerStateEnded) {
// the frame this cell would have had before being dragged
CGRect originalFrame = CGRectMake(0,self.frame.origin.y,self.bounds.origin.x,self.bounds.size.height);
[UIView animateWithDuration:0.2 animations:^{
self.frame = originalFrame;}
];
}
}
但是,细胞根本不会移动.不确定这里发生了什么
解决方法
如果您不希望单元格的滑动手势与表格视图滚动手势同时发生,则向您的单元格添加平移手势并使其成为委托：
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(doPan:)]; pan.delegate = self; [self addGestureRecognizer:pan];
并实现以下委托方法,仅在平移为水平时启动：
#pragma mark - UIGestureRecognizerDelegate
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
// note: we might be called from an internal UITableViewCell long press gesture
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
UIPanGestureRecognizer *panGestureRecognizer = (UIPanGestureRecognizer*)gestureRecognizer;
UIView *cell = [panGestureRecognizer view];
CGPoint translation = [panGestureRecognizer translationInView:[cell superview]];
// Check for horizontal gesture
if (fabs(translation.x) > fabs(translation.y))
{
return YES;
}
}
return NO;
}
Swift3 ..
override func awakeFromNib() {
super.awakeFromNib()
// do not use,say,layoutSubviews as layoutSubviews is called often
let p = UIPanGestureRecognizer(target: self,action: #selector(yourPan))
p.delegate = self
contentView.addGestureRecognizer(p)
}
}
override func gestureRecognizerShouldBegin(_ g: UIGestureRecognizer) -> Bool {
if (g.isKind(of: UIPanGestureRecognizer.self)) {
let t = (g as! UIPanGestureRecognizer).translation(in: contentView)
let verticalness = abs(t.y)
if (verticalness > 0) {
print("ignore vertical motion in the pan ...")
print("the event engine will >pass on the gesture< to the scroll view")
return false
}
}
return true
}
