基本思路
当识别到press 手势的时候对cell原有的view 截图获得snapview，并隐藏原有view，动画都设置在snapview上面。long Press位置移动时，snapview的position随着移动，如果long Press手势结束时，其位置在距离cell边缘的一定范围内，则删除此cell，否则，删除snapview，原有view hidden = NO，恢复原样。
在cell中添加long press guestur recognizer
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPressGuesture:)];
[self.contentView addGestureRecognizer:longPress];
guesture recognizer的方法
- (void)handleLongPressGuesture:(UILongPressGestureRecognizer *)guesture {
CGPoint startPoint;
switch (guesture.state) {
//手势开始
case UIGestureRecognizerStateBegan:
{
NSLog(@"longpress started");
//获得截图
snapView = [_containerView snapshotViewAfterScreenUpdates:NO];
//叶神原文中重设了锚点，我没有
// snapView.layer.anchorPoint = CGPointMake(startPoint.x/snapView.layer.frame.size.width-0.1, startPoint.y/snapView.layer.frame.size.height-0.1);
snapView.frame = _containerView.frame;
snapView.transform = CGAffineTransformMakeRotation(M_PI/6);
startPoint = [guesture locationInView:self.contentView];
[self.contentView addSubview:snapView];
//隐藏原有view
_shadowView.hidden = YES;
_containerView.hidden = YES;
break;
}
//手势移动
case UIGestureRecognizerStateChanged: {
NSLog(@"longpress changed");
CGPoint changedPoint = [guesture locationInView:self.contentView];
//一开始把snapView设为了局部变量，这个动画不管用，将snapView改为全局变量就可以了。为啥嗯？
[UIView animateWithDuration:0.5 animations:^{
snapView.layer.position = changedPoint;
}];
break;
}
//手势结束
case UIGestureRecognizerStateEnded: {
NSLog(@"longpress ended");
CGPoint endedPoint = [guesture locationInView:self.contentView];
//设定删除边界，超过则删除
if (endedPoint.x > self.contentView.bounds.size.width - 50 ) {
if (_cellBlock) {
_cellBlock(YES, _cellIndex);
}
}
else {
if (_cellBlock) {
_cellBlock(NO, _cellIndex);
}
}
//手势结束后收拾cell view，原先隐藏的view再显示，snapview移除，此处无论是否删除cell，都会移除snapview并显示原先的view。
[snapView removeFromSuperview];
_containerView.hidden = NO;
_shadowView.hidden = NO;
}
default:
break;
}
删除cell的回调函数
在tableView的 cell for row at indexpath 代理方法中实现，如果确认删除，则处理datasource并执行delete row at index path 方法。
cell.cellBlock = ^(BOOL isDelete, NSIndexPath *index){
if (isDelete) {
[_allCityData removeObjectAtIndex:index.row];
[_cityList removeObjectAtIndex:index.row];
[self saveToNSUserDefault];
//deleteRowAtIndexPath, withRowAnimation 此方法决定删除cell的动画样式
[self.tableView deleteRowsAtIndexPaths:@[index] withRowAnimation:UITableViewRowAnimationRight];
//删除内容后reload data;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self.tableView reloadData];});
}
};
