继我之前的问题之后 moveRowAtIndexPath - Moving cells between sections
我已经能够在传统的moveRowAtIndexPath之间移动单元格，即：将Mark从Sales转移到Marketing。
然而现在我想更进一步，在tableview上添加longpress手势，让我可以在单元格上使用longpress移动单元格。
作为参考，我的表格是Employees在不同Departments工作的列表;模型是自定义的，但只是为名称保存简单的字符串。
我的行设置是这样的;
-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
return [_objects count];
}
-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
Department *department = [_objects objectAtIndex:section];
return [department.employees count];
}
我当前的moveRowAtIndexPath是：
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
if (fromIndexPath != toIndexPath ) {
Department *departmentFrom = [_objects objectAtIndex:fromIndexPath.section];
Department *departmentTo = [_objects objectAtIndex:toIndexPath.section];
Employee *employee = [departmentFrom.employees objectAtIndex:fromIndexPath.row];
[departmentFrom.employees removeObjectAtIndex:fromIndexPath.row];
[departmentTo.employees insertObject:employee atIndex:toIndexPath.row];
[tableView reloadData];
}
}
所以现在我在viewDidLoad，ala;
期间向表中添加了longpressUILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressGestureRecognized:)];
[self.tableView addGestureRecognizer:longPress];
然后终于拥有了我的longpress代码;
- (IBAction)longPressGestureRecognized:(id)sender {
UILongPressGestureRecognizer *longPress = (UILongPressGestureRecognizer *)sender;
UIGestureRecognizerState state = longPress.state;
CGPoint location = [longPress locationInView:self.tableView];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
static UIView *snapshot = nil; ///< A snapshot of the row user is moving.
static NSIndexPath *sourceIndexPath = nil; ///< Initial index path, where gesture begins.
switch (state) {
case UIGestureRecognizerStateBegan: {
if (indexPath) {
sourceIndexPath = indexPath;
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
// Take a snapshot of the selected row using helper method.
snapshot = [self customSnapshoFromView:cell];
// Add the snapshot as subview, centered at cell's center...
__block CGPoint center = cell.center;
snapshot.center = center;
snapshot.alpha = 0.0;
[self.tableView addSubview:snapshot];
[UIView animateWithDuration:0.25 animations:^{
// Offset for gesture location.
center.y = location.y;
snapshot.center = center;
snapshot.transform = CGAffineTransformMakeScale(1.05, 1.05);
snapshot.alpha = 0.98;
cell.alpha = 0.0;
} completion:^(BOOL finished) {
cell.hidden = YES;
}];
}
break;
}
case UIGestureRecognizerStateChanged: {
CGPoint center = snapshot.center;
center.y = location.y;
snapshot.center = center;
// Is destination valid and is it different from source?
if (indexPath && ![indexPath isEqual:sourceIndexPath]) {
// ... update data source.
// ... move the rows.
[self.tableView moveRowAtIndexPath:sourceIndexPath toIndexPath:indexPath];
// ... and update source so it is in sync with UI changes.
sourceIndexPath = indexPath;
}
break;
}
default: {
// Clean up.
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:sourceIndexPath];
cell.hidden = NO;
cell.alpha = 0.0;
[UIView animateWithDuration:0.25 animations:^{
snapshot.center = cell.center;
snapshot.transform = CGAffineTransformIdentity;
snapshot.alpha = 0.0;
cell.alpha = 1.0;
} completion:^(BOOL finished) {
sourceIndexPath = nil;
[snapshot removeFromSuperview];
snapshot = nil;
}];
break;
}
}
}
#pragma mark - Helper methods
/** @brief Returns a customized snapshot of a given view. */
- (UIView *)customSnapshoFromView:(UIView *)inputView {
// Make an image from the input view.
UIGraphicsBeginImageContextWithOptions(inputView.bounds.size, NO, 0);
[inputView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// Create an image view.
UIView *snapshot = [[UIImageView alloc] initWithImage:image];
snapshot.layer.masksToBounds = NO;
snapshot.layer.cornerRadius = 0.0;
snapshot.layer.shadowOffset = CGSizeMake(-5.0, 0.0);
snapshot.layer.shadowRadius = 5.0;
snapshot.layer.shadowOpacity = 0.4;
return snapshot;
}
可悲的是，它在试图移动细胞的UIGestureRecognizerStateChanged崩溃了;它与移动后/之前的数组不一致有关。
另外，我不确定我做得对吗？这种模式是否会在基于部门的部门和员工列表中发挥作用？
无论如何，我的查询是：如何将longpress手势添加到由部分组成的tableview单元格中，或者..我希望使用长按将Tom从Sales转移到Marketing。
鉴于上述代码，这可能吗？
编辑;
我得到的崩溃是：
＆＃39; NSInternalInconsistencyException＆＃39;，原因：＆＃39;无效更新：无效 第0节中的行数。包含在中的行数 更新后的现有部分（3）必须等于数量 更新前的该部分中包含的行（3），加号或减号 从该部分插入或删除的行数（插入0， 删除0）加上或减去移入或移出的行数 该部分（0移入，1移出）。＆＃39; ***首先抛出呼叫st
进一步更新：@ 2016年1月14日
原来接受的答案仍然让我崩溃。原因是假设正在进行交换;如果不是这样的话。
我通过重复删除项目然后重新添加项目来解决问题。
这张贴在下面;
case UIGestureRecognizerStateChanged: {
CGPoint center = snapshot.center;
center.y = location.y;
center.x = location.x;
snapshot.center = center;
// Is destination valid and is it different from source?
if (indexPath && ![indexPath isEqual:sourceIndexPath])
{
Department *departmentFrom = [_objects objectAtIndex:sourceIndexPath.section];
Department *departmentTo = [_objects objectAtIndex:indexPath.section];
[self.tableView beginUpdates];
Employee *employee = [departmentFrom.employees objectAtIndex:sourceIndexPath.row];
[departmentFrom.employees removeObjectAtIndex:sourceIndexPath.row];
[departmentTo.employees insertObject:employee atIndex:indexPath.row];
[self.tableView moveRowAtIndexPath:sourceIndexPath toIndexPath:indexPath];
[self.tableView endUpdates];
// ... and update source so it is in sync with UI changes.
sourceIndexPath = indexPath;
}
break;
}
我能看到的唯一问题是tableView：moveRowAtIndexPath和这段代码重复相同的代码。
但我可以稍后清理它。
由于
答案 0 :(得分：2)
case UIGestureRecognizerStateChanged: {
CGPoint center = snapshot.center;
center.y = location.y;
center.x = location.x;
snapshot.center = center;
// Is destination valid and is it different from source?
if (indexPath && ![indexPath isEqual:sourceIndexPath]) {
[self.stackTableView beginUpdates];
// ... update data source.
NSLog(@"exchanging");
[self.stackObjectArray exchangeObjectAtIndex:indexPath.section withObjectAtIndex:sourceIndexPath.section];
// ... move the rows.
NSLog(@"moving the rows");
[self.stackTableView moveRowAtIndexPath:indexPath toIndexPath:sourceIndexPath];
[self.stackTableView moveRowAtIndexPath:sourceIndexPath toIndexPath:indexPath];
NSLog(@"ending updates");
[self.stackTableView endUpdates];
// ... and update source so it is in sync with UI changes.
sourceIndexPath = indexPath;
}
break;
}
那你去吧！
您需要做的是立即阻止表视图更新，并使用beginUpdate和endUpdates同时执行所有更改。这样你就不会得到这样的错误。您还需要以相同的移动交换行，而不仅仅是移动它们。
我知道Ray Wenderlich的例子中他只提到移动的行，所以你走了！
http://www.raywenderlich.com/63089/cookbook-moving-table-view-cells-with-a-long-press-gesture