moveRowAtIndexPath - 在节之间移动单元格 [英] moveRowAtIndexPath - Moving cells between sections
问题描述
在我的UITableView中我有这种关系
In my UITableView I have this said relationship
部门 - <员工（名称数组）
我为每个模型设置了自定义对象。
I have set up custom objects for each model.
在我的 moveRowAtIndexPath 中，我可以移动到特定的部分;但是如果我尝试在不同部分之间移动它会崩溃。
In my moveRowAtIndexPath, I can move in a specific section; however it crashes if I try to move it between sections.
我希望能够将Tom从Sales移动到Marketing
The idea being I want to be able to move "Tom" from "Sales" to "Marketing"
#pragma mark - UITableView delegate
-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
return [_objects count];
}
-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
Department *department = [_objects objectAtIndex:section];
return [department.employees count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CellId" forIndexPath:indexPath];
// Configure the cell...
Department *department = [_objects objectAtIndex:indexPath.section];
Employee *employee = [department.employees objectAtIndex:indexPath.row];
cell.textLabel.text = employee.name;
return cell;
}
-(NSString *) tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
Department *department = [_objects objectAtIndex:section];
return department.name;
}
- (BOOL) tableView: (UITableView *) tableView canEditRowAtIndexPath: (NSIndexPath *) indexPath
{
return YES;
}
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
if (fromIndexPath == toIndexPath ) return;
Department *department = [_objects objectAtIndex:fromIndexPath.section];
Employee *employee = [department.employees objectAtIndex:fromIndexPath.row];
[self.tableView beginUpdates];
[department.employees removeObjectAtIndex:fromIndexPath.row];
[department.employees insertObject:employee atIndex:toIndexPath.row];
[self.tableView endUpdates];
[tableView reloadData];
}
如何获得 moveRowAtIndexPath 允许我将员工从一个部门转移到另一个部门（或者更确切地说是一个部门）？
How do I get the moveRowAtIndexPath to allow me to move employees from one department to another (or rather one section to another)?
非常感谢
//崩溃;
*** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-2935.137/UITableView.m:1368
2015-02-20 20:51:15.772 Departments[999:90b] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (3) must be equal to the number of rows contained in that section before the update (2), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'
*** First throw call stack:
(
0 CoreFoundation 0x01a221e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x017a18e5 objc_exception_throw + 44
2 CoreFoundation 0x01a22048 +[NSException raise:format:arguments:] + 136
3 Foundation 0x013814de -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 116
4 UIKit 0x00539f63 -[UITableView _endCellAnimationsWithContext:] + 13402
5 UIKit 0x00549cea -[UITableView endUpdatesWithContext:] + 51
6 UIKit 0x00549d18 -[UITableView endUpdates] + 41
7 Departments 0x00003a48 -[ViewController tableView:moveRowAtIndexPath:toIndexPath:] + 664
8 UIKit 0x005573b4 -[UITableView _endReorderingForCell:wasCancelled:animated:] + 619
9 UIKit 0x006e0c4f -[UITableViewCell _grabberReleased:] + 73
10 UIKit 0x007d1a1b -[UITableViewCellReorderControl endTrackingWithTouch:withEvent:] + 58
11 UIKit 0x005641f1 -[UIControl touchesEnded:withEvent:] + 559
12 UIKit 0x004a2ddd -[UIWindow _sendTouchesForEvent:] + 852
13 UIKit 0x004a39d1 -[UIWindow sendEvent:] + 1117
14 UIKit 0x004755f2 -[UIApplication sendEvent:] + 242
15 UIKit 0x0045f353 _UIApplicationHandleEventQueue + 11455
16 CoreFoundation 0x019ab77f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
17 CoreFoundation 0x019ab10b __CFRunLoopDoSources0 + 235
18 CoreFoundation 0x019c81ae __CFRunLoopRun + 910
19 CoreFoundation 0x019c79d3 CFRunLoopRunSpecific + 467
20 CoreFoundation 0x019c77eb CFRunLoopRunInMode + 123
21 GraphicsServices 0x031ee5ee GSEventRunModal + 192
22 GraphicsServices 0x031ee42b GSEventRun + 104
23 UIKit 0x00461f9b UIApplicationMain + 1225
24 Departments 0x000046bd main + 141
25 libdyld.dylib 0x02ed5725 start + 0
26 ??? 0x00000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
推荐答案
您的问题是您操纵了数据模型，但是您没有告诉tableview您所做的更改。
Your problem is that you have manipulated the data model, but you haven't told the tableview about the changes you made.
因为你打电话给 beginUpdates / endUpdates tableview是期待一些变化，所以在 endUpdates 之后，它调用 numberOfRowsInSection - 返回答案'3' - 但它预计会有2 +0（因为你没有告诉它有关新行的信息）。
Because you call beginUpdates/endUpdates the tableview is expecting some changes, so after endUpdates it calls numberOfRowsInSection - which returns the answer '3' - but it is expecting 2+0 (because you didn't tell it about the new row).
你有几个选择：
1 - 使用 moveRowAtIndexPath：toIndexPath：
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
if (fromIndexPath != toIndexPath ) {
Department *department = [_objects objectAtIndex:fromIndexPath.section];
Employee *employee = [department.employees objectAtIndex:fromIndexPath.row];
[tableView beginUpdates];
[department.employees removeObjectAtIndex:fromIndexPath.row];
[department.employees insertObject:employee atIndex:toIndexPath.row];
[tableview moveRowAtIndexPath:fromIndexPath toIndexPath:toIndexPath];
[self.tableView endUpdates];
}
}
2 - 在没有 endUpdate
2 - Use reload without the beginUpdate/endUpdate
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
if (fromIndexPath != toIndexPath ) {
Department *department = [_objects objectAtIndex:fromIndexPath.section];
Employee *employee = [department.employees objectAtIndex:fromIndexPath.row];
[department.employees removeObjectAtIndex:fromIndexPath.row];
[department.employees insertObject:employee atIndex:toIndexPath.row];
[tableView reloadData];
}
}
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