xcode 点击第一行时在 UITableView 中插入新行
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原文地址: http://stackoverflow.com/questions/15950069/
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Insert new row in UITableView when tapping first row
提问by Korg
I'm new to iOS development. Therefore it would be nice if your answer could be as detailed as possible. My problem is the following: I want the cell in my second section to always say "add new row". If you click this cell a new row should be added on top. My current code is
我是 iOS 开发的新手。因此，如果您的回答尽可能详细，那就太好了。我的问题如下：我希望第二部分中的单元格总是说“添加新行”。如果您单击此单元格，则应在顶部添加一个新行。我目前的代码是
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 2;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
if (section == 0) {
return 1;
}
else {
return [entries count];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *simpleTableIdentifier = @"Cell";
static NSString *todayTableIdentifier = @"Notification";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
UITableViewCell *todaycell = [tableView dequeueReusableCellWithIdentifier:todayTableIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];
}
NSString *entry;
if (indexPath.section == 0) {
entry = [notifications objectAtIndex:indexPath.row];
cell = todaycell;
} else {
entry = [entries objectAtIndex:indexPath.row];
}
cell.textLabel.text = entry;
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
int selectedRow = indexPath.row;
NSLog(@"row pressed %d", selectedRow);
NSArray *paths = [NSArray arrayWithObject:
[NSIndexPath indexPathForRow:2 inSection:2]];
if (selectedRow == 0)
{ [entries addObject:@"a new Entry"];
[[self tableView] insertRowsAtIndexPaths:paths
withRowAnimation:UITableViewRowAnimationTop];
}
else {
[[self tableView] deleteRowsAtIndexPaths:paths
withRowAnimation:UITableViewRowAnimationTop];
}
}
Unfortunately, my app keeps crashing.
不幸的是，我的应用程序不断崩溃。
2013-04-11 16:52:39.717 MyStore[12924:c07] *** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-2380.17/UITableView.m:861
2013-04-11 16:52:39.718 MyStore[12924:c07] *** Terminating app due to uncaught exception ' NSInternalInconsistencyException', reason: 'attempt to delete row 2 from section 2, but there are only 2 sections before the update'
*** First throw call stack:
(0x1faa012 0x13e7e7e 0x1fa9e78 0xb6d665 0xbb43c 0xca1f6 0xca271 0x5c6b 0xcb285 0xcb4ed 0xad55b3 0x1f69376 0x1f68e06 0x1f50a82 0x1f4ff44 0x1f4fe1b 0x1f047e3 0x1f04668 0x1bffc 0x21bd 0x20e5 0x1)
libc++abi.dylib: terminate called throwing an exception
回答by Rui Peres
That's normal, besides adding a new row (visually), you need to update your Data Source (the notifications array in this case). The UI is just the visualization of your Data Source. So:
这是正常的，除了添加新行（在视觉上）之外，您还需要更新您的数据源（在本例中为通知数组）。UI 只是数据源的可视化。所以：
[notifications addObject:@"a new Entry"];
[[self tableView] insertRowsAtIndexPaths:paths
withRowAnimation:UITableViewRowAnimationTop];
And when you delete:
当你删除时：
[notifications removeObjectAtIndex:indexPath.row];
[[self tableView] deleteRowsAtIndexPaths:paths
withRowAnimation:UITableViewRowAnimationTop];
