xcode UITableView 出现空单元格
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UITableView appears with empty cells
提问by Oleg
I have a problem displaying UITableView: Some cells are empty, and content in cells becomes visible only after scrolling (if empty cell scrolls out of the screen and then goes back). I Can't understand what might be the problem.
我在显示时遇到问题UITableView：某些单元格为空，并且单元格中的内容仅在滚动后才可见（如果空单元格滚动出屏幕然后返回）。我不明白可能是什么问题。
Here is my code:
这是我的代码：
- (void)viewDidLoad
{
[super viewDidLoad];
[self updateFilesList];
[tableView reloadData];
}
- (void) viewDidAppear:(BOOL)animated
{
animated = YES;
[self updateFilesList];
[self.tableView reloadData];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
[self.filesList retain];
NSString *title = [self.filesList objectAtIndex:indexPath.row];
title = [title stringByDeletingPathExtension];
title = [title lastPathComponent];
if (title.length >33) {
title = [title substringFromIndex:33];
}
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
[cell.imageView setImage:[UIImage imageNamed:@"oie_png-1.png"]];
cell.textLabel.text = title;
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
return cell;
}
Thank you in advance for your suggestions!
预先感谢您的建议！
采纳答案by adig
Well, you have the cell customization code that happens before you create the cell.
好吧，您拥有在创建单元格之前发生的单元格自定义代码。
Change it like this :
像这样改变它：
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
[self.filesList retain];
NSString *title = [self.filesList objectAtIndex:indexPath.row];
title = [title stringByDeletingPathExtension];
title = [title lastPathComponent];
if (title.length >33) {
title = [title substringFromIndex:33];
}
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// This part creates the cell for the firs time
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
// This part customizes the cells
[cell.imageView setImage:[UIImage imageNamed:@"oie_png-1.png"]];
cell.textLabel.text = title;
return cell;
}
回答by Jpellat
The problem is that you make
问题是你让
[cell.imageView setImage:[UIImage imageNamed:@"oie_png-1.png"]];
cell.textLabel.text = title;
before
前
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
change the order. What is happening is that the first time you execute the table View you never do the title before the alloc. When you reuse cell it works because the cell != nil
改变顺序。发生的事情是，第一次执行表视图时，您永远不会在分配之前执行标题。当您重用单元格时，它会起作用，因为单元格 != nil
回答by Lorenzo B
You need to put these lines
你需要把这些行
[cell.imageView setImage:[UIImage imageNamed:@"oie_png-1.png"]];
cell.textLabel.text = title;
after the if(){...}condition.
之后的if(){...}状态。
In the first pass cells are nil. Put those lines before the ifdoes nothing. This is why you see empty cells.
在第一次传递中，单元格为零。将这些行放在if什么都不做之前。这就是您看到空单元格的原因。
A simple question
一个简单的问题
Why do you call [self.filesList retain]?
你为什么打电话[self.filesList retain]？
Hope it helps.
希望能帮助到你。
