Question

如果tableView中没有结果，我想显示警告。我使用如下所示的numberOfRowsInSection，但警报未显示。我还删除了if语句来检查计数，以防它出现问题。有谁知道为什么没有显示警报？任何帮助都会很棒。谢谢！

if ([self.listItems count] == 0)




- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

if (tableView == self.searchDisplayController.searchResultsTableView) {
    return [self.filteredListItems count];
}

else {
    return [self.listItems count]; 
    if ([self.listItems count] == 0) {

    //CALL ALERT HERE    
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"No Results" message:@"No 
    results were found" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
    [alert show];

    }    
    }
}

Answer 1

它没有显示，因为您在显示警告之前返回：

else {
    return [self.listItems count]; 
...

Answer 2

看到问题就在这一行return [self.listItems count]; 理由是你的执行不会超越这个。将其更改为：

else 
{
    if ([self.listItems count] == 0) 
    {
         //CALL ALERT HERE    
         UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"No Results" message:@"No 
         results were found" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
         [alert show];
         return;
    }
    return [self.listItems count]; 
}

Answer 3

检查条件后写入return语句。

   if ([self.listItems count] == 0) {

    //CALL ALERT HERE    
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"No Results" message:@"No 
    results were found" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
    [alert show];

    }  
return [self.listItems count];

如果tableView numberOfRowsInSection == 0，则显示警报

3 个答案: