我正在使用 PickerView 过滤现有数组（称为“Strains”），过滤后的数组称为“searchResults”。不知道为什么，但由于某种原因，我的应用程序说 searchResults 是空的（即使菌株已成功填充）。crash error我得到这样的：
Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 0 beyond bounds for empty array
知道为什么吗？代码如下。注意：“菌株”是从 MySQL 数据库中提取的。
PickerViewController.m
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;
{
return 3;
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
if (component == 0)
{
NSLog(@"you selected %@", [array1 objectAtIndex:row]);
}
if (component == 1)
{
NSLog(@"you selected %@", [array2 objectAtIndex:row]);
}
if (component == 2)
{
NSLog(@"you selected %@", [array3 objectAtIndex:row]);
}
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;
{
if (component == 0)
{
return [array1 count];
}
if (component == 1)
{
return [array2 count];
}
if (component == 2)
{
return [array3 count];
}
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;
{
if (component == 0)
{
return [array1 objectAtIndex:row];
}
if (component == 1)
{
return [array2 objectAtIndex:row];
}
if (component == 2)
{
return [array3 objectAtIndex:row];
}
}
- (void)populateArray1
{
array1 = [[NSMutableArray alloc] init];
[array1 addObject:@"Arthritis"];
[array1 addObject:@"Cancer"];
[array1 addObject:@"HIV"];
[array1 addObject:@"Migraines"];
[array1 addObject:@"Insomnia"];
}
- (void)populateArray2
{
array2 = [[NSMutableArray alloc] init];
[array2 addObject:@"Nausea"];
[array2 addObject:@"Pain"];
[array2 addObject:@"Appetite"];
[array2 addObject:@"Fever"];
[array2 addObject:@"Exhaustion"];
}
- (void)populateArray3
{
array3 = [[NSMutableArray alloc] init];
[array3 addObject:@"Oil"];
[array3 addObject:@"Plant"];
[array3 addObject:@"Edible"];
[array3 addObject:@"Powder"];
}
if ([[segue identifier] isEqualToString:@"pickerGo"])
{
NSLog(@"%@", Strains);
// Get reference to the destination view controller
PickerResultsTableViewController *PickerTableView = [(UINavigationController *)[segue destinationViewController] topViewController];
NSLog(@"%@", PickerTableView);
NSPredicate *ailmentPredicate = [NSPredicate predicateWithFormat:@"Ailment CONTAINS[c] %@", [array1 objectAtIndex:[pickerView selectedRowInComponent:0]]];
NSPredicate *actionPredicate = [NSPredicate predicateWithFormat:@"Action CONTAINS[c] %@", [array2 objectAtIndex:[pickerView selectedRowInComponent:1]]];
NSPredicate *ingestPredicate = [NSPredicate predicateWithFormat:@"Ingestion CONTAINS[c] %@", [array3 objectAtIndex:[pickerView selectedRowInComponent:2]]];
NSCompoundPredicate *resultPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:[NSArray arrayWithObjects: ailmentPredicate,actionPredicate,ingestPredicate, nil]];
searchResults = [Strains filteredArrayUsingPredicate:resultPredicate];
// Pass any objects to the view controller here, like...
[PickerTableView setSearchResults: [searchResults copy]];
NSLog(@"%@", searchResults);
}
}
表视图控制器.m
- (int)numberOfSectionsInTableView: (UITableView *)tableview
{
return 1;
}
- (int)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (tableView == PickerTableView) {
return [searchResults count];
} else {
return [Strains count];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *strainTableIdentifier = @"StrainTableCell";
StrainTableCell *cell = (StrainTableCell *)[tableView dequeueReusableCellWithIdentifier:strainTableIdentifier];
if (cell == nil)
cell = [[StrainTableCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:strainTableIdentifier];
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"StrainTableCell" owner:self options:nil];
cell = [nib objectAtIndex:0];
if (tableView == strainTableView) {
NSLog(@"Using the search results");
cell.titleLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Title"];
cell.descriptionLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Description"];
cell.ratingLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Rating"];
cell.ailmentLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Ailment"];
cell.actionLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Action"];
cell.ingestLabel.text = [[searchResults objectAtIndex:indexPath.row] objectForKey:@"Ingestion"];
NSLog(@"%@", searchResults);