我的xCode应用程序有问题。
我的申请是关于记录结果的。因此，项目值应为正。我试图防止在选择项目时记录负值或零值，但是我的代码无法正常工作。
这是我记录项目的代码
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"Outcome Item Value" message:@"Please enter an outcome item value" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK", nil];
alert.alertViewStyle = UIAlertViewStylePlainTextInput;
[alert show];
}
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 0) {
}
else
{
OutcomeItem* newOutcomeItem = [NSEntityDescription insertNewObjectForEntityForName:@"OutcomeItem" inManagedObjectContext:self.managedObjectContext];
newOutcomeItem.outcomeName = self.selectedOutcomeItem.outcomeName;
newOutcomeItem.outcomeValue = [NSNumber numberWithDouble:[[alertView textFieldAtIndex:0].text doubleValue]];
if (newOutcomeItem.outcomeValue <= 0) {
NSLog(@"Invalid Value");
[self.navigationController popViewControllerAnimated:YES];
}
else
{
[self.delegate addOutcomeItem:newOutcomeItem];
[self.navigationController popViewControllerAnimated:YES];
}
}
}
我的OutcomeItem.h是
#import<Foundation/Foundation.h>
#import<CoreData/CoreData.h>
@class OutcomeRecord;
@interface OutcomeItem : NSManagedObject
@property (nonatomic, retain) NSString *outcomeName;
@property (nonatomic, retain） NSNumber *outcomeValue;
@property (nonatomic, retain) OutcomeRecord *outcomeRecord;
@end;
现“OutcomeItem.m”为
#import "OutcomeItem.h"
#import "OutcomeRecord.h"
@implementation OutcomeItem
@dynamic outcomeName;
@dynamic outcomeValue;
@dynamic outcomeRecord;
@end
添加结果项的方法是
-(void)addOutcomeItem:(OutcomeItem *)outcomeItem
{
[self.currentOutcomeRecord addOutcomeItemsObject:outcomeItem];
self.outcomeRecordItemList = [self.currentOutcomeRecord.outcomeItems allObjects];
[self.tableView reloadData];
NSError* error;
if (![self.managedObjectContext save:&error]) {
NSLog(@"Could not save outcome item insertion:\n%@", error.userInfo);
}
}
最佳答案
我发现了问题。您需要从NSNumber强制转换为doubleValue。
NSNumber *outcomeValueX = [NSNumber numberWithDouble:[[alertView textFieldAtIndex:0].text doubleValue]];
if (outcomeValueX.doubleValue <= 0) {
NSLog(@"Invalid Value");
}
理想情况下，我将尝试使用UITextFieldDelegate验证到您的UITextField，并实现textField:shouldChangeCharactersInRange:replacementString。
看到这里:How to Test Character Input to UITextField as the User Enters Characters and Prevent Invalid Characters
在验证值之前，我也不会添加新的resultItem。