Question

我正在创建一个学生索引应用程序，您可以在其中保存学生的姓名，图片和角色。一切正常，但我的代码不会在我的核心数据模型中保存图像。我一整天都想弄明白。

您可以在此处找到我的整个项目：http://www21.zippyshare.com/v/26184330/file.html

#import "AddStudent.h"
#import "Studenten.h"
#import "Bild.h"
#import <QuartzCore/QuartzCore.h>

@interface AddStudent () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>
@end

@implementation AddStudent;
@synthesize delegate;
@synthesize managedObjectContext = _managedObjectContext;
@synthesize selectedBetreuungsgrund;
@synthesize studentBetrGrundCell = _studentBetrGrundCell;
@synthesize vorschauImageView = _vorschauImageView;

- (void)viewWillAppear:(BOOL)animated {

    _studentBetrGrundCell.textLabel.text = @"";
    _studentBetrGrundCell.delegate = self;
    _studentBetrGrundCell.managedObjectContext = self.managedObjectContext;
}
- (void)betrGrundWasSelectedOnPicker:(Betreuungsgrund *)betreuungsgrund {

    self.selectedBetreuungsgrund = betreuungsgrund;
    _studentBetrGrundCell.textLabel.text = self.selectedBetreuungsgrund.name;
}

- (void)viewDidUnload
{
    [super viewDidUnload];
}

- (void)dismissKeyboard {
    [self.view endEditing:TRUE];
}

- (void)viewDidLoad {
    [super viewDidLoad];

    self.studentNachnameTextfeld.delegate = self;
    self.studentVornameTextFeld.delegate = self;
    _studentNachnameTextfeld.autocapitalizationType = UITextAutocapitalizationTypeSentences;
    _studentVornameTextFeld.autocapitalizationType = UITextAutocapitalizationTypeSentences;
    UITapGestureRecognizer *tgr = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissKeyboard)];
    [tgr setCancelsTouchesInView:NO];
    [self.tableView addGestureRecognizer:tgr];
}


- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    [textField resignFirstResponder];
    return YES;
}

- (IBAction)save:(id)sender

{

        if (([_studentNachnameTextfeld.text isEqualToString:(@"")])||([_studentVornameTextFeld.text isEqualToString:(@"")])){
            UIAlertView *alert = [[UIAlertView alloc]initWithTitle:nil message:@"Sie müssen alle Namensfelder ausfüllen!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
            [alert show];
        }
        else {

        Student *student = [NSEntityDescription insertNewObjectForEntityForName:@"Student"
                                                             inManagedObjectContext:self.managedObjectContext];

        student.vorname = _studentVornameTextFeld.text;
        student.name = _studentNachnameTextfeld.text;
        student.hatBetrGrund = selectedBetreuungsgrund;        //Funzt trotzdem

        student.bild.vorschauData = _vorschauImageView.image;
         NSLog(@"Image Core Data: %@", _vorschauImageView.image);
         NSLog(@"Image Core Data DB: %@", student.bild.vorschauData);
         // NSLog(@"Betreuungsgrund: %@", student.hatBetrGrund);

        [self.managedObjectContext save:nil];  // Eintrag in Datenbank
        [self.delegate AddStudentSavePressed:self];
        NSLog (@"Save Button bei AddBetrGrund pressed");            
        }
}

- (IBAction)albumButtonPressed:(id)sender
{
    if (! [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary] ) {
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Error" message:@"Es steht kein Album zur Verfügung!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
        [alert show];
        return;
    }
    UIImagePickerController *controller = [[UIImagePickerController alloc] init];
    controller.delegate = self;
    controller.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    [self presentViewController:controller animated:YES completion:nil];
}

- (IBAction)kameraButtonPressed:(id)sender
{
    if (! [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] ) {
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Error" message:@"Es steht keine Kamera zur Verfügung!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
        [alert show];
        return;
    }
    UIImagePickerController *controller = [[UIImagePickerController alloc] init];
    controller.delegate = self;
    controller.sourceType = UIImagePickerControllerSourceTypeCamera;
    [self presentViewController:controller animated:YES completion:nil];
}

- (IBAction)deleteBildPressed:(id)sender {
    self.vorschauImageView.image = nil;
}

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo 
{
    [picker dismissViewControllerAnimated:YES completion:nil];
    _vorschauImageView.image = image;
    _vorschauImageView.layer.cornerRadius = 10; // abgerundete Ecken
    NSLog(@"Image Vorschau: %@", _vorschauImageView.image);
}

提前感谢您的帮助。干杯

Answer 1

通常，您不应将图像保存在Core Data中。而是将其保存在磁盘上的文件中，并将路径保存到Core Data模型中的文件中。

这一行：

student.bild.vorschauData = _vorschauImageView.image;

使student看起来像是与包含图像的其他对象有关系（bild）。您需要创建该对象，将其插入上下文并将其与student关联，然后才能使用它。

无法在Core Data中保存图像

1 个答案: