@ T-X解决了这个问题。我在代码中用“// SOLUTION”标记了这些更改!!!
我有以下问题,如果我使用了MostModalViewController,则NSMutableArray“projectsArray”会被重置。
这是我的代码:
这里是.h文件:
// ViewController.h
#import <UIKit/UIKit.h>
@class AddProject;
@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
{
IBOutlet UITableView *projectsTableView;
UIAlertView *reallyDelete;
BOOL candelButtonClicked;
NSIndexPath *actualIndexPath;
NSMutableArray *projectsArray;
NSInteger ID;
NSString *NAME;
AddProject *addProject;
**ViewController *viewContr; // SOLUTION**
}
- (IBAction)addNewProject:(id)sender;
- (void)addToTableView:(NSString *)projectName;
@property (nonatomic, retain) UIAlertView *reallyDelete;
@property (nonatomic) NSInteger cancelButtonIndex;
@property IBOutlet UITableView *projectsTableView;
@property (nonatomic, retain) AddProject *addProject;
**@property (nonatomic, retain) ViewController *viewContr; // SOLUTION**
@end
这里是.m文件:
// ViewController.m
#import "ViewController.h"
#import "CustomTableCell.h"
#import "AddProject.h"
@interface ViewController ()
@end
@implementation ViewController
**@synthesize viewContr; // SOLUTION**
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
projectsArray = [[NSMutableArray alloc] init];
ViewController *element = [[ViewController alloc] init];
element->ID = 1;
element->NAME = @"Demo project";
NSLog(@"viewdidload");
[projectsArray addObject:element];
NSLog(@"1. Array length: %d", [projectsArray count]);
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if ([projectsArray count] < 1) {
NSLog(@"2. Array length: 0");
return 0;
} else {
NSLog(@"2. Array length: %d", [projectsArray count]);
return [projectsArray count];
}
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 78;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *customTableCellIdentifier = @"CustomTableCell";
CustomTableCell *cell = (CustomTableCell *)[tableView dequeueReusableCellWithIdentifier:customTableCellIdentifier];
if (cell == nil)
{
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomTableCell" owner:self options:nil];
cell = [nib objectAtIndex:0];
}
ViewController *element = [[ViewController alloc] init];
element = [projectsArray objectAtIndex:indexPath.row];
cell.nameLabel.text = element->NAME;
cell.prepTimeLabel.text = [NSString stringWithFormat:@"%i", element->ID];
NSLog(@"3. Array length: %d", [projectsArray count]);
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
reallyDelete = [[UIAlertView alloc] initWithTitle:@"Deleting" message:@"Do your really want to delete that row?" delegate:self cancelButtonTitle:@"No" otherButtonTitles:@"Yes", nil];
[reallyDelete show];
actualIndexPath = indexPath;
}
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex != [reallyDelete cancelButtonIndex])
{
//If "Yes" clicked delete
[projectsArray removeObjectAtIndex:actualIndexPath.row];
NSLog(@"delete row");
[self.projectsTableView deleteRowsAtIndexPaths:[NSMutableArray arrayWithObjects:actualIndexPath, nil] withRowAnimation:YES];
[self.projectsTableView reloadData];
}
}
#pragma mark Edit
- (IBAction)addNewProject:(id)sender {
NSLog(@"4. Array length: %d", [projectsArray count]);
AddProject *addProjectView = [[AddProject alloc] initWithNibName:@"AddProject" bundle:nil];
NSLog(@"4.1 Array length: %d", [projectsArray count]);
addProjectView.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
NSLog(@"4.2 Array length: %d", [projectsArray count]);
addProjectView.modalPresentationStyle = UIModalPresentationFormSheet;
NSLog(@"4.3 Array length: %d", [projectsArray count]);
**addProjectView.viewContr = self; // SOLUTION**
[self presentModalViewController:addProjectView animated:YES];
NSLog(@"4.4 Array length: %d", [projectsArray count]);
addProjectView.view.superview.frame = CGRectMake(addProjectView.view.center.x/2.5, addProjectView.view.center.y/3, 800, 600);
NSLog(@"4.5 Array length: %d", [projectsArray count]);
}
- (void)addToTableView:(NSString *)projectName
{
NSLog(@"Project Array: %@", projectsArray);
NSLog(@"addToTableView: %@", projectName);
NSLog(@"5. Array length: %d", [projectsArray count]);
ViewController *element = [[ViewController alloc] init];
element->ID = 2;
element->NAME = projectName;
[projectsArray addObject:element];
NSLog(@"6. Array length: %d", [projectsArray count]);
[self.projectsTableView reloadData];
[self.projectsTableView setNeedsDisplay];
}
- (void)viewDidUnload
{
[self setProjectsTableView:nil];
self.projectsTableView = nil;
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
@end
这里是模态呈现视图的.h文件:
// AddProject.h
#import <UIKit/UIKit.h>
@class ViewController;
@interface AddProject : UIViewController
{
IBOutlet UITextField *projectName;
ViewController *viewContr;
}
- (IBAction)back:(id)sender;
- (IBAction)next:(id)sender;
@property (nonatomic, retain) ViewController *viewContr;
@end
模态呈现文件的.m文件:
// AddProject.m
#import "AddProject.h"
#import "ViewController.h"
@interface AddProject ()
@end
@implementation AddProject
**@synthesize viewContr; // SOLUTION I've mist to synthesize it**
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
**// SOLUTION no new allocation/init of ViewController**
}
- (IBAction)back:(id)sender
{
[self dismissModalViewControllerAnimated:YES];
}
- (IBAction)next:(id)sender
{
[viewContr addToTableView:projectName.text];
[viewContr.projectsTableView reloadData];
[viewContr.projectsTableView setNeedsDisplay];
[self dismissModalViewControllerAnimated:YES];
}
- (void)viewDidUnload
{
projectName = nil;
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
@end
我已经使用断点测试了代码,我可以在AddProject类“viewDidLoad”开始加载时找到问题。但我不知道为什么它会重置数组。
答案 0 :(得分:1)
您应该在视图控制器的init方法中分配projectsArray,而不是在viewDidLoad中。 projectsArray = [[NSMutableArray alloc] init];
在加载视图时分配了一个新的空数组。
答案 1 :(得分:1)
您从ViewController
屏幕导航到Add project
屏幕。在Add Project
屏幕中,您添加了一个新项目,并希望将此信息委托给您来自的ViewController
屏幕。
现在,您正试图在ViewController
中创建一个AddProject
的实例,您在viewDidLoad
方法中新实例化,并且在添加项目时,您通过以下方式提供信息:在其上调用- (void)addToTableView:(NSString *)projectName
。
这不起作用,因为 - 您分配的ViewController
实例是一个新实例,而不是您导航的实例。当你alloc + init
时,你得到一个新对象。因此,尽管您在addToTableView:
上调用ViewController
,但它不起作用,因为接收此消息的ViewController
实例是新实例,而不是您导航的实例。< / p>
因此,您需要做的就是 - ViewController
中有一个Add Project
属性,您可以在导航之前设置该属性。然后您可以向此属性发送消息 - 如this成绩单中所述。
我想说 - 但是这件事有效,它提供了两个控制器之间的紧密耦合。
理想情况下,可以通过将ViewController
(您从哪里导航)作为Add Project
(您导航到的地方)的代表来完成此操作。然后Add Project
可以通过类似- (void) addProjectController:(AddProjectViewController *) controller didAddProject:(NSString *) projectName
的方式将添加的项目委托给它的委托。这提供了两个视图控制器之间的耦合丢失。要了解委派概念,请参阅Delegates and Datasources。或者,搜索其他堆栈溢出帖子。
答案 2 :(得分:0)
好的,我的问题是通过stackoverflow聊天修复的。最终解决方案的提示来自用户@ T-X。我在我的问题中添加了代码中的提示。它们标有“// SOLUTION”。
在“添加项目视图”控制器的viewDidLoad方法中,删除该行
viewContr = [[ViewController alloc] init];
。现在制作变量viewContr
类ViewController
中的一个属性。也合成 它。最后在- (IBAction)addNewProject:(id)sender
方法中, 在呈现控制器之前,执行- addProjectView.viewContr = self;
。它将解决您的问题。
(引自chat.stackoverflow | @T-X)