在 TableView 中按“编辑”按钮时无法启动 self.editing 模式

Question

我正在尝试在 iPhone 应用程序中创建一个可编辑的表格。我有两个问题。

1. 当我按下“编辑”按钮并进入编辑模式时，我无法删除一行。

2. 是否有一种方法可以添加“添加新单元格”功能，而不是像我在代码中那样？ （我添加了一个 addButtonAction 方法。）

这是我的 .h

#import <UIKit/UIKit.h>

@interface FirstViewController : UITableViewController <UITableViewDelegate, UITableViewDataSource>
{
    UITableView *table;
    NSMutableArray *tableDataSource;
}

-(IBAction)addButtonAction:(id)sender;

@end

这是 .m

#import "FirstViewController.h"

@implementation FirstViewController

- (IBAction)addButtonAction:(id)sender
{
    if(tableDataSource != nil)
    {
        [tableDataSource addObject:@"New City"];
    }
    [table reloadData];
}

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    tableDataSource = [[NSMutableArray alloc]init];
    [tableDataSource addObjectsFromArray:[NSArray arrayWithObjects: @"Canada", @"United States", @"Australia", @"United Kingdom", nil]];

    table = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, 320, 367) style:UITableViewStyleGrouped];
    [table setDataSource:self];
    [table setDelegate:self];
    [self.view addSubview:table];

    [[self navigationItem] setLeftBarButtonItem:[self editButtonItem]];

    UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
                              target:self
                              action:@selector(addButtonAction:)];
    [[self navigationItem] setRightBarButtonItem:addButton];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    [[self tableView] reloadData];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [tableDataSource count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    // Configure the cell...
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    cell.textLabel.text = [tableDataSource objectAtIndex:indexPath.row];

    return cell;
}

#pragma - Enable/Disable Edit Button

- (void)setEditing:(BOOL)editing animated:(BOOL)animated
{
    [super setEditing:editing
             animated:animated];

    [table setEditing:editing animated:animated];
}

#pragma - Editing Style

// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
   return YES;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) 
    {
        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
    }   
    else if (editingStyle == UITableViewCellEditingStyleInsert) 
    {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }   
}

#pragma - Can Move Row

// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
    NSString *item = [tableDataSource objectAtIndex:fromIndexPath.row];
    [tableDataSource removeObject:item];
    [tableDataSource insertObject:item atIndex:toIndexPath.row];
}

// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

#pragma mark - Table Title

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    if(section == 0)
    {
        return @"City";
    }

    else 
    {
        return @"Nothing here";
    }
}

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.section == 0)
    {
        //TBD....
    }

    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

@end

Answer 1

1. 确保从 tableView 中删除行时也从 NSArray 中删除该对象。

2. 我认为这个 addButton 可以工作，但是这个

   如果（单元格==零）{
   cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefaultreuseIdentifier:CellIdentifier];
   我认为

这样：

cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefaultreuseIdentifier:CellIdentifier];

只需删除 if 语句...
希望我理解你的问题并提供帮助。