两个警告 - （NSInteger）tableView：（UITableView *）tableView indentationLevelForRowAtIndexPath：（NSIndexPath *）indexPath方法

Question

我已经注意到了这个方法的两个警告。

我该如何解决这个问题？代码如下。

提前致谢。

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController
@synthesize listData;

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    NSArray *array = [[NSArray alloc] initWithObjects:@"Sleepy", @"Sneezy", @"Bashful", @"Happy", @"Doc", @"Grumpy", @"Dopey", @"Thorin", @"Dorin", @"Nori", @"Ori", @"Balin", @"Dwalin", @"Fili", @"Kili", @"Oin", @"Gloin", @"Bifur", @"Bofur", @"Bombur", nil];
    self.listData = array;
}

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

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

#pragma mark -
#pragma mark Table View Data Source Methods
- (NSInteger)tableView:(UITableView *)tableView
    numberOfRowsInSection:(NSInteger)section
{
    return [self.listData count];
}

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

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

    UIImage *image = [UIImage imageNamed:@"star.png"];
    cell.imageView.image = image;

    NSUInteger row = [indexPath row];
    cell.textLabel.text = [listData objectAtIndex:row];


    if (row < 7)
        cell.detailTextLabel.text = @"Mr. Disney";
    else
        cell.detailTextLabel.text = @"Mr.Tolkien";

     return cell;
}

#pragma mark -
#pragma mark Table Delegate Methods

- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSUInteger row = [indexPath row];

    if (row == 0)
    return nil; /* Incompatible pointer to integer conversion returning ‘void *' from a function with result type 'NSInteger' (aka 'int').*/

    return indexPath; /* Incompatible pointer to integer conversion returning ‘NSIndexPath*_strong' from a function with result type 'NSInteger' (aka 'int').*/
}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSUInteger row = [indexPath row];
    NSString *rowValue = [listData objectAtIndex:row];

    NSString *message = [[NSString alloc] 
                         initWithFormat:@"You selected %@", rowValue];
    UIAlertView *alert = [[UIAlertView alloc]
                          initWithTitle:@"Row selected" 
                          message:message 
                          delegate:nil 
                          cancelButtonTitle:@"Yes I Did" 
                          otherButtonTitles: nil];
    [alert show];
}



@end

Answer 1

该函数指定它将返回一个NSInteger，返回nil或NSIndexPath将破坏该promise。怎么样：

NSInteger row = (NSInteger)[IndexPath row]; //casts the NSUInteger to NSInteger

if (row == 0)
{
    return 0;
}  

return row;