ios - 如何在单击三层时设置 UIBarButtonItem 图像

Question

您好，我当前的代码如下，我想知道如何在当前的 if 语句中实现按钮图标更改(如果可能)，如果不可能，那么我需要使用什么代码？非常感谢。

viewController.m

   #import "GroupsViewController.h"
    #import "CustomCell.h"

    @interface GroupsViewController ()
    {
        NSArray *arrayOfImages;
        NSArray *arrayOfDescriptions;
    }

    @end

    @implementation GroupsViewController
    {
        NSString *reuseIdentifier;
    }

    - (void)viewDidLoad
    {
        [super viewDidLoad];
        [[self GroupsCollectionView]setDataSource:self];
        [[self GroupsCollectionView]setDelegate:self];
        reuseIdentifier= @"SmallIcon";

        arrayOfImages = [[NSArray alloc]initWithObjects:@"?.png", nil];

        arrayOfDescriptions = [[NSArray alloc]initWithObjects:@"?", nil];

    }

    -(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
    {
        return 1;
    }

    -(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
    {
        return [arrayOfDescriptions count];
    }

    -(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
    {

        CustomCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];

        [[cell IconImage]setImage:[UIImage imageNamed:[arrayOfImages objectAtIndex:indexPath.item]]];
        [[cell IconLabel]setText:[arrayOfDescriptions objectAtIndex:indexPath.item]];

        return cell;
    }

    - (void)didReceiveMemoryWarning
    {
        [super didReceiveMemoryWarning];
        //Dispose of any resources that can be recreated.
    }

- (IBAction)cellToggleAction:(id)sender {

    if([reuseIdentifier isEqualToString:@"SmallIcon"]){
        reuseIdentifier=@"ListView";
        [sender setImage:[UIImage imageNamed:@"scion.png"] forState:UIControlStateNormal];
    }
    else if
        ([reuseIdentifier isEqualToString:@"ListView"]){
        reuseIdentifier=@"LargeIcon";
        [sender setImage:[UIImage imageNamed:@"subaru.png"] forState:UIControlStateNormal];
    }
    else if
        ([reuseIdentifier isEqualToString:@"LargeIcon"]){
        reuseIdentifier=@"SmallIcon";
        [sender setImage:[UIImage imageNamed:@"lotus.png"] forState:UIControlStateNormal];
    }

    [self.GroupsCollectionView reloadData];
}

    - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {

        CGSize cellSize;

        if([reuseIdentifier isEqualToString:@"SmallIcon"])
            cellSize = CGSizeMake(100, 130);
        else if
            ([reuseIdentifier isEqualToString:@"ListView"])
            cellSize = CGSizeMake(320, 130);
        else if
            ([reuseIdentifier isEqualToString:@"LargeIcon"])
            cellSize = CGSizeMake(320, 350);

        return cellSize;
    }
    @end

在实现您当前的建议后，我收到以下错误消息:

[UIBarButtonItem setImage:forState:]: unrecognized selector sent to instance

Answer 1

编辑:结果是 sender 是 UIBarButtonItem 的一个实例

对于此类，使用方法 setBackgroundImage:forState:barMetrics:代替setImage:forState:就像下面的原始帖子一样，它是针对 UIButton 的。同时将 sender 类型转换为 UIBarButtonItem

[(UIBarButtonItem*)sender setBackgroundImage:[UIImage imageNamed:@"scion.png"] forState:UIControlStateNormal barMetrics: UIBarMetricsDefault];

原帖:假设 (id)sender 是您要在名为-cellToggleAction:(id)sender 的方法中更改的UIButton 实例, 将 sender 类型转换为 UIButton 然后调用 -setImage:forState:在 if 语句中。

或者，您可以将上述方法更改为具有类型为 UIButton 而不是 id 的参数，以避免类型转换，这也使代码更具可读性.

一个例子可能是-

- (IBAction)cellToggleAction:(UIButton*)sender {

if([reuseIdentifier isEqualToString:@"SmallIcon"]) {
    reuseIdentifier=@"ListView";
    [sender setImage:yourImage forState:UIControlStateNormal];// may need other states configured
}
else if .. // continue similarly