更改 UIBarButtonItem 的图像时遇到问题

Question

我正在尝试各种方法来更改 UIBarButtonItem 的图像，一旦按下它，但没有任何运气。

// bookmarkButton is a property linked up in IB
-(IBAction)bookmarkButtonTapped:(id)sender
{
NSLog(@"this action triggers");
// attempt 1
UIBarButtonItem* aBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"bookmarkdelete.png"] style:UIBarButtonItemStylePlain target:self action:@selector(bookmarkButtonTapped:)];
bookmarkButton = aBarButtonItem;
[aBarButtonItem release];

// attempt 2
bookmarkButton.image = [UIImage imageNamed:@"bookmarkdelete.png"];
}

还有其他方法可以做到这一点吗？

Answer 1

工具栏包含一个数组 - items - 作为属性。因此，将工具栏设置为 IBOutlet 属性后，我必须在该数组中插入一个新按钮。如下所示：

NSMutableArray *items = [[NSMutableArray alloc] initWithArray:self.toolBar.items];
UIBarButtonItem *newButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"newButton.png"]  style:UIBarButtonItemStylePlain target:self action:@selector(buttonTapped:)];
[items replaceObjectAtIndex:0 withObject:newButton];
self.toolBar.items = items;
[newButton release];
[items release];

Answer 2

bookmarkButton 是 UIButton 吗？是否应该通过 (UIButton *)aBarButtonItem.customView 引用而不是直接引用？

如果它是 UIButton，那么您需要根据状态设置图像： - (void)setImage:(UIImage *)image forState:(UIControlState)state

请注意，还有一个 >setBackgroundImage 使用相同的 API（如果您需要的话）。

Answer 3

这应该有效

UIImage *normalButtonImage = [UIImage imageNamed:@"TableViewIcon"];
UIImage *selectedButtonImage = [UIImage imageNamed:@"CollectionViewIcon"];
CGRect rightButtonFrame = CGRectMake(0, 0, normalButtonImage.size.width,
                                     normalButtonImage.size.height);
UIButton *rightButton = [[UIButton alloc] initWithFrame:rightButtonFrame];
[rightButton setBackgroundImage:normalButtonImage forState:UIControlStateNormal];
[rightButton setBackgroundImage:selectedButtonImage forState:UIControlStateSelected];
[rightButton addTarget:self action:@selector(toggleTableView:)
      forControlEvents:UIControlEventTouchDown];
self.toggleMediaView = [[UIBarButtonItem alloc] initWithCustomView:rightButton];
[self.navigationItem setLeftBarButtonItem:self.toggleMediaView];
self.navigationItem.leftBarButtonItem.enabled = NO;

Answer 4

尝试 [bookmarkButton setImage:[UIImage imageNamed:@"bookmarkdelete.png"] forState:UIControlStateNormal];