为 UIToolbar 添加图像到 UIBarButtonItem

Question

我正在尝试向 UIBarButtonItem 添加图像，我必须在 UIToolbar 中使用它。

我已经设法读取图像，甚至让它与 UIImageView 一起显示，但是当我将它添加到 UIBarButtonItem 然后将该项目添加到 UIToolbar 时，工具栏只会取代“空白”空间的大小和我正在尝试加载的图像的形状。

这是我正在尝试的。

UIImage *image = [UIImage imageNamed:@"6.png"];

//This is the UIImageView that I was using to display the image so that i know that it is being read from the path specified.  
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
imageView.frame = CGRectMake(0, 50, image.size.width, image.size.height);
[self.view addSubview:imageView];

UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
[button1 setImage:image forState:UIControlStateNormal];

//This is the first way that I was trying to accomplish the task but i just get a blank white space

//This is the Second way but with the same blank white result.
UIBarButtonItem *systemItem1 = [[UIBarButtonItem alloc] initWithCustomView:button2];

NSArray *items = [NSArray arrayWithObjects: systemItem1, nil];

//Adding array of buttons to toolbar
[toolBar setItems:items animated:NO];

//Adding the Toolbar to the view.
[self.view addSubview:toolBar];

您的帮助将不胜感激。

谢谢！

Shumais Ul Haq

Answer 1

除了您通常在 UIKit 中所期望的之外，您可能需要明确地为按钮设置一个框架。也许这就是你的问题。

这是我为自定义样式的后退按钮编写的，作为UIBarButtonItem 的一个类别（但您可以从中获取所需的部分）。

请注意，这用于导航栏，而不是工具栏，但我认为机制是相同的，因为它也是 UIBarButtonItem。对于UIToolbar，您只需在编译时使用 IB 即可。

#define TEXT_MARGIN 8.0f
#define ARROW_MARGIN 12.0f
#define FONT_SIZE 13.0f
#define IMAGE_HEIGHT 31.0f

+(UIBarButtonItem*)arrowLeftWithText:(NSString*)txt target:(id)target action:(SEL)selector
{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    UIImage *img = [[UIImage imageNamed:@"arrow_left.png"]
        stretchableImageWithLeftCapWidth:15 topCapHeight:0];

    [btn addTarget:target action:selector forControlEvents:UIControlEventTouchDown];

    [btn setContentHorizontalAlignment:UIControlContentHorizontalAlignmentRight];
    [btn setContentEdgeInsets:UIEdgeInsetsMake(0.0f,0.0f,0.0f,TEXT_MARGIN)];
    [btn.titleLabel setFont:[UIFont fontWithName:@"Helvetica-Bold" size:FONT_SIZE]];
    [btn.titleLabel setShadowOffset:CGSizeMake(0.0f,-1.0f)];

    /**** this is the magic line ****/
    btn.frame = CGRectMake(0.0f,0.0f,
        [txt sizeWithFont:[btn.titleLabel font]].width+ARROW_MARGIN+TEXT_MARGIN,
        IMAGE_HEIGHT);

    [btn styleBarButtonForState:UIControlStateNormal withImage:img andText:txt];
    [btn styleBarButtonForState:UIControlStateDisabled withImage:img andText:txt];
    [btn styleBarButtonForState:UIControlStateHighlighted withImage:img andText:txt];
    [btn styleBarButtonForState:UIControlStateSelected withImage:img andText:txt];
    return [[[UIBarButtonItem alloc] initWithCustomView:btn] autorelease];
}

用法：

[UIBarButtonItem arrowLeftWithText:@"Back" target:self action:@selector(dismiss)];