在uinavigationbar中添加带有两个uibarbuttonitem的uitoolbar:poor uitoolbar和iphone 4怎么样?

我在听第二条建议 here . 在这个技巧中,两个uibarbuttonitim放在一个uitoolbar中。最后,将uitoolbar添加到uinavigationbar。现在我的问题是:

1)U工具栏顶部有一条白线。如果我增加uitoolbar的大小,那么梯度就错了。我正在使用以下尺寸的Uitoolbar:

    UIToolbar *toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 90, 44.01)];

我怎样才能去掉白线?请参见此处:

问题是有一条白色而不是灰色的线。如果是灰色的,一切都会很完美。

2)iPhone3和iPhone4的显示尺寸有什么不同?我需要检查使用的是哪一款iPhone,然后再加倍吗?

编辑:

按钮的创建方式与我从上述网站上获取的以下示例类似:

// create a toolbar to have two buttons in the right
UIToolbar* tools = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 133, 44.01)];

// create the array to hold the buttons, which then gets added to the toolbar
NSMutableArray* buttons = [[NSMutableArray alloc] initWithCapacity:3];

// create a standard "add" button
UIBarButtonItem* bi = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:NULL];
bi.style = UIBarButtonItemStyleBordered;
[buttons addObject:bi];
[bi release];

// create a spacer
bi = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
[buttons addObject:bi];
[bi release];

// create a standard "refresh" button
bi = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh:)];
bi.style = UIBarButtonItemStyleBordered;
[buttons addObject:bi];
[bi release];

// stick the buttons in the toolbar
[tools setItems:buttons animated:NO];

[buttons release];

// and put the toolbar in the nav bar
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:tools];
[tools release];

@锝:

我试着将其分类 UIToolbar .

// MyToolbar.h

#import <Foundation/Foundation.h>


@interface MyToolbar : UIToolbar {

}

@end

// MyToolbar.m

#import "MyToolbar.h"


@implementation MyToolbar

- (void)drawRect:(CGRect)rect {
    // do nothing
}

- (id)initWithFrame:(CGRect)aRect {
    if ((self = [super initWithFrame:aRect])) {
        self.opaque = NO;
        self.backgroundColor = [UIColor clearColor];
        self.clearsContextBeforeDrawing = YES;      
    }
    return self;
}

@end