UIButton作为UINavigationbar按钮

Question

我有一个Tab栏应用程序.在其中一个标签栏中,我有一个导航控制器.我试图设置一个UIButton与图像作为导航栏的右键.

    UIButton *refreshButton = [[UIButton alloc] init];
    [refreshButton setImage:[UIImage imageNamed:@"refresh_icon.png"] forState:UIControlStateNormal];
    [refreshButton addTarget:self action:@selector(refreshSection) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithCustomView:refreshButton];
    //[rightButton setImage:[UIImage imageNamed:@"refresh_icon.png"]]; << DOESN'T WORK EITHER  
    self.navigationItem.rightBarButtonItem = rightButton;
    [refreshButton release];
    [rightButton release];

但图像没有显示出来.我得到一个隐形按钮.

编辑: 我希望按钮样​​式为普通或背景为透明,以便只显示图像.因此我使用UI按钮而不是直接使用UIBarButton.

Answer 1

您不必创建UIButton并将其用作自定义视图UIBarButtonItem.您可以UIBarButtonItem直接使用图片创建:

UIImage *myImage = [UIImage imageNamed:@"myImage.png"];
UIBarButtonItem *button = [[UIBarButtonItem alloc] initWithImage:myImage style:UIBarButtonItemStyleBordered target:self action:@selector(refreshSection)];  
self.navigationItem.rightBarButtonItem = button;    
[button release];

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根据评论更新

在以下位置使用UIImageView自定义视图UIBarButtonItem:

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"myImage.png"]];
UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithCustomView:imageView];
self.navigationItem.rightBarButtonItem = rightButton;
[imageView release];
[rightButton release];

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更新

尝试了最后一种方法,虽然这看起来像你想要它,我似乎无法让它来处理水龙头.虽然目标和行动已经确定.

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最后更新

我已经在问题中运行了初始代码.图像未显示的原因是因为您尚未设置按钮的框架.设置框架后,图像将显示在导航栏中.

这是我使用和测试过的片段:

UIImage *myImage = [UIImage imageNamed:@"paw.png"];
UIButton *myButton = [UIButton buttonWithType:UIButtonTypeCustom];
[myButton setImage:myImage forState:UIControlStateNormal];
myButton.showsTouchWhenHighlighted = YES;
myButton.frame = CGRectMake(0.0, 0.0, myImage.size.width, myImage.size.height);

[myButton addTarget:self action:@selector(tapped:) forControlEvents:UIControlEventTouchUpInside];

UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithCustomView:myButton];
self.navigationItem.rightBarButtonItem = rightButton;

[rightButton release];
[myButton release];

注意:按下按钮时,我已设置了按钮的视觉高亮显示showsTouchWhenHighlighted属性UIButton.