UINavigatiobar 右栏按钮项目图像不可见

Question

我正在为 UINavigation 栏创建自定义右栏按钮项。这是我正在使用的代码，

UIView *container = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 40)];
    UIButton *backPageButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [backPageButton setFrame:CGRectMake(0, 0, 50, 30)];
    [ backPageButton setImage:[UIImage imageNamed:@"left_arrow.png"] forState:UIControlStateNormal];
    backPageButton.imageView.contentMode = UIViewContentModeScaleAspectFill;
    [backPageButton addTarget:self action:@selector(backButtonAction) forControlEvents:UIControlEventTouchUpInside];
    [backPageButton setUserInteractionEnabled:YES];
    [container addSubview:backPageButton];
    UIButton *forwardPageButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [forwardPageButton setFrame:CGRectMake(30, 0, 50, 30)];
    [ forwardPageButton setImage:[UIImage imageNamed:@"right_arrow.png"] forState:UIControlStateNormal];
    [forwardPageButton addTarget:self action:@selector(forwardButtonAction) forControlEvents:UIControlEventTouchUpInside];
    forwardPageButton.imageView.contentMode = UIViewContentModeScaleAspectFill;
    [forwardPageButton setUserInteractionEnabled:YES];
    [container addSubview:forwardPageButton];

    UIBarButtonItem* item = [[UIBarButtonItem alloc] initWithCustomView:container];

// set the nav bar's right button item
self.navigationItem.rightBarButtonItem = item;

由于某种原因，按钮图像不可见。我为每个按钮添加了背景颜色，可以看到按钮实际上已添加到导航栏，并且单击事件也正常工作。但按钮图像不可见。

如何解决？

谢谢

Answer 1

1. 您当然已经仔细检查了图像是否属于您的目标？
2. 要在运行时调试视图，您可以在 Xcode 中使用小但非常有用的按钮

更多信息：https://developer.apple.com/library/ios/recipes/xcode_help-debugger/using_view_debugger/using_view_debugger.html