ios - iPad 撤消按钮(a-la Keynote 和其他应用程序)

Question

在 Keynote(和其他应用程序)中，我注意到执行撤消/重做的“标准”界面是在工具栏上提供撤消按钮。

单击按钮(始终启用)撤消最近的操作。(如果没有最近的操作要撤销，它会显示撤销/重做菜单)。

长按撤消按钮打开撤消/重做菜单。

我搜索了实现它的方法，目前我找到的最佳答案是 following link .

不知有没有人知道更简单的方法？

谢谢!

Answer 1

在查看所有方法并与 friend 讨论后，下面是我使用的解决方案，对于 UIBarButtonItem，它响应点击和长按 (TapOrLongPressBarButtonItem)。

它基于以下原则:

1. 子类 UIBarButtonItem
2. 使用自定义 View (因此处理长按真的很简单 - 因为我们的自定义 View 可以毫无问题地响应长按手势处理程序...)

... 到目前为止 - 这种方法在 other SO thread 中- 我不喜欢这种方法，因为我找不到足够简单的方法来使自定义 View 看起来像 iPad 导航栏按钮......太棒了......

使用 UIGlossyButton作者 Water Lou(感谢水!)。这种使用被封装在子类中...

结果代码如下:

@protocol TapOrPressButtonDelegate;
@interface TapOrPressBarButtonItem : UIBarButtonItem {  
    UIGlossyButton* _tapOrPressButton;
    __weak id<TapOrPressButtonDelegate> _delegate;
}
- (id)initWithTitle:(NSString*)title andDelegate:(id<TapOrPressButtonDelegate>)delegate;
@end

@protocol TapOrPressButtonDelegate<NSObject>
- (void)buttonTapped:(UIButton*)button withBarButtonItem:(UIBarButtonItem*)barButtonItem;
- (void)buttonLongPressed:(UIButton*)button withBarButtonItem:(UIBarButtonItem*)barButtonItem;
@end

@implementation TapOrPressBarButtonItem
- (void)buttonLongPressed:(UILongPressGestureRecognizer*)gesture {
    if (gesture.state != UIGestureRecognizerStateBegan)
        return;
    if([_delegate respondsToSelector:@selector(buttonLongPressed:withBarButtonItem:)]) {
        [_delegate buttonLongPressed:_tapOrPressButton withBarButtonItem:self];
    }
}

- (void)buttonTapped:(id)sender {
    if (sender != _tapOrPressButton) {
        return;
    }

    if([_delegate respondsToSelector:@selector(buttonTapped:withBarButtonItem:)]) {
        [_delegate buttonTapped:_tapOrPressButton withBarButtonItem:self];
    }   
}

- (id)initWithTitle:(NSString*)title andDelegate:(id<TapOrPressButtonDelegate>)delegate {
    if (self = [super init]) {
        // Store delegate reference
        _delegate = delegate;

        // Create the customm button that will have the iPad-nav-bar-default appearance 
        _tapOrPressButton = [UIGlossyButton buttonWithType:UIButtonTypeCustom];
        [_tapOrPressButton setTitle:title forState:UIControlStateNormal];
        [_tapOrPressButton setNavigationButtonWithColor:[UIColor colorWithRed:123.0/255 green:130.0/255 blue:139.0/255 alpha:1.0]];
        // Calculate width...
        CGSize labelSize = CGSizeMake(1000, 30);
        labelSize = [title sizeWithFont:_tapOrPressButton.titleLabel.font constrainedToSize:labelSize lineBreakMode:UILineBreakModeMiddleTruncation];
        _tapOrPressButton.frame = CGRectMake(0, 0, labelSize.width+20, 30);

        // Add a handler for a tap
        [_tapOrPressButton addTarget:self action:@selector(buttonTapped:) forControlEvents:UIControlEventTouchUpInside];
        // Add a handler for a long-press
        UILongPressGestureRecognizer* buttonLongPress_ = [[UILongPressGestureRecognizer alloc] initWithTarget:self
                                                                                                       action:@selector(buttonLongPressed:)];
        [_tapOrPressButton addGestureRecognizer:buttonLongPress_];

        // Set this button as the custom view of the bar item...
        self.customView = _tapOrPressButton;
    }
    return self;
}

// Safe guards...
- (id)initWithImage:(UIImage *)image style:(UIBarButtonItemStyle)style target:(id)target action:(SEL)action {
    NSLog(@"%s not supported!", __FUNCTION__);
    return nil;
}

- (id)initWithImage:(UIImage *)image landscapeImagePhone:(UIImage *)landscapeImagePhone style:(UIBarButtonItemStyle)style target:(id)target action:(SEL)action {
    NSLog(@"%s not supported!", __FUNCTION__);
    return nil;
}

- (id)initWithTitle:(NSString *)title style:(UIBarButtonItemStyle)style target:(id)target action:(SEL)action {
    NSLog(@"%s not supported!", __FUNCTION__);
    return nil;
}
- (id)initWithBarButtonSystemItem:(UIBarButtonSystemItem)systemItem target:(id)target action:(SEL)action {
    NSLog(@"%s not supported!", __FUNCTION__);
    return nil;
}

- (id)initWithCustomView:(UIView *)customView {
    NSLog(@"%s not supported!", __FUNCTION__);
    return nil;
}

@end

你需要做的就是:

<强>1。实例化如下:

TapOrPressBarButtonItem* undoMenuButton = [[TapOrPressBarButtonItem alloc] initWithTitle:NSLocalizedString(@"Undo", @"Undo Menu Title") andDelegate:self];

---

<强>2。将按钮连接到导航栏:

[self.navigationItem setLeftBarButtonItem:undoMenuButton animated:NO];

---

<强>3。实现 TapOrPressButtonDelegate 协议(protocol)，您就完成了...

-(void)buttonTapped:(UIButton*)button withBarButtonItem:(UIBarButtonItem*)barButtonItem {
    [self menuItemUndo:barButtonItem];
}

-(void)buttonLongPressed:(UIButton*)button withBarButtonItem:(UIBarButtonItem*)barButtonItem {
    [self undoMenuClicked:barButtonItem];
}

希望这对其他人有帮助...