iOS UI: UIMenuController | InputView 折腾记

本来 UIMenuController 这个东西挺简单的.
直到…
遇到 InputView, 我就醉了, 程序也崩溃了.

这里以 Demo 为主, 来说明问题.

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实现的效果很简单, 如下图

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ViewController.m

#import "ViewController.h"

@interface ViewController ()

// 罪魁祸首在这里
@property (nonatomic, strong) UIView *inputView;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self config];
}

// 这个方法必须重写, 否则不显示菜单
- (BOOL)canBecomeFirstResponder
{
    return YES;
}

- (void)config
{
    CGRect inputFrame = CGRectMake(100, 200, 200, 100);
    _inputView = [[UIView alloc] initWithFrame:inputFrame];
    [self.view addSubview:_inputView];

    CGRect bFrame = CGRectMake(100, 120, 120, 60);
    UIButton *btn = [[UIButton alloc] initWithFrame:bFrame];
    btn.backgroundColor = [UIColor greenColor];
    btn.titleLabel.font = [UIFont systemFontOfSize:14.f];
    btn.layer.borderWidth = 1.f;
    btn.layer.cornerRadius = 5.f;
    btn.layer.masksToBounds = YES;
    btn.layer.borderColor = [UIColor redColor].CGColor;
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [btn setTitle:@"点我弹出菜单" forState:UIControlStateNormal];

    btn.userInteractionEnabled = YES;
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                                          action:@selector(onTap:)];
    [btn addGestureRecognizer:tap];

    [self.view addSubview:btn];
}

- (void)onTap:(UITapGestureRecognizer *)recognizer
{
    // 写与不写, 暂时没有发现有什么卵用
    [self becomeFirstResponder];

    UIMenuController *menu = [UIMenuController sharedMenuController];
    UIMenuItem *delete = [[UIMenuItem alloc] initWithTitle:@"删除" action:@selector(deleteBtnClick)];
    NSArray *array = [NSArray arrayWithObjects:delete, nil];
    [menu setMenuItems:array];
    [menu setTargetRect:recognizer.view.frame inView:recognizer.view.superview];
    [menu setMenuVisible:YES animated:YES];
}

- (void)deleteBtnClick
{
    NSLog(@"tap the delete menu item");
}

@end

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在 iOS8 | iOS9 上面运行起来, 就 crash.
但是 iOS7 就安然无事.

crash 信息大概这个样子

Terminating app due to uncaught exception ‘UIViewControllerHierarchyInconsistency’,
reason: ‘child view controller: should have parent view controller: but requested parent is:’

最终找到问题在于, 声明并使用了一个全局 inputView.
注意, 不添加该 InputView, 也不会有问题, 即注释下面代码

[self.view addSubview:_inputView];

查阅文档知道, 从 iOS8 起, 需要检查 InputView 不应该有父视图.

可以看看, UIKit 里面的 inputView

解决方案

1.将原来的 inputView 改个名字.

2.不要使用全局变量 InputView.