关于输入框的UIMenuController

屏幕快照 2017-05-19 下午5.05.29.png

####背景
项目中有个页面有一个自定义的textView输入框，其一用于四六级写作翻译的答题，其二用于发表评论； 产品需求是答题时不能粘贴(专治懒癌学生), 其二对输入不做限制；百度搜索，发现问题的关键在于textView的- (BOOL)canPerformAction:(SEL)action withSender:(id)sender方法，下面容我慢慢道来

脑子简单，没多想的后果

1、自定义了一个ForbidPasteTextView，添加是否禁止粘贴属性@property(nontamic,assign)BOOL forbidPaste，重写- (BOOL)canPerformAction:(SEL)action withSender:(id)sender

-(BOOL)canPerformAction:(SEL)action withSender:(id)sender{
    
    if (self.forbidPaste && action==@selector(paste:)) {
        return NO;
    }
    return YES;
}

结果 ：
长按输入框，粘贴的确没有出现，可是我看到了剪切、拷贝、全选、删除。。。。。。
更严重的是，我点击删除，程序崩溃了。。。

屏幕快照 2017-05-19 下午4.50.20.png

-[ForbidPasteTextView delete:]: unrecognized selector sent to instance 0x7ff2a1001200 ， 这样一看我就明白了，真没我想的那么简单，既然重写- (BOOL)canPerformAction:(SEL)action withSender:(id)sender，那就是要付出代价的，写就要写完整咯，既然重写了菜单响应的方法，那菜单的点击方法也要写

修正，既然要重写菜单的方法，那么多，够用就行了，所以，除了粘贴，就留了剪切和拷贝

@implementation ForbidPoateTextView

//只禁止粘贴
-(BOOL)canPerformAction:(SEL)action withSender:(id)sender{
    if (self.forbidPaste && (action ==  @selector(paste:))) {
        return NO;
    }
    if (action == @selector(copy:) || action == @selector(paste:) || action == @selector(cut:)) {
        return YES;
    }else{
        return NO;
    }
    return YES;
}
- (void)copy:(UIMenuController *)menu
{
    UIPasteboard *board = [UIPasteboard generalPasteboard];
    board.string = self.text;
    
}
- (void)paste:(UIMenuController *)menu
{
    UIPasteboard *board = [UIPasteboard generalPasteboard];
    self.text = board.string;
}
- (void)cut:(UIMenuController *)menu
{
    [self copy:menu];
    self.text = nil;
}
- (BOOL)canBecomeFirstResponder
{
    return YES;
}

屏幕快照 2017-05-19 下午5.05.29.png

放大招， 完全自定义自己的MenuController

//返回YES，会调起菜单  内部可以自定义菜单UIMenuItem
-(BOOL)canPerformAction:(SEL)action withSender:(id)sender{
    
    UIMenuController *menuControl = [UIMenuController sharedMenuController];
    UIMenuItem *item = [[UIMenuItem alloc]initWithTitle:@"插入表情" action:@selector(insertFace:)];
    menuControl.menuItems = @[item];
   //保留系统的拷贝和粘贴菜单
    if (action==@selector(insertFace:) || action == @selector(copy:) || action == @selector(paste:)) {
        return YES;
    }
    return NO;
}
- (void)insertFace:(UIMenuController *)menu
{
    NSLog(@"插入表情");
}
- (void)copy:(UIMenuController *)menu
{
    UIPasteboard *board = [UIPasteboard generalPasteboard];
    board.string = self.text;
    
}

- (void)paste:(UIMenuController *)menu
{
    UIPasteboard *board = [UIPasteboard generalPasteboard];
    self.text = board.string;
}

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

@end

屏幕快照 2017-05-19 下午5.15.31.png

谢谢！