iOS剪切板相关

在使用淘宝的时候, 有一个功能就是复制吱口令到淘宝会自动判断剪切板里面的内容, 于是自己整理了一下关于剪切板的知识.

1. 构造方法

UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
pasteboard.string = @"http:www.google.com";

//获取系统级别的剪切板
+(UIPasteboard *)generalPasteboard;

//获取一个自定义的剪切板 name参数为此剪切板的名称 create参数用于设置当这个剪切板不存在时 是否进行创建
+(nullable UIPasteboard )pasteboardWithName:(NSString )pasteboardName create:(BOOL)create;

//获取一个应用内可用的剪切板
+(UIPasteboard *)pasteboardWithUniqueName;

2. 可以存放的类型

剪切板里面可以放: string、strings、URL、URLs、image、images、color、colors

3. iOS原生控件支持剪切板的只有UITextField 、UITextView、UIWebView

如果一个控件能够使用UIPasteBoard需要重写
-(BOOL)canBecomeFirstResponder
-(BOOL)canPerformAction:(SEL)action withSender:(id)sender
这两个方法，前者设置控件能接收到事件(能成为第一响应者)，后者决定这个控件能够使用复制、剪切、选中、全选、粘贴等的哪一种或几种功能,并重载对应的
-(void)copy:(id)sender //复制
-(void)cut:(id)sender //剪切
-(void)select:(id)sender //选择
-(void)selectAll:(id)sender //全选
-(void)paste:(id)sender //粘贴
等方法
使用UIMenuController来显示菜单

//能成为第一响应者
-(BOOL)canBecomeFirstResponder{
  return YES;
}

//实现复制、剪切、选择、全选、粘贴等方法
-(BOOL)canPerformAction:(SEL)action withSender:(id)sender{
  NSArray* array = @[@”copy:”,@”cut:”,@”select:”,@”selectAll:”,@”paste:”];
  if ([array containsObject:NSStringFromSelector(action)]) {
    return YES;
  }
  return [super canPerformAction:action withSender:sender];
}

//实现方法
//复制
-(void)copy:(id)sender {
  UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
  pasteboard.string = @”www.google.com";
}
//剪切
-(void)cut:(id)sender {
  UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
  pasteboard.string = @”www.google.com";
}
//选择
-(void)select:(id)sender {
  //逻辑
}
//全选
-(void)selectAll:(id)sender {
  //逻辑
}
//粘贴
-(void)paste:(id)sender {
  UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
  self.textField.text = pasteboard.string;
}

4. 显示快捷菜单UIMenuController

UIMenuController：显示一个快捷菜单，用来展示复制、剪贴、粘贴等选择的项。对于自定义控件需要实现上面两个方法

UIMenuController *menu = [UIMenuController sharedMenuController];获取menu

@property(nonatomic) UIMenuControllerArrowDirection arrowDirection 显示的方向

-(void)setTargetRect:(CGRect)targetRect inView:(UIView *)targetView;设置显示范围和视图
@property(nonatomic,getter=isMenuVisible) BOOL menuVisible; // default is NO
-(void)setMenuVisible:(BOOL)menuVisible animated:(BOOL)animated;必须手动设置为true才会显示

5. 对于剪切板的监听

UIPasteboard系统自带了4个通知:
UIPasteboardChangedNotification //剪切板更改
UIPasteboardChangedTypesAddedKey //剪切板类型增加
UIPasteboardChangedTypesRemovedKey //剪切板类型移除
UIPasteboardRemovedNotification //剪切板移除

//进入前台通知
UIApplicationDidBecomeActiveNotification

回到开头的问题, 我们可以在需要的页面监听UIApplicationDidBecomeActiveNotification程序已经是活动的通知, 在通知里面获取剪切板里面的内容, 根据内容判断是否需要处理.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(show:) name:UIApplicationDidBecomeActiveNotification object:nil];
-(void)show:(id)sender {
  NSString *string = [UIPasteboard generalPasteboard].string;
  //代码逻辑
}