基本概念
UIKit框架中，可以直接执行拷贝黏贴操作的有 : UITextView、UITextField和UIWebView，其他控件需要实现相关方法
关于UIPasteboard
黏贴板是app内或者app之间，交换数据的标准机制
有公开的也有私有的，公开的黏贴板为系统级别(system pasteboard)，私有的黏贴板为应用程序级别(app pasteboard)，系统级别的黏贴板可以分享数据给任意其他app，应用程序级别的黏贴板只能分享给应用本身或者有相同team ID的应用
system pasteboard默认是持久化的，所谓持久化，就是设备重启或者app卸载依然有效，app pasteboard默认是非持久化的，可以通过persistent修改
@property(getter=isPersistent,nonatomic) BOOL persistent;
- 一般使用名为UIPasteboardNameGeneral的system pasteboard，这货是个单例对象，是整个手机所有app共享的黏贴板
UIPasteboard *generalPasteboard = [UIPasteboard generalPasteboard];
具体实现
以label为例，假设label轻触两下或者长按显示编辑菜单
屏幕快照 2016-04-28 下午8.55.08.png
过程将会涉及
UIPasteboard : 提供黏贴板分享数据，从黏贴板读-写数据
UIMenuController : 展示编辑菜单，用来执行拷贝-黏贴操作
UIResponder类的canPerformAction:withSender:方法，决定是否显示菜单某些命令，例如剪切
UIResponderStandardEditActions非正式协议中声明了copy、cut、paste等方法，需要实现
注 : 展示编辑菜单之前，系统会发送canPerformAction:withSender:消息给第一响应者，所以控件需要成为第一响应者来接收消息，并且在这个方法中，根据上下文的环境评估命令是否可用，例如当黏贴板没有可处理的数据时，响应者应该返回NO，阻止黏贴命令
0.首先打开用户交互，这个不要忘记，添加手势
- (void)awakeFromNib
{
[super awakeFromNib];
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(showMenu:)];
longPress.minimumPressDuration = 0.5;
[self addGestureRecognizer:longPress];
}
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
if (touch.tapCount == 2) {
[self showMenu:nil];
}
}
1.是否可以成为第一响应者，默认为NO
- (BOOL)canBecomeFirstResponder
{
return YES;
}
2.成为第一响应者
[self becomeFirstResponder];
3.创建编辑菜单
//获得单例对象
UIMenuController *menu = [UIMenuController sharedMenuController];
//view是参照物，指向以view为参照物的rect
[menu setTargetRect:self.bounds inView:self];
//显示
[menu setMenuVisible:YES animated:YES];
4.实现canPerformAction:withSender:方法，参数action具体会有哪些方法，基本都在UIResponderStandardEditActions声明了
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
NSLog(@"%@",NSStringFromSelector(action));
NSLog(@"%@",sender);
if (action == @selector(copy:) && self.text) {
//显示条件是文本不为空
return YES;
}
else if (action ==@selector(cut:) && self.text) {
//显示条件是文本不为空
return YES;
}
else if (action == @selector(paste:) && [UIPasteboard generalPasteboard].string) {
//显示条件是黏贴板不为空
return YES;
}
else {
return NO;
}
}
5.实现copy、cut、paste等方法
//实现剪切
- (void)cut:(id)sender
{
[self copy:sender];
self.text = nil;
}
//实现拷贝
- (void)copy:(id)sender
{
[UIPasteboard generalPasteboard].string = self.text;
}
//实现黏贴
- (void)paste:(id)sender
{
UIPasteboard *generalPasteboard = [UIPasteboard generalPasteboard];
NSMutableArray *types = [[NSMutableArray alloc] init];
[types addObjectsFromArray:UIPasteboardTypeListString];
if ([generalPasteboard containsPasteboardTypes:types]) {
self.text = generalPasteboard.string;
}
}
6.如果想要添加自定义命令，可以创建UIMenuItem
//添加自定义菜单项
UIMenuItem *item = [[UIMenuItem alloc] initWithTitle:@"Change Color" action:@selector(changeColor:)];
menu.menuItems = @[item];
再以imageView为例，展示图片拷贝黏贴操作
#import "CustomImageView.h"
@implementation CustomImageView
- (void)awakeFromNib
{
[super awakeFromNib];
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(showMenu:)];
longPress.minimumPressDuration = 0.5;
[self addGestureRecognizer:longPress];
}
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
if (touch.tapCount == 2) {
[self showMenu:nil];
}
}
/**
* 4.响应者是否可以执行该方法
*
* @param action 方法
* @param sender 请求对象
*/
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
if (action == @selector(copy:) && self.image) {
return YES;
}
else if (action == @selector(cut:) && self.image) {
return YES;
}
else if (action == @selector(paste:) && [UIPasteboard generalPasteboard].image) {
return YES;
}
else if (action == @selector(changeColor:)) {
return YES;
}
else {
return NO;
}
}
/**
* 1.是否可以成为第一响应者，默认为NO
*/
- (BOOL)canBecomeFirstResponder
{
return YES;
}
- (void)showMenu:(UILongPressGestureRecognizer *)longPress
{
if (longPress.state == UIGestureRecognizerStateEnded || longPress == nil) {
//2.成为第一响应者
[self becomeFirstResponder];
//添加自定义菜单项
UIMenuItem *item = [[UIMenuItem alloc] initWithTitle:@"Change Color" action:@selector(changeColor:)];
//3.创建编辑菜单
UIMenuController *menu = [UIMenuController sharedMenuController];
[menu setTargetRect:self.bounds inView:self];
menu.menuItems = @[item];
[menu setMenuVisible:YES animated:YES];
}
}
- (void)cut:(id)sender
{
[self copy:sender];
self.image = nil;
}
- (void)copy:(id)sender
{
[UIPasteboard generalPasteboard].image = self.image;
}
- (void)paste:(id)sender
{
UIPasteboard *generalPasteboard = [UIPasteboard generalPasteboard];
NSMutableArray *types = [[NSMutableArray alloc] init];
[types addObjectsFromArray:UIPasteboardTypeListImage];
if ([generalPasteboard containsPasteboardTypes:types]) {
self.image = generalPasteboard.image;
}
}
- (void)changeColor:(id)sender
{
self.backgroundColor = [UIColor colorWithRed:arc4random_uniform(256)/255.0 green:arc4random_uniform(256)/255.0 blue:arc4random_uniform(256)/255.0 alpha:1.0];
}
屏幕快照 2016-04-28 下午9.28.28.png
屏幕快照 2016-04-28 下午9.30.34.png
References :
Displaying and Managing the Edit Menu
Copy, Cut, and Paste Operations
