iOS学习——（转）UIResponder详解

本文转载自：ios开发 之 UIResponder详解　

　　我们知道UIResponder是所有视图View的基类，在iOS中UIResponder类是专门用来响应用户的操作处理各种事件的，包括触摸事件(Touch Events)、运动事件(Motion Events)、远程控制事件(Remote Control Events)。我们知道UIApplication、UIView、UIViewController这几个类是直接继承自UIResponder,所以这些类都可以响应事件。当然我们自定义的继承自UIView的View以及自定义的继承自UIViewController的控制器都可以响应事件。本文将详细介绍UIResponder类。

一 UIResponder.h文件注释版

　　首先，我们对UIResponder.h文件进行了研究和解释，并对各模块进行了注释添加，方便我们在阅读和学习时候的理解。在学习了UIView、NSObject的.h文件之后，我们发现这些基类的.h文件的组织架构基本类似，最初是定义该类中需要用到的一些枚举类型数据，然后对相应的协议进行定义，接着就是对本类进行定义，一些基本的属性和方法的定义，最后就是对本类做各种功能性的分类。

//
//  UIResponder.h

#import <Foundation/Foundation.h>
#import <UIKit/UIKitDefines.h>
#import <UIKit/UIEvent.h>

NS_ASSUME_NONNULL_BEGIN

@class UIPress;
@class UIPressesEvent;

#pragma mark - UIResponderStandardEditActions协议定义

@protocol UIResponderStandardEditActions <NSObject>
@optional
/** 剪切事件 */
- (void)cut:(nullable id)sender NS_AVAILABLE_IOS(3_0);
/** 复制事件 */
- (void)copy:(nullable id)sender NS_AVAILABLE_IOS(3_0);
/** 粘贴事件 */
- (void)paste:(nullable id)sender NS_AVAILABLE_IOS(3_0);
/** 选择事件 */
- (void)select:(nullable id)sender NS_AVAILABLE_IOS(3_0);
/** 全选事件 */
- (void)selectAll:(nullable id)sender NS_AVAILABLE_IOS(3_0);
/** 删除事件 */
- (void)delete:(nullable id)sender NS_AVAILABLE_IOS(3_2);
/** 从左到右写入字符串(居左) */
- (void)makeTextWritingDirectionLeftToRight:(nullable id)sender NS_AVAILABLE_IOS(5_0);
/** 从右到左写入字符串(居右) */
- (void)makeTextWritingDirectionRightToLeft:(nullable id)sender NS_AVAILABLE_IOS(5_0);
/** 切换字体为黑体(粗体) */
- (void)toggleBoldface:(nullable id)sender NS_AVAILABLE_IOS(6_0);
/** 切换字体为斜体 */
- (void)toggleItalics:(nullable id)sender NS_AVAILABLE_IOS(6_0);
/** 给文字添加下划线 */
- (void)toggleUnderline:(nullable id)sender NS_AVAILABLE_IOS(6_0);

/** 增加字体大小 */
- (void)increaseSize:(nullable id)sender NS_AVAILABLE_IOS(7_0);
/** 减小字体大小 */
- (void)decreaseSize:(nullable id)sender NS_AVAILABLE_IOS(7_0);

@end

#pragma mark - UIResponder类定义

NS_CLASS_AVAILABLE_IOS(2_0) @interface UIResponder : NSObject <UIResponderStandardEditActions>

#pragma mark - 响应者相关方法

/** 获取下一个响应者 */
#if UIKIT_DEFINE_AS_PROPERTIES
@property(nonatomic, readonly, nullable) UIResponder *nextResponder;
#else
- (nullable UIResponder *)nextResponder;
#endif

/** 是否允许成为第一响应者。默认返回NO */
#if UIKIT_DEFINE_AS_PROPERTIES
@property(nonatomic, readonly) BOOL canBecomeFirstResponder;
#else
- (BOOL)canBecomeFirstResponder;
#endif
/** 设置成为第一响应者 */
- (BOOL)becomeFirstResponder;

/** 是否允许放弃第一响应者。默认返回YES */
#if UIKIT_DEFINE_AS_PROPERTIES
@property(nonatomic, readonly) BOOL canResignFirstResponder;
#else
- (BOOL)canResignFirstResponder;
#endif
/** 设置放弃第一响应者 */
- (BOOL)resignFirstResponder;

/** 判断对象是否是第一响应者 */
#if UIKIT_DEFINE_AS_PROPERTIES
@property(nonatomic, readonly) BOOL isFirstResponder;
#else
- (BOOL)isFirstResponder;
#endif

#pragma mark - 触摸相关方法，一般用于响应屏幕触摸
/** 手指按下时响应 */
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
/** 手指移动时响应 */
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
/** 手指抬起时响应 */
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
/** 取消(意外中断, 如:电话, 系统警告窗等) */
- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
/** 3DTouch响应(iOS9.1后使用) */
- (void)touchesEstimatedPropertiesUpdated:(NSSet<UITouch *> *)touches NS_AVAILABLE_IOS(9_1);

#pragma mark - 深按相关方法，一般用于遥控器按键响应
/** 手指按压开始时响应 */
- (void)pressesBegan:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);
/** 手指按压位置移动时响应 */
- (void)pressesChanged:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);
/** 手指抬起接受按压时响应 */
- (void)pressesEnded:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);
/** 按压取消(意外中断, 如:电话, 系统警告窗等) */
- (void)pressesCancelled:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);

#pragma mark - 加速相关方法，一般用于摇一摇、运动事件监听等
/** 开始加速 */
- (void)motionBegan:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0);
/** 结束加速 */
- (void)motionEnded:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0);
/** 加速取消（意外中断, 如:电话, 系统警告窗等） */
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0);

/** 远程控制事件 */
- (void)remoteControlReceivedWithEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(4_0);

/** 返回UIMenuController需要显示的控件(如：复制，粘贴等) */
- (BOOL)canPerformAction:(SEL)action withSender:(nullable id)sender NS_AVAILABLE_IOS(3_0);

/** 返回响应的操作目标对象 */
- (nullable id)targetForAction:(SEL)action withSender:(nullable id)sender NS_AVAILABLE_IOS(7_0);

/** 获取响应链就近共享撤消管理 */
@property(nullable, nonatomic,readonly) NSUndoManager *undoManager NS_AVAILABLE_IOS(3_0);

@end

/** 快捷主键枚举 */
typedef NS_OPTIONS(NSInteger, UIKeyModifierFlags) {
    UIKeyModifierAlphaShift     = 1 << 16,  //!< Alpha+Shift键.
    UIKeyModifierShift          = 1 << 17,  //!< Shift键.
    UIKeyModifierControl        = 1 << 18,  //!< Control键.
    UIKeyModifierAlternate      = 1 << 19,  //!< Alt键.
    UIKeyModifierCommand        = 1 << 20,  //!< Command键.
    UIKeyModifierNumericPad     = 1 << 21,  //!< Num键.
} NS_ENUM_AVAILABLE_IOS(7_0);

#pragma mark - 快捷键对象

NS_CLASS_AVAILABLE_IOS(7_0) @interface UIKeyCommand : NSObject <NSCopying, NSSecureCoding>

/** 初始化对象 */
- (instancetype)init NS_DESIGNATED_INITIALIZER;
/** 初始化对象 */
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;

/** 获取快捷辅键（如快捷命令【Command+A】中的 A 键） */
@property (nonatomic,readonly) NSString *input;
/** 获取快捷主键（如快捷命令【Command+A】中的 Command 键） */
@property (nonatomic,readonly) UIKeyModifierFlags modifierFlags;
/** 显示给用户的快捷键标题 */
@property (nullable,nonatomic,copy) NSString *discoverabilityTitle NS_AVAILABLE_IOS(9_0);

/** 创建一个快捷键命令 */
+ (UIKeyCommand *)keyCommandWithInput:(NSString *)input modifierFlags:(UIKeyModifierFlags)modifierFlags action:(SEL)action;

/** 创建一个快捷键命令 */
+ (UIKeyCommand *)keyCommandWithInput:(NSString *)input modifierFlags:(UIKeyModifierFlags)modifierFlags action:(SEL)action discoverabilityTitle:(NSString *)discoverabilityTitle NS_AVAILABLE_IOS(9_0);

@end

#pragma mark - 响应快捷命令

@interface UIResponder (UIResponderKeyCommands)
/** 返回快捷键命令数组 */
@property (nullable,nonatomic,readonly) NSArray<UIKeyCommand *> *keyCommands NS_AVAILABLE_IOS(7_0);
@end

@class UIInputViewController;
@class UITextInputMode;
@class UITextInputAssistantItem;

#pragma mark - 输入视图

@interface UIResponder (UIResponderInputViewAdditions)

/** 键盘输入视图(系统默认的,可以自定义) */
@property (nullable, nonatomic, readonly, strong) __kindof UIView *inputView NS_AVAILABLE_IOS(3_2);
/** 弹出键盘时附带的视图 */
@property (nullable, nonatomic, readonly, strong) __kindof UIView *inputAccessoryView NS_AVAILABLE_IOS(3_2);

/** 输入助手配置键盘的快捷方式栏时使用 */
@property (nonnull, nonatomic, readonly, strong) UITextInputAssistantItem *inputAssistantItem NS_AVAILABLE_IOS(9_0) __TVOS_PROHIBITED __WATCHOS_PROHIBITED;

/** 键盘输入视图控制器 */
@property (nullable, nonatomic, readonly, strong) UIInputViewController *inputViewController NS_AVAILABLE_IOS(8_0);
/** 弹出键盘时附带的视图的视图控制器 */
@property (nullable, nonatomic, readonly, strong) UIInputViewController *inputAccessoryViewController NS_AVAILABLE_IOS(8_0);

/** 文本输入模式 */
@property (nullable, nonatomic, readonly, strong) UITextInputMode *textInputMode NS_AVAILABLE_IOS(7_0);

/** 文本输入模式标识 */
@property (nullable, nonatomic, readonly, strong) NSString *textInputContextIdentifier NS_AVAILABLE_IOS(7_0);
/** 根据设置的标识清除指定的文本输入模式 */
+ (void)clearTextInputContextIdentifier:(NSString *)identifier NS_AVAILABLE_IOS(7_0);

/** 重新刷新键盘输入视图 */
- (void)reloadInputViews NS_AVAILABLE_IOS(3_2);

@end

/** 特殊快捷辅键定义 */
UIKIT_EXTERN NSString *const UIKeyInputUpArrow         NS_AVAILABLE_IOS(7_0); //!< 上按键.
UIKIT_EXTERN NSString *const UIKeyInputDownArrow       NS_AVAILABLE_IOS(7_0); //!< 下按键.
UIKIT_EXTERN NSString *const UIKeyInputLeftArrow       NS_AVAILABLE_IOS(7_0); //!< 左按键.
UIKIT_EXTERN NSString *const UIKeyInputRightArrow      NS_AVAILABLE_IOS(7_0); //!< 右按键
UIKIT_EXTERN NSString *const UIKeyInputEscape          NS_AVAILABLE_IOS(7_0); //!< Esc按键.

#pragma mark - 响应者活动

@interface UIResponder (ActivityContinuation)
/** 用户活动 */
@property (nullable, nonatomic, strong) NSUserActivity *userActivity NS_AVAILABLE_IOS(8_0);
/** 更新用户活动 */
- (void)updateUserActivityState:(NSUserActivity *)activity NS_AVAILABLE_IOS(8_0);
/** 恢复用户活动 */
- (void)restoreUserActivityState:(NSUserActivity *)activity NS_AVAILABLE_IOS(8_0);
@end

NS_ASSUME_NONNULL_END

 二 UIResponder的使用

2.1 通过响应者链查找视图的视图控制器

 　　通过响应链查找视图控制器，nextResponder获取下一个响应者，响应者顺序为：

 

/**
 *  查找视图的视图控制器
 *
 *  @param view 视图
 *
 *  @return 返回视图的控制器
 */
- (UIViewController *)getControllerFromView:(UIView *)view {
    // 遍历响应者链。返回第一个找到视图控制器
    UIResponder *responder = view;
    while ((responder = [responder nextResponder])){
        if ([responder isKindOfClass: [UIViewController class]]){
            return (UIViewController *)responder;
        }
    }
    // 如果没有找到则返回nil
    return nil;
}

2.2 设置与取消第一响应者

　　UIView默认不允许设置为第一响应者，因此设置UIView为第一响应者需要重写canBecomeFirstResponder方法并返回YES。 设置为第一响应者后，对象则可以接受远程控制事件进行处理（如耳机线控）。UITextField、UITextView成为第一响应者后会弹出输入键盘，取消第一响应者则会隐藏输入键盘。 

//  ZMFirstResponderView.m

#import "ZMFirstResponderView.h"

@implementation ZMFirstResponderView

/** 演示设置为第一响应者 */
- (void)setBecomeFirstResponder {
    // 判断对象是否已经是第一响应者
    if ([self isFirstResponder]) {
        return;
    }
    // 判断对象是否允许成为第一响应者
    if ([self canBecomeFirstResponder]) {
        // 设置成为第一响应者
        [self becomeFirstResponder];
    }
}

/** 演示放弃第一响应者 */
- (void)setResignFirstResponder {
    // 判断对象是否不是第一响应者
    if (![self isFirstResponder]) {
        return;
    }
    // 判断对象是否允许放弃第一响应者
    if ([self canResignFirstResponder]) {
        // 设置放弃第一响应者
        [self resignFirstResponder];
    }
}

/** 重写方法，允许对象成为第一响应者 */
- (BOOL)canBecomeFirstResponder {
    return YES;
}

@end

2.3 触摸相关方法，一般用于响应屏幕触摸

/** 手指按下时响应 */
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event {
    [super touchesBegan:touches withEvent:event];
    NSLog(@"--->手指按下时响应");
}

/** 手指移动时响应 */
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event {
    [super touchesMoved:touches withEvent:event];
    NSLog(@"--->手指移动时响应");
}

/** 手指抬起时响应 */
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event {
    [super touchesEnded:touches withEvent:event];
    NSLog(@"--->手指抬起时响应");
}

/** 触摸取消(意外中断, 如:电话, Home键退出等) */
- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event {
    [super touchesCancelled:touches withEvent:event];
    NSLog(@"--->取消触摸响应");
}

2.4 加速相关方法，一般用于摇一摇、运动事件监听等

/** 开始加速 */
- (void)motionBegan:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0) {
    [super motionBegan:motion withEvent:event];
    NSLog(@"--->开始加速");
}

/** 结束加速 */
- (void)motionEnded:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0) {
    [super motionEnded:motion withEvent:event];
    NSLog(@"--->结束加速");
}

/** 加速取消（意外中断, 如:电话, Home键退出等） */
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0) {
    [super motionCancelled:motion withEvent:event];
    NSLog(@"--->加速取消");
}

2.5 远程控制方法，一般用于耳机线控

耳机线控要注意三点要素：

1. 启动接受远程事件：[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
2. 设置成为第一响应者（UIViewController，AppDelegate中不需要设置）
3. 获取音频的控制权

//  ZMAudioView.m

#import "ZMAudioView.h"
#import <AVFoundation/AVFoundation.h>

@implementation ZMAudioView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 1 启动接受远程事件
        [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
        //2  设置成为第一响应者
        [self becomeFirstResponder];
        // 3 播放一段静音文件，使APP获取音频的控制权
        NSURL *audioURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"mute_60s" ofType:@"mp3"]];
        AVAudioPlayer *audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:audioURL error:nil];
        [audioPlayer play];
    }
    return self;
}

/** 允许对象成为第一响应者 */
- (BOOL)canBecomeFirstResponder {
    return YES;
}

/** 远程控制事件响应 */
- (void)remoteControlReceivedWithEvent:(UIEvent *)receivedEvent {
    NSLog(@"--->耳机线控响应");
}

- (void)dealloc {
    // 停止接受远程事件
    [[UIApplication sharedApplication] endReceivingRemoteControlEvents];
    // 放弃第一响应者
    [self resignFirstResponder];
}

@end

2.6 在UILabel中实现长按菜单（复制、粘贴等）

为UILabel添加长按菜单需要注意几点：

1. 启用用户交互：self.userInteractionEnabled = YES;
2. 在显示菜单之前设置对象成为第一响应者（UIViewController，AppDelegate中不需要设置）
3. 返回菜单需要显示的按钮，并重写实现对应方法
4. 注册长按手势，显示菜单

//  ZMMenuLabel.m

#import "ZMMenuLabel.h"

@implementation ZMMenuLabel

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 启用用户交互
        self.userInteractionEnabled = YES;
        // 添加长按手势
        UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressMenu:)];
        longPressGesture.minimumPressDuration = 0.2;
        [self addGestureRecognizer:longPressGesture];
    }
    return self;
}

/** 允许对象成为第一响应者 */
- (BOOL)canBecomeFirstResponder {
    return YES;
}

/** 长按响应 */
- (void)longPressMenu:(UILongPressGestureRecognizer *)sender {
    if (sender.state == UIGestureRecognizerStateBegan) {
        // 设置成为第一响应者
        [self becomeFirstResponder];
        // 显示菜单
        UIMenuController *menuCtrl = [UIMenuController sharedMenuController];
        [menuCtrl setTargetRect:self.frame inView:self.superview];
        [menuCtrl setMenuVisible:YES animated:YES];
    }
}

/** 返回需要显示的菜单按钮 */
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
    // 只显示复制、粘贴按钮
    if (action == @selector(copy:) || action == @selector(paste:)) {
        return YES;
    }
    return NO;
}

/** 实现复制方法 */
- (void)copy:(id)sender {
    UIPasteboard *paste = [UIPasteboard generalPasteboard];
    paste.string = self.text;
}

/** 实现粘贴方法 */
- (void)paste:(id)sender {
    UIPasteboard *paste = [UIPasteboard generalPasteboard];
    self.text = paste.string;
}

@end

2.7 使用NSUndoManager实现画板撤销/重做功能

实现撤销/重做注意以下几点：

1. 在调用方法时需要添加注册一个对应的撤销方法
2. 撤销/ 重做只需要调用undoManager中的相应方法即可
3. 如果需要多个动作一起撤销则需要标记分组

/** ==============ZMDrawingBoardView.h文件=================== */

#import <UIKit/UIKit.h>

/** 画板View */
@interface ZMDrawingBoardView : UIView

@end


/** 划线Model */
@interface ZMLineModel : NSObject

@property (nonatomic) CGPoint begin;
@property (nonatomic) CGPoint end;

@end


/** ==============ZMDrawingBoardView.m文件=================== */

#import "ZMDrawingBoardView.h"

/** 画板View */
@interface ZMDrawingBoardView ()

@property (nonatomic, strong) ZMLineModel *currentLine;
@property (nonatomic, strong) NSMutableArray<ZMLineModel *> *toucheArray;

@end

@implementation ZMDrawingBoardView


- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self initSubView];
        self.backgroundColor = [UIColor whiteColor];
        self.toucheArray = [NSMutableArray array];
    }
    return self;
}

/** 绘制画板 */
- (void)drawRect:(CGRect)rect {
    // 获得上下文
    CGContextRef context = UIGraphicsGetCurrentContext();
    // 设置样式
    CGContextSetLineCap(context, kCGLineCapSquare);
    // 设置宽度
    CGContextSetLineWidth(context, 5.0);
    // 设置颜色
    CGContextSetStrokeColorWithColor(context, [[UIColor redColor] CGColor]);
    
    for (ZMLineModel *line in self.toucheArray) {
        // 开始绘制
        CGContextBeginPath(context);
        // 移动画笔到起点
        CGContextMoveToPoint(context, line.begin.x, line.begin.y);
        // 添加下一点
        CGContextAddLineToPoint(context, line.end.x, line.end.y);
        // 绘制完成
        CGContextStrokePath(context);
    }
}

/** 划线开始 */
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    // 标记开始撤销分组
    [self.undoManager beginUndoGrouping];
    
    for (UITouch *touch in touches) {
        // 记录起始点
        CGPoint locTouch = [touch locationInView:self];
        _currentLine = [[ZMLineModel alloc] init];
        _currentLine.begin = locTouch;
        _currentLine.end = locTouch;
    }
    
}

/** 划线移动 */
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches) {
        // 添加线条
        CGPoint locTouch = [touch locationInView:self];
        _currentLine.end = locTouch;
        [self addLine:_currentLine];
        // 当前线条
        _currentLine = [[ZMLineModel alloc] init];
        _currentLine.begin = locTouch;
        _currentLine.end = locTouch;
    }
}

/** 划线结束 */
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    // 结束标记撤销分组
    [self.undoManager endUndoGrouping];
}

/** 添加划线 */
- (void)addLine:(ZMLineModel *)line
{
    // 添加划线并重绘画板
    [self.toucheArray addObject:line];
    [self setNeedsDisplay];
    // 注册撤销方法
    [[self.undoManager prepareWithInvocationTarget:self] removeLine:line];
}

/** 移除划线 */
- (void)removeLine:(ZMLineModel *)line
{
    if ([self.toucheArray containsObject:line]) {
        // 移除划线并重绘画板
        [self.toucheArray removeObject:line];
        [self setNeedsDisplay];
        // 注册撤销方法
        [[self.undoManager prepareWithInvocationTarget:self] addLine:line];
    }
}

/** 撤销按钮点击响应 */
- (void)undoButtonAction:(id)sender {
    if ([self.undoManager canUndo]) {
        [self.undoManager undo];
    }
}

/** 重做按钮点击响应 */
- (void)redoButtonAction:(id)sender {
    if ([self.undoManager canRedo]) {
        [self.undoManager redo];
    }
}

/** 初始化子控件 */
- (void)initSubView {
    // 撤销按钮
    UIButton *undoButton = [UIButton buttonWithType:UIButtonTypeSystem];
    undoButton.frame = CGRectMake(0, 64, 70, 50);
    [undoButton setTitle:@"undo撤销" forState:UIControlStateNormal];
    [undoButton sizeToFit];
    [undoButton addTarget:self action:@selector(undoButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:undoButton];
    // 重做按钮
    UIButton *redoButton = [UIButton buttonWithType:UIButtonTypeSystem];
    redoButton.frame = CGRectMake(CGRectGetWidth(self.frame)-70, 64, 70, 50);
    [redoButton setTitle:@"redo重做" forState:UIControlStateNormal];
    [redoButton sizeToFit];
    [redoButton addTarget:self action:@selector(redoButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:redoButton];
}

@end

2.8 自定义快捷键

自定义快捷键需要注意两点：

1. 设置对象成为第一响应者（UIViewController，AppDelegate中不需要设置）
2. 重写keyCommands返回快捷命令组合

//  ZMKeyCommandView.m

#import "ZMKeyCommandView.h"

@implementation ZMKeyCommandView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 设置成为第一响应者
        [self becomeFirstResponder];
    }
    return self;
}

/** 允许对象成为第一响应者 */
- (BOOL)canBecomeFirstResponder {
    return YES;
}

/** 返回快捷命令数组 */
-(NSArray<UIKeyCommand *> *)keyCommands {
    return @[
             [UIKeyCommand keyCommandWithInput:UIKeyInputEscape modifierFlags:UIKeyModifierShift action:@selector(pressedShiftAndEscapeKey:) discoverabilityTitle:@"自定义[Shift+Esc]快捷键"],
             [UIKeyCommand keyCommandWithInput:@"a" modifierFlags:UIKeyModifierShift action:@selector(pressedShiftAndAKey:) discoverabilityTitle:@"自定义[Shift+A]快捷键"]
             ];
}

/** Shift+Esc快捷命令响应 */
-(void)pressedShiftAndEscapeKey:(UIKeyCommand *)keyCommand {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:keyCommand.discoverabilityTitle message:[NSString stringWithFormat:@"按下快捷辅键:[%@]", keyCommand.input] delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
    [alertView show];
}

/** Shift+A快捷命令响应 */
-(void)pressedShiftAndAKey:(UIKeyCommand *)keyCommand {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:keyCommand.discoverabilityTitle message:[NSString stringWithFormat:@"按下快捷辅键:[%@]", keyCommand.input] delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
    [alertView show];
}

@end

2.9 自定义UITextField输入键盘

//  ZMCustomInputView.m

#import "ZMCustomInputView.h"

#define MAIN_SCREEN_WIDTH [[UIScreen mainScreen] bounds].size.width   //!< 屏幕的Width

@interface ZMCustomInputView ()

@property (nonatomic, strong) UITextField *textField;
@property (nonatomic, strong) UIView *customInputView;
@property (nonatomic, strong) UIToolbar *customAccessoryView;

@end

@implementation ZMCustomInputView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 添加TextField
        [self addSubview:self.textField];
    }
    return self;
}

/** 懒加载textField */
- (UITextField *)textField {
    if (!_textField) {
        // 初始化textField
        _textField = [[UITextField alloc]initWithFrame:CGRectMake(50, 100, MAIN_SCREEN_WIDTH - 100, 30)];
        _textField.borderStyle = UITextBorderStyleRoundedRect;
        _textField.placeholder = @"测试";
        // 设置自定义键盘View
        _textField.inputView = self.customInputView;
        _textField.inputAccessoryView = self.customAccessoryView;
    }
    return _textField;
}

/** 懒加载customInputView */
- (UIView *)customInputView {
    if (!_customInputView) {
        _customInputView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, MAIN_SCREEN_WIDTH, 220)];
        _customInputView.backgroundColor = [UIColor lightGrayColor];
        UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(0, 100, MAIN_SCREEN_WIDTH, 40)];
        label.textAlignment = NSTextAlignmentCenter;
        label.text = @"自定义inputView";
        [_customInputView addSubview:label];
    }
    return _customInputView;
}

/** 懒加载customAccessoryView */
- (UIToolbar *)customAccessoryView {
    if (!_customAccessoryView) {
        _customAccessoryView = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, MAIN_SCREEN_WIDTH, 40)];
        _customAccessoryView.barTintColor = [UIColor orangeColor];
        UIBarButtonItem *space = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
        UIBarButtonItem *done = [[UIBarButtonItem alloc]initWithTitle:@"完成" style:UIBarButtonItemStyleDone target:self action:@selector(done)];
        [_customAccessoryView setItems:@[space, space, done]];
    }
    return _customAccessoryView;
}

/** 响应完成按钮 */
- (void)done {
    [self.textField resignFirstResponder];
}


@end