在键盘上方添加按钮

1.inputAccessoryView

UITextField和UITextView的这个属性是readwrite的，可以自定义一个view设置为UITextField的inputAccessoryView

    UIView *toolView = [[UIView alloc] initWithFrame:CGRectMake(0,0, kScreenWidth,44)];
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(kScreenWidth - 60, 7,50, 30)];
    [button setTitle:@"完成"forState:UIControlStateNormal];
    [button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [toolView addSubview:button];
    
    UIButton *button1 = [[UIButton alloc] initWithFrame:CGRectMake(30, 7,50, 30)];
    [button1 setTitle:@"取消"forState:UIControlStateNormal];
    [button1 setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [toolView addSubview:button1];
    _textL.inputAccessoryView = toolView;

效果：

01.jpeg

当然可以直接将UIView替换成UIToolBar，自带背景色和border：

UIToolbar *bar = [[UIToolbar alloc] initWithFrame:CGRectMake(0,0, kScreenWidth,44)];

效果：

2.jpeg

不足之处：每次都要为UITextField或UITextView设置inputAccessoryView
改善：创建继承自UITextField或UITextView的类，在.m的init方法(或者drawRect:方法)统一设置：

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    UIToolbar *bar = [[UIToolbar alloc] initWithFrame:CGRectMake(0,0, kScreenWidth,44)];
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(kScreenWidth - 60, 7,50, 30)];
    [button setTitle:@"完成"forState:UIControlStateNormal];
    [button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [bar addSubview:button];

    UIButton *button1 = [[UIButton alloc] initWithFrame:CGRectMake(30, 7,50, 30)];
    [button1 setTitle:@"取消"forState:UIControlStateNormal];
    [button1 setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [bar addSubview:button1];
    self.inputAccessoryView = bar;
}

自定义TextField需要将按钮的事件传回到控制器执行(block/代理/通知 等方式)

2.监听键盘弹出和收回

添加通知：

[self.view addSubview:self.editView];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

收到通知之后可以获取键盘的一系列信息：

{
    UIKeyboardAnimationCurveUserInfoKey = 7;
    UIKeyboardAnimationDurationUserInfoKey = "0.25";
    UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {375, 258}}";
    UIKeyboardCenterBeginUserInfoKey = "NSPoint: {187.5, 775}";
    UIKeyboardCenterEndUserInfoKey = "NSPoint: {187.5, 538}";
    UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 667}, {375, 216}}";
    UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 409}, {375, 258}}";
    UIKeyboardIsLocalUserInfoKey = 1;
}

其中UIKeyboardFrameEndUserInfoKey是键盘弹出或收起结束之后的frame
处理：

- (void)keyboardWillShow:(NSNotification *)noti {
    NSDictionary *userInfo = noti.userInfo;
    CGRect endRect = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGFloat y = endRect.origin.y;
    [self.editView mas_remakeConstraints:^(MASConstraintMaker *make) {
         make.left.right.mas_equalTo(0);
         make.height.mas_equalTo(44);
         make.top.mas_equalTo(y - 44);
     }];
}

- (void)keyboardWillHide:(NSNotification *)noti {
    NSDictionary *userInfo = noti.userInfo;            
    CGRect endRect = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGFloat y = endRect.origin.y;
   [self.editView mas_remakeConstraints:^(MASConstraintMaker *make) {
         make.left.right.mas_equalTo(0);
         make.height.mas_equalTo(44);
         make.top.mas_equalTo(y - 44);
   }];
}

当然不要忘了移除通知