IOS 数字键盘添加“完成”按钮

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController{

    UIButton *doneInKeyboardButton;
}

- (IBAction)NOBut:(id)sender;
- (IBAction)But:(id)sender;
@end

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    //注册通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
    

    
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (void)dealloc {
    //反注册通知
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    
    [super dealloc];
}

#pragma mark 键盘
- (void)handleKeyboardWillHide:(NSNotification *)notification
{
    if (doneInKeyboardButton.superview)
    {
        [doneInKeyboardButton removeFromSuperview];
    }
}

- (void)handleKeyboardDidShow:(NSNotification *)notification
{
    if (doneInKeyboardButton == nil)
    {
        doneInKeyboardButton = [[UIButton buttonWithType:UIButtonTypeCustom] retain];
        
        CGFloat screenHeight = [[UIScreen mainScreen] bounds].size.height;
        if(screenHeight==568.0f){//iphone5
            doneInKeyboardButton.frame = CGRectMake(0, 568 - 53, 106, 53);
        }else{//
            doneInKeyboardButton.frame = CGRectMake(0, 480 - 53, 106, 53);
        }
        
        doneInKeyboardButton.adjustsImageWhenHighlighted = NO;
        //图片
        [doneInKeyboardButton setImage:[UIImage imageNamed:@"btn_done_up@2x.png"] forState:UIControlStateNormal];
        [doneInKeyboardButton setImage:[UIImage imageNamed:@"btn_done_down@2x.png"] forState:UIControlStateHighlighted];
        [doneInKeyboardButton addTarget:self action:@selector(finishAction) forControlEvents:UIControlEventTouchUpInside];
    }
    
    
    UIWindow* tempWindow = [[[UIApplication sharedApplication] windows] objectAtIndex:1];
    
    if (doneInKeyboardButton.superview == nil)
    {
        [tempWindow addSubview:doneInKeyboardButton];    // 这里直接加到window上
    }
    
}

-(void)finishAction{
    [[[UIApplication sharedApplication] keyWindow] endEditing:YES];//关闭键盘
}


#pragma  mark  textview
- (IBAction)But:(id)sender {
    doneInKeyboardButton.hidden=YES;
}

- (IBAction)NOBut:(id)sender {
    doneInKeyboardButton.hidden=NO;
}
@end