之前在 在iOS虚拟键盘上添加动态隐藏按钮一文中描叙了关于键盘上添加动态按钮的操作，发现键盘上的按钮显示出来的时候很僵硬，此处做了改进，添加了动画过渡，更换了图片，能够让人感觉按钮是随着键盘的动画显示而显示，随着键盘的动画退出而退出，看上去更加流畅些；

效果图:

- (void)viewDidLoad
{
    NSLog(@"%@",NSStringFromSelector(_cmd));
    [super viewDidLoad];
	exitButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [exitButton setImage:[UIImage imageNamed:@"down.png"] forState:UIControlStateNormal];
    CGRect exitBtFrame = CGRectMake(self.view.frame.size.width-48, self.view.frame.size.height , 48.0f, 30.0f);
    
    [exitButton setFrame:exitBtFrame];
      
   
    [self.view addSubview:exitButton];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardDidShow:) name:UIKeyboardWillShowNotification object:nil];  
    
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}

- (void)handleKeyboardDidShow:(NSNotification *)notification 
{
    NSLog(@"%@",NSStringFromSelector(_cmd));
    NSDictionary *info = [notification userInfo];
    NSLog(@"-->info:%@",info);
    CGRect keyboardFrame;
    [[info objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardFrame];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey]CGRectValue].size;
    NSValue *animationDurValue = [info objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
//    copy value
    [animationDurValue getValue:&animationDuration];
    
//    让键盘弹起的时候添加一个动画
    [UIView beginAnimations:@"animal" context:nil];
    [UIView setAnimationDuration:animationDuration];
    
    CGFloat distanceToMove = kbSize.height;
    NSLog(@"---->动态键盘高度:%f",distanceToMove);
    [self adjustPanelsWithKeyBordHeight:distanceToMove];
    [UIView commitAnimations];
    exitButton.hidden=NO;
    [exitButton addTarget:self action:@selector(CancelBackKeyboard:) forControlEvents:UIControlEventTouchDown];
    

}

- (void)handleKeyboardWillHide:(NSNotification *)notification 
{
    NSLog(@"%@",NSStringFromSelector(_cmd));

    NSDictionary *info = [notification userInfo];
    CGRect keyboardFrame;
    [[info objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardFrame];
    NSValue *animationDurValue = [info objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    //   把animationDurvalue 值拷贝到animationDuration中
    [animationDurValue getValue:&animationDuration];
    
    [UIView beginAnimations:@"animal" context:nil];
    [UIView setAnimationDuration:animationDuration];

    if (exitButton) {

        CGRect exitBtFrame = CGRectMake(self.view.frame.size.width - 48, self.view.frame.size.height, 48.0f, 30.0f);
        exitButton.frame = exitBtFrame;
        [self.view addSubview:exitButton];

    }
    [UIView commitAnimations];
    
}

-(void)adjustPanelsWithKeyBordHeight:(float) height
{
   
    NSLog(@"%@",NSStringFromSelector(_cmd));
    if (exitButton) {

       CGRect exitBtFrame = CGRectMake(self.view.frame.size.width - 48, self.view.frame.size.height - height-30, 48.0f, 30.0f);
        exitButton.frame = exitBtFrame;

        [self.view addSubview:exitButton];


    }
    
    
}

-(void)CancelBackKeyboard:(id)sender
{
    NSLog(@"%@",NSStringFromSelector(_cmd));
    
    [textField resignFirstResponder];
    
}

- (void)viewDidUnload
{
    [self setTextField:nil];
    exitButton=nil;
    [super viewDidUnload];
    
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

- (void)dealloc {
    [textField release];
    [exitButton release];
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [super dealloc];
}

     本文转自新风作浪 51CTO博客，原文链接：http://blog.51cto.com/duxinfeng/1160470，如需转载请自行联系原作者