有一个320*480的UITextView，点击UITextView的时候，下面的部分会被弹出的软键盘挡住，我们可以将UITextView的高度改为480 － 软键盘的高度，关闭软键盘后，高度恢复为原始高度。
 
- (void)viewDidLoad
{
    [super viewDidLoad];
    self.textView = [[UITextView alloc] initWithFrame:self.view.frame];
    self.textView.textColor = [UIColor blackColor];
    self.textView.font = [UIFont fontWithName:@"Arial" size:18];
    self.textView.backgroundColor = [UIColor whiteColor];
    self.textView.text = @"This is the text view example, we can edit, delete, add content in the text view.";
    self.textView.returnKeyType = UIReturnKeyDefault;
    self.textView.keyboardType = UIKeyboardTypeDefault;
    self.textView.scrollEnabled = YES;
    self.textView.autoresizingMask = UIViewAutoresizingFlexibleHeight;
    [self.view addSubview: self.textView];
    [self.textView release];
}
 
- (void)viewDidUnload
{
    [super viewDidUnload];
    self.textView = nil;
}
 
- (void)dealloc {
    [textView release], textView = nil;
    [super dealloc];
}
 
- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}
 
- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
 
- (void)keyboardWillShow:(NSNotification *)aNotification
{
    CGRect keyboardRect = [[[aNotification userInfo] objectForKey:UIKeyboardBoundsUserInfoKey] CGRectValue];
    NSTimeInterval animationDuration = [[[aNotification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    CGRect frame = self.view.frame;
    frame.size.height -= keyboardRect.size.height;
    [UIView beginAnimations:@"ResizeForKeyboard" context:nil];
    [UIView setAnimationDuration:animationDuration];
    self.view.frame = frame;
    [UIView commitAnimations];
}
 
- (void)keyboardWillHide:(NSNotification *)aNotification
{
    CGRect keyboardRect = [[[aNotification userInfo] objectForKey:UIKeyboardBoundsUserInfoKey] CGRectValue];
    NSTimeInterval animationDuration = [[[aNotification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    CGRect frame = self.view.frame;
    frame.size.height += keyboardRect.size.height;
    [UIView beginAnimations:@"ResizeForKeyboard" context:nil];
    [UIView setAnimationDuration:animationDuration];
    self.view.frame = frame;
    [UIView commitAnimations];
}