UITextField控件处理键盘弹出时遮住输入框的问题。

原文连接：
http://www.devdiv.com/thread-70159-1-1.html

实现以下三个方法，如果弹出的键盘会遮住输入框 ，整体的界面会向上移动，这样就不会遮住输入框了。自己增加UITextFieldDelegate委托。
只适合iPhone,如果想要支持iPad,只要把216改成iPad上面键盘的高度即可。

- (void)keyboardWillShow:(NSNotification *)noti
{        
        //键盘输入的界面调整        
        //键盘的高度
        float height = 216.0;                
        CGRect frame = self.view.frame;        
        frame.size = CGSizeMake(frame.size.width, frame.size.height - height);        
        [UIView beginAnimations:@"Curl"context:nil];//动画开始          
        [UIView setAnimationDuration:0.30];           
        [UIView setAnimationDelegate:self];          
        [self.view setFrame:frame];         
        [UIView commitAnimations];         
}


- (BOOL)textFieldShouldReturn:(UITextField *)textField 
{        
    // When the user presses return, take focus away from the text field so that the keyboard is dismissed.        
    NSTimeInterval animationDuration = 0.30f;        
    [UIView beginAnimations:@"ResizeForKeyboard" context:nil];        
    [UIView setAnimationDuration:animationDuration];        
    CGRect rect = CGRectMake(0.0f, 0.0f, self.view.frame.size.width, self.view.frame.size.height);        
    self.view.frame = rect;        
    [UIView commitAnimations];        
    [textField resignFirstResponder];
    return YES;        
}

- (void)textFieldDidBeginEditing:(UITextField *)textField
{        
        CGRect frame = textField.frame;
        int offset = frame.origin.y + 32 - (self.view.frame.size.height - 216.0);//键盘高度216
        NSTimeInterval animationDuration = 0.30f;                
        [UIView beginAnimations:@"ResizeForKeyBoard" context:nil];                
        [UIView setAnimationDuration:animationDuration];
        float width = self.view.frame.size.width;                
        float height = self.view.frame.size.height;        
        if(offset > 0)
        {
                CGRect rect = CGRectMake(0.0f, -offset,width,height);                
                self.view.frame = rect;        
        }        
        [UIView commitAnimations];                
}

另外我自己做了一点修改：
在实际用的时候，键盘消失原来的控件并没有回归都原来的位置，而是上移了20个像素，我估计是因为顶部Bar的原因，只要将22行代码改成如下就可以了：
CGRect rect = CGRectMake(0.0f, 20.0f, self.view.frame.size.width, self.view.frame.size.height);