解决虚拟键盘挡住UITextField

方法一：

http://blog.csdn.net/xiaotanyu13/article/details/7711954

因为屏幕太小的缘故，一个键盘跳出来总是把输入框挡住，所以需要移动屏幕来匹配键盘

#pragma mark -

#pragma mark 解决虚拟键盘挡住UITextField的方法

- (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);

//CGRect rect = CGRectMake(0.0f, 20.0f, 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];

}

#pragma mark -

只要在代码中加入这三个文件，然后将自身delegate



如右上角 就可以实现屏幕的移动了，
但是这里经常会有屏幕移动后不能返回的问题，这里的解决方案就是

- (IBAction)backgroundTap:(id)sender {

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;

｝

在backgroundTap函数中添加这些代码，这样屏幕就会返回正常了。
效果：



方法二：
http://stackoverflow.com/questions/1126726/how-to-make-a-uitextfield-move-up-when-keyboard-is-present

#define kOFFSET_FOR_KEYBOARD 80.0

-(void)keyboardWillShow {
// Animate the current view out of the way
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
else if (self.view.frame.origin.y < 0)
{
[self setViewMovedUp:NO];
}
}

-(void)keyboardWillHide {
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
else if (self.view.frame.origin.y < 0)
{
[self setViewMovedUp:NO];
}
}

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
if ([sender isEqual:mailTf])
{
//move the main view, so that the keyboard does not hide it.
if  (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
}
}

//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.3]; // if you want to slide up the view

CGRect rect = self.view.frame;
if (movedUp)
{
// 1. move the view's origin up so that the text field that will be hidden come above the keyboard
// 2. increase the size of the view so that the area behind the keyboard is covered up.
rect.origin.y -= kOFFSET_FOR_KEYBOARD;
rect.size.height += kOFFSET_FOR_KEYBOARD;
}
else
{
// revert back to the normal state.
rect.origin.y += kOFFSET_FOR_KEYBOARD;
rect.size.height -= kOFFSET_FOR_KEYBOARD;
}
self.view.frame = rect;

[UIView commitAnimations];
}

- (void)viewWillAppear:(BOOL)animated
{
// register for keyboard notifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow)
name:UIKeyboardWillShowNotification
object:nil];

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

- (void)viewWillDisappear:(BOOL)animated
{
// unregister for keyboard notifications while not visible.
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillShowNotification
object:nil];

[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillHideNotification
object:nil];
}

效果：



问题：Apple recommends against using a constant for the size of the keyboard?